From dfd19f5256d218a732afa71c5cc306c106da3b07 Mon Sep 17 00:00:00 2001
From: Martin Yeo <martin.yeo@metoffice.gov.uk>
Date: Thu, 10 Feb 2022 14:06:54 +0000
Subject: [PATCH 01/50] Benchmarks Nox session improvements.

---
 noxfile.py | 126 ++++++++++++++++++++++++++++++++++++++++++++---------
 1 file changed, 105 insertions(+), 21 deletions(-)

diff --git a/noxfile.py b/noxfile.py
index 8b23948677..8dd9152f8f 100755
--- a/noxfile.py
+++ b/noxfile.py
@@ -8,6 +8,8 @@
 import hashlib
 import os
 from pathlib import Path
+from tempfile import NamedTemporaryFile
+from typing import Literal
 
 import nox
 from nox.logger import logger
@@ -291,21 +293,46 @@ def linkcheck(session: nox.sessions.Session):
 
 @nox.session(python=PY_VER[-1], venv_backend="conda")
 @nox.parametrize(
-    ["ci_mode"],
-    [True, False],
-    ids=["ci compare", "full"],
+    "run_type",
+    ["overnight", "branch", "custom"],
+    ids=["overnight", "branch", "custom"],
 )
-def benchmarks(session: nox.sessions.Session, ci_mode: bool):
+def benchmarks(session: nox.sessions.Session, run_type: Literal["overnight", "branch", "custom"]):
     """
     Perform esmf-regrid performance benchmarks (using Airspeed Velocity).
 
+    All run types require a single Nox positional argument (e.g.
+    ``nox --session="foo" .. my_pos_arg``) - detailed in the parameters
+    section - and can optionally accept a series of further arguments that will
+    be added to session's ASV command.
+
     Parameters
     ----------
     session: object
         A `nox.sessions.Session` object.
-    ci_mode: bool
-        Run a cut-down selection of benchmarks, comparing the current commit to
-        the last commit for performance regressions.
+    run_type: {"overnight", "branch", "custom"}
+        * ``overnight``: benchmarks all commits between the input **first
+          commit** to ``HEAD``, comparing each to its parent for performance
+          shifts. If a commit causes shifts, the output is saved to a file:
+          ``performance-shifts/<commit-sha>``. Designed for checking the
+          previous 24 hours' commits, typically in a scheduled script.
+        * ``branch``: Performs the same operations as ``overnight``, but always
+          on two commits only - ``HEAD``, and ``HEAD``'s merge-base with the
+          input **base branch**. Output from this run is never saved to a file.
+          Designed for testing if the active branch's changes cause performance
+          shifts - anticipating what would be caught by ``overnight`` once
+          merged.
+        * ``custom``: run ASV with the input **ASV command type**, without any
+          preset arguments - must all be supplied by the user. So just like
+          running ASV manually, with the convenience of re-using the session's
+          scripted setup steps.
+
+    Examples
+    --------
+    * ``nox --session="benchmarks(overnight)" .. a1b23d4``
+    * ``nox --session="benchmarks(branch)" .. upstream/main``
+    * ``nox --session="benchmarks(branch)" .. upstream/main --bench=regridding``
+    * ``nox --session="benchmarks(custom)" .. continuous a1b23d4 HEAD --quick``
 
     Notes
     -----
@@ -319,18 +346,75 @@ def benchmarks(session: nox.sessions.Session, ci_mode: bool):
     # Skip over setup questions for a new machine.
     session.run("asv", "machine", "--yes")
 
-    def asv_exec(*sub_args: str) -> None:
-        run_args = ["asv", *sub_args]
-        session.run(*run_args)
-
-    if ci_mode:
-        # If on a PR: compare to the base (target) branch.
-        #  Else: compare to previous commit.
-        previous_commit = os.environ.get("PR_BASE_SHA", "HEAD^1")
-        try:
-            asv_exec("continuous", "--factor=1.2", previous_commit, "HEAD")
-        finally:
-            asv_exec("compare", previous_commit, "HEAD")
+    # All run types require one Nox posarg.
+    run_type_arg = {
+        "overnight": "first commit",
+        "branch": "base branch",
+        "custom": "ASV command type"
+    }
+    if run_type not in run_type_arg.keys():
+        message = f"Unsupported run-type: {run_type}"
+        raise NotImplementedError(message)
+    first_arg = session.posargs[0]
+    if not first_arg:
+        message = (
+            f"Missing mandatory first Nox session posarg: {run_type_arg[run_type]}"
+        )
+        raise ValueError(message)
+    # Optional extra arguments to be passed down to ASV.
+    asv_args = session.posargs[1:]
+
+    def asv_compare(*commits):
+        """Run through a list of commits comparing each one to the next."""
+        commits = [commit[:8] for commit in commits]
+        shifts_dir = Path("performance-shifts")
+        for i in range(len(commits) - 1):
+            before = commits[i]
+            after = commits[i + 1]
+            asv_command_ = f"asv compare {before} {after} --factor=1.2 --split"
+            session.run(*asv_command_.split(" "))
+
+            if run_type == "overnight":
+                # Record performance shifts.
+                # Run the command again but limited to only showing performance
+                #  shifts.
+                shifts = session.run(*asv_command_.split(" "), "--only-changed", silent=True)
+                if shifts:
+                    # Write the shifts report to a file.
+                    shifts_dir.mkdir(exist_ok=True)
+                    shifts_path = shifts_dir / after
+                    with shifts_path.open("w") as shifts_file:
+                        shifts_file.write(shifts)
+
+    # Common ASV arguments used for both `overnight` and `bench` run_types.
+    asv_harness = "asv run {posargs} --attribute rounds=4 --interleave-rounds --strict"
+
+    if run_type == "overnight":
+        first_commit = first_arg
+        commit_range = f"{first_commit}^^.."
+        asv_command = asv_harness.format(posargs=commit_range)
+        session.run(*asv_command.split(" "), *asv_args)
+
+        # git rev-list --first-parent is the command ASV uses.
+        git_command = f"git rev-list --first-parent {commit_range}"
+        commit_string = session.run(*git_command.split(" "), silent=True, external=True)
+        commit_list = commit_string.rstrip().split("\n")
+        asv_compare(*reversed(commit_list))
+
+    elif run_type == "branch":
+        base_branch = first_arg
+        git_command = f"git merge-base HEAD {base_branch}"
+        merge_base = session.run(*git_command.split(" "), silent=True, external=True)[:8]
+
+        with NamedTemporaryFile("w") as hashfile:
+            hashfile.writelines([merge_base, "\n", "HEAD"])
+            hashfile.flush()
+            commit_range = f"HASHFILE:{hashfile.name}"
+            asv_command = asv_harness.format(posargs=commit_range)
+            session.run(*asv_command.split(" "), *asv_args)
+
+        asv_compare(merge_base, "HEAD")
+
     else:
-        # f5ceb808 = first commit supporting nox --install-only .
-        asv_exec("run", "f5ceb808..HEAD")
+        asv_command_type = first_arg
+        session.run("asv", asv_command_type, *asv_args)

From 0b640fbd40ab64ed399ac8790b8602ff6d12e862 Mon Sep 17 00:00:00 2001
From: Martin Yeo <martin.yeo@metoffice.gov.uk>
Date: Thu, 10 Feb 2022 14:08:18 +0000
Subject: [PATCH 02/50] Benchmarks Nox session improvements.

---
 noxfile.py | 26 +++++++++++++++++++-------
 1 file changed, 19 insertions(+), 7 deletions(-)

diff --git a/noxfile.py b/noxfile.py
index 8dd9152f8f..1b32ecba70 100755
--- a/noxfile.py
+++ b/noxfile.py
@@ -297,7 +297,10 @@ def linkcheck(session: nox.sessions.Session):
     ["overnight", "branch", "custom"],
     ids=["overnight", "branch", "custom"],
 )
-def benchmarks(session: nox.sessions.Session, run_type: Literal["overnight", "branch", "custom"]):
+def benchmarks(
+    session: nox.sessions.Session,
+    run_type: Literal["overnight", "branch", "custom"],
+):
     """
     Perform esmf-regrid performance benchmarks (using Airspeed Velocity).
 
@@ -350,7 +353,7 @@ def benchmarks(session: nox.sessions.Session, run_type: Literal["overnight", "br
     run_type_arg = {
         "overnight": "first commit",
         "branch": "base branch",
-        "custom": "ASV command type"
+        "custom": "ASV command type",
     }
     if run_type not in run_type_arg.keys():
         message = f"Unsupported run-type: {run_type}"
@@ -358,7 +361,8 @@ def benchmarks(session: nox.sessions.Session, run_type: Literal["overnight", "br
     first_arg = session.posargs[0]
     if not first_arg:
         message = (
-            f"Missing mandatory first Nox session posarg: {run_type_arg[run_type]}"
+            f"Missing mandatory first Nox session posarg: "
+            f"{run_type_arg[run_type]}"
         )
         raise ValueError(message)
     # Optional extra arguments to be passed down to ASV.
@@ -378,7 +382,9 @@ def asv_compare(*commits):
                 # Record performance shifts.
                 # Run the command again but limited to only showing performance
                 #  shifts.
-                shifts = session.run(*asv_command_.split(" "), "--only-changed", silent=True)
+                shifts = session.run(
+                    *asv_command_.split(" "), "--only-changed", silent=True
+                )
                 if shifts:
                     # Write the shifts report to a file.
                     shifts_dir.mkdir(exist_ok=True)
@@ -387,7 +393,9 @@ def asv_compare(*commits):
                         shifts_file.write(shifts)
 
     # Common ASV arguments used for both `overnight` and `bench` run_types.
-    asv_harness = "asv run {posargs} --attribute rounds=4 --interleave-rounds --strict"
+    asv_harness = (
+        "asv run {posargs} --attribute rounds=4 --interleave-rounds --strict"
+    )
 
     if run_type == "overnight":
         first_commit = first_arg
@@ -397,14 +405,18 @@ def asv_compare(*commits):
 
         # git rev-list --first-parent is the command ASV uses.
         git_command = f"git rev-list --first-parent {commit_range}"
-        commit_string = session.run(*git_command.split(" "), silent=True, external=True)
+        commit_string = session.run(
+            *git_command.split(" "), silent=True, external=True
+        )
         commit_list = commit_string.rstrip().split("\n")
         asv_compare(*reversed(commit_list))
 
     elif run_type == "branch":
         base_branch = first_arg
         git_command = f"git merge-base HEAD {base_branch}"
-        merge_base = session.run(*git_command.split(" "), silent=True, external=True)[:8]
+        merge_base = session.run(
+            *git_command.split(" "), silent=True, external=True
+        )[:8]
 
         with NamedTemporaryFile("w") as hashfile:
             hashfile.writelines([merge_base, "\n", "HEAD"])

From 43fa7261df2c04026e9ca0eeefa2e1ba3b929ad0 Mon Sep 17 00:00:00 2001
From: Martin Yeo <martin.yeo@metoffice.gov.uk>
Date: Thu, 10 Feb 2022 23:39:20 +0000
Subject: [PATCH 03/50] GHA overnight benchmark action.

---
 .github/workflows/benchmark.yml | 51 ++++++++++++++++++++++++---------
 noxfile.py                      | 10 +++++--
 2 files changed, 44 insertions(+), 17 deletions(-)

diff --git a/.github/workflows/benchmark.yml b/.github/workflows/benchmark.yml
index b489eba036..a12068d514 100644
--- a/.github/workflows/benchmark.yml
+++ b/.github/workflows/benchmark.yml
@@ -3,8 +3,9 @@
 name: benchmark-check
 
 on:
-  # Triggers the workflow on push or pull request events but only for the master branch
-  pull_request:
+  # Runs every day at 23:00.
+  schedule:
+    - cron: 0 23 * * *
 
 jobs:
   benchmark:
@@ -22,12 +23,6 @@ jobs:
       # Checks-out your repository under $GITHUB_WORKSPACE, so your job can access it
       - uses: actions/checkout@v2
 
-      - name: Fetch the PR base branch too
-        run: |
-          git fetch --depth=1 origin ${{ github.event.pull_request.base.ref }}
-          git branch _base FETCH_HEAD
-          echo PR_BASE_SHA=$(git rev-parse _base) >> $GITHUB_ENV
-
       - name: Install Nox
         run: |
           pip install nox
@@ -62,16 +57,45 @@ jobs:
           unzip -q iris-test-data.zip
           mkdir --parents ${GITHUB_WORKSPACE}/${IRIS_TEST_DATA_LOC_PATH}
           mv iris-test-data-${IRIS_TEST_DATA_VERSION} ${GITHUB_WORKSPACE}/${IRIS_TEST_DATA_PATH}
-          
+
       - name: Set test data var
         run: |
           echo "OVERRIDE_TEST_DATA_REPOSITORY=${GITHUB_WORKSPACE}/${IRIS_TEST_DATA_PATH}/test_data" >> $GITHUB_ENV
 
-      - name: Run CI benchmarks
+      - name: Run overnight benchmarks
+        run: |
+          first_commit=$(git log --after="$(date -d "1 day ago" +"%Y-%m-%d") 23:00:00" --pretty=format:"%h" --reverse | head -n 1)
+          nox --session="benchmarks(overnight)" .. $first_commit
+
+      - name: Create issues for performance shifts
         run: |
-          mkdir --parents benchmarks/.asv
-          set -o pipefail
-          nox --session="benchmarks(ci compare)" | tee benchmarks/.asv/ci_compare.txt
+          if [ -d .asv/performance-shifts ]
+          then
+            for commit_file in .asv/performance-shifts/*
+            do
+              pr_number=$(git log "$commit_file"^! --oneline | grep -o "#[0-9]*" | cut -c 2-)
+              author=$(gh pr view $pr_number --json author -q '.["author"]["login"]')
+              issue_title="Performance Shift(s): $commit_file"
+              issue_body="
+              Benchmark comparison has identified performance shifts at commit
+              $commit_file (#$pr_number). Please review the report below and
+              take corrective/congratulatory action as appropriate
+              :slightly_smiling_face:
+              \n
+              \n<details>
+              \n<summary>Performance shift report</summary>
+              \n
+              \n```
+              \n$(cat $commit_file)
+              \n```
+              \n
+              \n</details>
+              \n
+              \nGenerated by GHA run [`${{github.run_id}}`](https://github.com/${{github.repository}}/actions/runs/${{github.run_id}})
+              "
+              gh issue create --title $issue_title --body $issue_body --assignee $author --label "Bot" --label "Type: Performance"
+            done
+          fi
 
       - name: Archive asv results
         if: ${{ always() }}
@@ -80,4 +104,3 @@ jobs:
           name: asv-report
           path: |
             benchmarks/.asv/results
-            benchmarks/.asv/ci_compare.txt
diff --git a/noxfile.py b/noxfile.py
index 1b32ecba70..ecd587cdfa 100755
--- a/noxfile.py
+++ b/noxfile.py
@@ -344,6 +344,10 @@ def benchmarks(
     version that is also available for ``--session=tests``.
 
     """
+    # The threshold beyond which shifts are 'notable'. See `asv compare`` docs
+    #  for more.
+    COMPARE_FACTOR = 1.2
+
     session.install("asv", "nox")
     session.cd("benchmarks")
     # Skip over setup questions for a new machine.
@@ -371,11 +375,11 @@ def benchmarks(
     def asv_compare(*commits):
         """Run through a list of commits comparing each one to the next."""
         commits = [commit[:8] for commit in commits]
-        shifts_dir = Path("performance-shifts")
+        shifts_dir = Path(".asv") / "performance-shifts"
         for i in range(len(commits) - 1):
             before = commits[i]
             after = commits[i + 1]
-            asv_command_ = f"asv compare {before} {after} --factor=1.2 --split"
+            asv_command_ = f"asv compare {before} {after} --factor={COMPARE_FACTOR} --split"
             session.run(*asv_command_.split(" "))
 
             if run_type == "overnight":
@@ -387,7 +391,7 @@ def asv_compare(*commits):
                 )
                 if shifts:
                     # Write the shifts report to a file.
-                    shifts_dir.mkdir(exist_ok=True)
+                    shifts_dir.mkdir(exist_ok=True, parents=True)
                     shifts_path = shifts_dir / after
                     with shifts_path.open("w") as shifts_file:
                         shifts_file.write(shifts)

From befee3ebbe211027a236bf9d59b8cb397f1f290b Mon Sep 17 00:00:00 2001
From: Martin Yeo <martin.yeo@metoffice.gov.uk>
Date: Thu, 10 Feb 2022 23:45:42 +0000
Subject: [PATCH 04/50] GHA testing.

---
 .github/workflows/benchmark.yml | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/.github/workflows/benchmark.yml b/.github/workflows/benchmark.yml
index a12068d514..70e7e15722 100644
--- a/.github/workflows/benchmark.yml
+++ b/.github/workflows/benchmark.yml
@@ -5,11 +5,10 @@ name: benchmark-check
 on:
   # Runs every day at 23:00.
   schedule:
-    - cron: 0 23 * * *
+    - cron: 50 23 * * *
 
 jobs:
   benchmark:
-    if: "github.repository == 'SciTools/iris'"
     runs-on: ubuntu-latest
 
     env:

From 579a3e5f7ad932b4d66677f8b535eed8e7add724 Mon Sep 17 00:00:00 2001
From: Martin Yeo <40734014+trexfeathers@users.noreply.github.com>
Date: Thu, 10 Feb 2022 23:58:50 +0000
Subject: [PATCH 05/50] GHA testing

---
 .github/workflows/benchmark.yml | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/.github/workflows/benchmark.yml b/.github/workflows/benchmark.yml
index 70e7e15722..d2f8cc93ae 100644
--- a/.github/workflows/benchmark.yml
+++ b/.github/workflows/benchmark.yml
@@ -3,9 +3,9 @@
 name: benchmark-check
 
 on:
-  # Runs every day at 23:00.
-  schedule:
-    - cron: 50 23 * * *
+  push:
+    branches:
+      - overnight_benchmarks
 
 jobs:
   benchmark:

From 46f4297b4f60f29d05f793b6bad009c2ca553265 Mon Sep 17 00:00:00 2001
From: Martin Yeo <40734014+trexfeathers@users.noreply.github.com>
Date: Fri, 11 Feb 2022 00:02:03 +0000
Subject: [PATCH 06/50] Fix benchmark GHA Nox invocation.

---
 .github/workflows/benchmark.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/benchmark.yml b/.github/workflows/benchmark.yml
index d2f8cc93ae..48b14c40c0 100644
--- a/.github/workflows/benchmark.yml
+++ b/.github/workflows/benchmark.yml
@@ -64,7 +64,7 @@ jobs:
       - name: Run overnight benchmarks
         run: |
           first_commit=$(git log --after="$(date -d "1 day ago" +"%Y-%m-%d") 23:00:00" --pretty=format:"%h" --reverse | head -n 1)
-          nox --session="benchmarks(overnight)" .. $first_commit
+          nox --session="benchmarks(overnight)" -- $first_commit
 
       - name: Create issues for performance shifts
         run: |

From a1064ea28ccf5dac6ff877810405b2366e13329e Mon Sep 17 00:00:00 2001
From: Martin Yeo <40734014+trexfeathers@users.noreply.github.com>
Date: Fri, 11 Feb 2022 00:08:02 +0000
Subject: [PATCH 07/50] GHA testing.

---
 .github/workflows/benchmark.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/benchmark.yml b/.github/workflows/benchmark.yml
index 48b14c40c0..6590d30e95 100644
--- a/.github/workflows/benchmark.yml
+++ b/.github/workflows/benchmark.yml
@@ -63,7 +63,7 @@ jobs:
 
       - name: Run overnight benchmarks
         run: |
-          first_commit=$(git log --after="$(date -d "1 day ago" +"%Y-%m-%d") 23:00:00" --pretty=format:"%h" --reverse | head -n 1)
+          first_commit=$(git log --after="$(date -d "2 days ago" +"%Y-%m-%d") 23:00:00" --pretty=format:"%h" --reverse | head -n 1)
           nox --session="benchmarks(overnight)" -- $first_commit
 
       - name: Create issues for performance shifts

From d4609f82e7edc79b8f69355f506f7156290737dd Mon Sep 17 00:00:00 2001
From: Martin Yeo <40734014+trexfeathers@users.noreply.github.com>
Date: Fri, 11 Feb 2022 08:33:16 +0000
Subject: [PATCH 08/50] GHA testing.

---
 .github/workflows/benchmark.yml | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/.github/workflows/benchmark.yml b/.github/workflows/benchmark.yml
index 6590d30e95..cfe31d53ba 100644
--- a/.github/workflows/benchmark.yml
+++ b/.github/workflows/benchmark.yml
@@ -63,8 +63,8 @@ jobs:
 
       - name: Run overnight benchmarks
         run: |
-          first_commit=$(git log --after="$(date -d "2 days ago" +"%Y-%m-%d") 23:00:00" --pretty=format:"%h" --reverse | head -n 1)
-          nox --session="benchmarks(overnight)" -- $first_commit
+          first_commit=$(git log --after="$(date -d "1 day ago" +"%Y-%m-%d") 23:00:00" --pretty=format:"%h" --reverse | head -n 1)
+          nox --session="benchmarks(overnight)" -- $first_commit --quick --bench=aux_factory
 
       - name: Create issues for performance shifts
         run: |

From c50480b94594a563c7f35fa0769b20400c2b49eb Mon Sep 17 00:00:00 2001
From: Martin Yeo <40734014+trexfeathers@users.noreply.github.com>
Date: Fri, 11 Feb 2022 08:34:16 +0000
Subject: [PATCH 09/50] Benchmark GHA fetch entire Git history.

---
 .github/workflows/benchmark.yml | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/.github/workflows/benchmark.yml b/.github/workflows/benchmark.yml
index cfe31d53ba..3f30484de4 100644
--- a/.github/workflows/benchmark.yml
+++ b/.github/workflows/benchmark.yml
@@ -21,6 +21,8 @@ jobs:
     steps:
       # Checks-out your repository under $GITHUB_WORKSPACE, so your job can access it
       - uses: actions/checkout@v2
+        with:
+          fetch-depth: 0
 
       - name: Install Nox
         run: |

From eb2f2015347da3058b8e2891005819b048f3f7fd Mon Sep 17 00:00:00 2001
From: Martin Yeo <40734014+trexfeathers@users.noreply.github.com>
Date: Fri, 11 Feb 2022 08:46:25 +0000
Subject: [PATCH 10/50] GHA testing.

---
 .github/workflows/benchmark.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/benchmark.yml b/.github/workflows/benchmark.yml
index 3f30484de4..b3a2294312 100644
--- a/.github/workflows/benchmark.yml
+++ b/.github/workflows/benchmark.yml
@@ -66,7 +66,7 @@ jobs:
       - name: Run overnight benchmarks
         run: |
           first_commit=$(git log --after="$(date -d "1 day ago" +"%Y-%m-%d") 23:00:00" --pretty=format:"%h" --reverse | head -n 1)
-          nox --session="benchmarks(overnight)" -- $first_commit --quick --bench=aux_factory
+          nox --session="benchmarks(overnight)" -- $first_commit --quick --bench=aux_factory --no-interleave-rounds
 
       - name: Create issues for performance shifts
         run: |

From ac781f3e04cefa3ddca891ac24de4b044c8f0c6d Mon Sep 17 00:00:00 2001
From: Martin Yeo <40734014+trexfeathers@users.noreply.github.com>
Date: Fri, 11 Feb 2022 08:48:35 +0000
Subject: [PATCH 11/50] GHA testing.

---
 lib/iris/aux_factory.py | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/lib/iris/aux_factory.py b/lib/iris/aux_factory.py
index f49de62b3f..87349f16c0 100644
--- a/lib/iris/aux_factory.py
+++ b/lib/iris/aux_factory.py
@@ -9,6 +9,7 @@
 """
 
 from abc import ABCMeta, abstractmethod
+from time import sleep
 import warnings
 
 import cf_units
@@ -578,6 +579,8 @@ def __init__(self, delta=None, sigma=None, orography=None):
             The coordinate providing the `orog` term.
 
         """
+        # Benchmark testing.
+        sleep(10)
         # Configure the metadata manager.
         self._metadata_manager = metadata_manager_factory(CoordMetadata)
         super().__init__()

From 56e13e1aae7ef89e28609c478c0a25dd83eaa907 Mon Sep 17 00:00:00 2001
From: Martin Yeo <40734014+trexfeathers@users.noreply.github.com>
Date: Fri, 11 Feb 2022 08:56:56 +0000
Subject: [PATCH 12/50] GHA benchmarks correct directory.

---
 .github/workflows/benchmark.yml | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/.github/workflows/benchmark.yml b/.github/workflows/benchmark.yml
index b3a2294312..1c9da3f9c9 100644
--- a/.github/workflows/benchmark.yml
+++ b/.github/workflows/benchmark.yml
@@ -70,9 +70,9 @@ jobs:
 
       - name: Create issues for performance shifts
         run: |
-          if [ -d .asv/performance-shifts ]
+          if [ -d benchmarks/.asv/performance-shifts ]
           then
-            for commit_file in .asv/performance-shifts/*
+            for commit_file in benchmarks/.asv/performance-shifts/*
             do
               pr_number=$(git log "$commit_file"^! --oneline | grep -o "#[0-9]*" | cut -c 2-)
               author=$(gh pr view $pr_number --json author -q '.["author"]["login"]')

From 9245cb3a0806a5d75405dfb2b855d6fb6afc02e6 Mon Sep 17 00:00:00 2001
From: Martin Yeo <40734014+trexfeathers@users.noreply.github.com>
Date: Fri, 11 Feb 2022 09:05:29 +0000
Subject: [PATCH 13/50] Benchmark GHA authenticate GH CLI.

---
 .github/workflows/benchmark.yml | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/.github/workflows/benchmark.yml b/.github/workflows/benchmark.yml
index 1c9da3f9c9..e802c77bf1 100644
--- a/.github/workflows/benchmark.yml
+++ b/.github/workflows/benchmark.yml
@@ -69,6 +69,8 @@ jobs:
           nox --session="benchmarks(overnight)" -- $first_commit --quick --bench=aux_factory --no-interleave-rounds
 
       - name: Create issues for performance shifts
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
         run: |
           if [ -d benchmarks/.asv/performance-shifts ]
           then
@@ -94,7 +96,7 @@ jobs:
               \n
               \nGenerated by GHA run [`${{github.run_id}}`](https://github.com/${{github.repository}}/actions/runs/${{github.run_id}})
               "
-              gh issue create --title $issue_title --body $issue_body --assignee $author --label "Bot" --label "Type: Performance"
+              gh issue create --title $issue_title --body $issue_body --assignee $author --label "Bot" --label "Type: Performance" --repo $GITHUB_REPOSITORY
             done
           fi
 

From 06165e99339caad2ff5e594b863b49f2e8aaaa62 Mon Sep 17 00:00:00 2001
From: Martin Yeo <40734014+trexfeathers@users.noreply.github.com>
Date: Fri, 11 Feb 2022 09:06:15 +0000
Subject: [PATCH 14/50] GHA testing.

---
 .github/workflows/benchmark.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/benchmark.yml b/.github/workflows/benchmark.yml
index e802c77bf1..06d6e2f84d 100644
--- a/.github/workflows/benchmark.yml
+++ b/.github/workflows/benchmark.yml
@@ -65,7 +65,7 @@ jobs:
 
       - name: Run overnight benchmarks
         run: |
-          first_commit=$(git log --after="$(date -d "1 day ago" +"%Y-%m-%d") 23:00:00" --pretty=format:"%h" --reverse | head -n 1)
+          first_commit=c50480b94594a563c7f35fa0769b20400c2b49eb
           nox --session="benchmarks(overnight)" -- $first_commit --quick --bench=aux_factory --no-interleave-rounds
 
       - name: Create issues for performance shifts

From 3b4003a67965876a7406ca9413e58b1a479981d8 Mon Sep 17 00:00:00 2001
From: Martin Yeo <40734014+trexfeathers@users.noreply.github.com>
Date: Fri, 11 Feb 2022 09:12:26 +0000
Subject: [PATCH 15/50] GHA testing.

---
 lib/iris/aux_factory.py | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/lib/iris/aux_factory.py b/lib/iris/aux_factory.py
index 87349f16c0..f49de62b3f 100644
--- a/lib/iris/aux_factory.py
+++ b/lib/iris/aux_factory.py
@@ -9,7 +9,6 @@
 """
 
 from abc import ABCMeta, abstractmethod
-from time import sleep
 import warnings
 
 import cf_units
@@ -579,8 +578,6 @@ def __init__(self, delta=None, sigma=None, orography=None):
             The coordinate providing the `orog` term.
 
         """
-        # Benchmark testing.
-        sleep(10)
         # Configure the metadata manager.
         self._metadata_manager = metadata_manager_factory(CoordMetadata)
         super().__init__()

From f4bd66e6811e351e15891b0102038d20545f607c Mon Sep 17 00:00:00 2001
From: Martin Yeo <40734014+trexfeathers@users.noreply.github.com>
Date: Fri, 11 Feb 2022 09:13:33 +0000
Subject: [PATCH 16/50] Benchmark GHA cd into performance-shifts.

---
 .github/workflows/benchmark.yml | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/.github/workflows/benchmark.yml b/.github/workflows/benchmark.yml
index 06d6e2f84d..3857a667a5 100644
--- a/.github/workflows/benchmark.yml
+++ b/.github/workflows/benchmark.yml
@@ -74,7 +74,8 @@ jobs:
         run: |
           if [ -d benchmarks/.asv/performance-shifts ]
           then
-            for commit_file in benchmarks/.asv/performance-shifts/*
+            cd benchmarks/.asv/performance-shifts
+            for commit_file in .*
             do
               pr_number=$(git log "$commit_file"^! --oneline | grep -o "#[0-9]*" | cut -c 2-)
               author=$(gh pr view $pr_number --json author -q '.["author"]["login"]')

From 5cd35c86efce948b083b44bb7761f292c008a825 Mon Sep 17 00:00:00 2001
From: Martin Yeo <40734014+trexfeathers@users.noreply.github.com>
Date: Fri, 11 Feb 2022 09:50:11 +0000
Subject: [PATCH 17/50] GHA testing.

---
 .github/workflows/benchmark.yml | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/.github/workflows/benchmark.yml b/.github/workflows/benchmark.yml
index 3857a667a5..df34fa082a 100644
--- a/.github/workflows/benchmark.yml
+++ b/.github/workflows/benchmark.yml
@@ -77,8 +77,8 @@ jobs:
             cd benchmarks/.asv/performance-shifts
             for commit_file in .*
             do
-              pr_number=$(git log "$commit_file"^! --oneline | grep -o "#[0-9]*" | cut -c 2-)
-              author=$(gh pr view $pr_number --json author -q '.["author"]["login"]')
+              pr_number=$(git log 8404ff64^! --oneline | grep -o "#[0-9]*" | cut -c 2-)
+              author=$(gh pr view $pr_number --json author -q '.["author"]["login"]' --repo SciTools/iris)
               issue_title="Performance Shift(s): $commit_file"
               issue_body="
               Benchmark comparison has identified performance shifts at commit

From 51fd2010e6753cb08ac181a866b92780c9ff29e0 Mon Sep 17 00:00:00 2001
From: Martin Yeo <40734014+trexfeathers@users.noreply.github.com>
Date: Fri, 11 Feb 2022 10:00:14 +0000
Subject: [PATCH 18/50] Benchmarks GHA correct file iteration.

---
 .github/workflows/benchmark.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/benchmark.yml b/.github/workflows/benchmark.yml
index df34fa082a..eddd2b18c4 100644
--- a/.github/workflows/benchmark.yml
+++ b/.github/workflows/benchmark.yml
@@ -75,7 +75,7 @@ jobs:
           if [ -d benchmarks/.asv/performance-shifts ]
           then
             cd benchmarks/.asv/performance-shifts
-            for commit_file in .*
+            for commit_file in *
             do
               pr_number=$(git log 8404ff64^! --oneline | grep -o "#[0-9]*" | cut -c 2-)
               author=$(gh pr view $pr_number --json author -q '.["author"]["login"]' --repo SciTools/iris)

From a22da0df54c947b027858a78af27fec285226c86 Mon Sep 17 00:00:00 2001
From: Martin Yeo <40734014+trexfeathers@users.noreply.github.com>
Date: Fri, 11 Feb 2022 10:13:59 +0000
Subject: [PATCH 19/50] GHA testing.

---
 .github/workflows/benchmark.yml | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/.github/workflows/benchmark.yml b/.github/workflows/benchmark.yml
index eddd2b18c4..7349b0a694 100644
--- a/.github/workflows/benchmark.yml
+++ b/.github/workflows/benchmark.yml
@@ -66,7 +66,7 @@ jobs:
       - name: Run overnight benchmarks
         run: |
           first_commit=c50480b94594a563c7f35fa0769b20400c2b49eb
-          nox --session="benchmarks(overnight)" -- $first_commit --quick --bench=aux_factory --no-interleave-rounds
+          nox --session="benchmarks(overnight)" -- $first_commit --quick --bench=aux_factory --no-interleave-rounds --steps 3
 
       - name: Create issues for performance shifts
         env:
@@ -78,7 +78,7 @@ jobs:
             for commit_file in *
             do
               pr_number=$(git log 8404ff64^! --oneline | grep -o "#[0-9]*" | cut -c 2-)
-              author=$(gh pr view $pr_number --json author -q '.["author"]["login"]' --repo SciTools/iris)
+              author=trexfeathers
               issue_title="Performance Shift(s): $commit_file"
               issue_body="
               Benchmark comparison has identified performance shifts at commit

From 98472b51cfaff626e496435b5f9bd30740eaf8ff Mon Sep 17 00:00:00 2001
From: Martin Yeo <40734014+trexfeathers@users.noreply.github.com>
Date: Fri, 11 Feb 2022 10:18:00 +0000
Subject: [PATCH 20/50] GHA testing.

---
 .github/workflows/benchmark.yml | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/.github/workflows/benchmark.yml b/.github/workflows/benchmark.yml
index 7349b0a694..73ea4b10c4 100644
--- a/.github/workflows/benchmark.yml
+++ b/.github/workflows/benchmark.yml
@@ -65,8 +65,8 @@ jobs:
 
       - name: Run overnight benchmarks
         run: |
-          first_commit=c50480b94594a563c7f35fa0769b20400c2b49eb
-          nox --session="benchmarks(overnight)" -- $first_commit --quick --bench=aux_factory --no-interleave-rounds --steps 3
+          first_commit=06165e99339caad2ff5e594b863b49f2e8aaaa62
+          nox --session="benchmarks(overnight)" -- $first_commit --quick --bench=aux_factory --no-interleave-rounds
 
       - name: Create issues for performance shifts
         env:

From aee75074a55588598bc5f41ef74d706232cfa300 Mon Sep 17 00:00:00 2001
From: Martin Yeo <40734014+trexfeathers@users.noreply.github.com>
Date: Fri, 11 Feb 2022 10:23:37 +0000
Subject: [PATCH 21/50] GHA testing.

---
 .github/workflows/benchmark.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/benchmark.yml b/.github/workflows/benchmark.yml
index 73ea4b10c4..b24784436d 100644
--- a/.github/workflows/benchmark.yml
+++ b/.github/workflows/benchmark.yml
@@ -75,6 +75,7 @@ jobs:
           if [ -d benchmarks/.asv/performance-shifts ]
           then
             cd benchmarks/.asv/performance-shifts
+            ls *
             for commit_file in *
             do
               pr_number=$(git log 8404ff64^! --oneline | grep -o "#[0-9]*" | cut -c 2-)
@@ -97,7 +98,6 @@ jobs:
               \n
               \nGenerated by GHA run [`${{github.run_id}}`](https://github.com/${{github.repository}}/actions/runs/${{github.run_id}})
               "
-              gh issue create --title $issue_title --body $issue_body --assignee $author --label "Bot" --label "Type: Performance" --repo $GITHUB_REPOSITORY
             done
           fi
 

From 906d5f15a4dcf908c80ff882e62cad4e4f3f93ff Mon Sep 17 00:00:00 2001
From: Martin Yeo <40734014+trexfeathers@users.noreply.github.com>
Date: Fri, 11 Feb 2022 10:29:49 +0000
Subject: [PATCH 22/50] GHA testing.

---
 .github/workflows/benchmark.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/benchmark.yml b/.github/workflows/benchmark.yml
index b24784436d..76ff0a621e 100644
--- a/.github/workflows/benchmark.yml
+++ b/.github/workflows/benchmark.yml
@@ -75,7 +75,6 @@ jobs:
           if [ -d benchmarks/.asv/performance-shifts ]
           then
             cd benchmarks/.asv/performance-shifts
-            ls *
             for commit_file in *
             do
               pr_number=$(git log 8404ff64^! --oneline | grep -o "#[0-9]*" | cut -c 2-)
@@ -98,6 +97,7 @@ jobs:
               \n
               \nGenerated by GHA run [`${{github.run_id}}`](https://github.com/${{github.repository}}/actions/runs/${{github.run_id}})
               "
+              echo -e $issue_body
             done
           fi
 

From c14f748ff85b6a7e4797c01a11739c0fdebe0c26 Mon Sep 17 00:00:00 2001
From: Martin Yeo <40734014+trexfeathers@users.noreply.github.com>
Date: Fri, 11 Feb 2022 10:38:02 +0000
Subject: [PATCH 23/50] GHA testing.

---
 .github/workflows/benchmark.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/benchmark.yml b/.github/workflows/benchmark.yml
index 76ff0a621e..149bfb9385 100644
--- a/.github/workflows/benchmark.yml
+++ b/.github/workflows/benchmark.yml
@@ -79,7 +79,7 @@ jobs:
             do
               pr_number=$(git log 8404ff64^! --oneline | grep -o "#[0-9]*" | cut -c 2-)
               author=trexfeathers
-              issue_title="Performance Shift(s): $commit_file"
+              issue_title="Performance Shift(s): $(echo $commit_file)"
               issue_body="
               Benchmark comparison has identified performance shifts at commit
               $commit_file (#$pr_number). Please review the report below and

From d695484406803f3ca2c2163859ccba7b930377c8 Mon Sep 17 00:00:00 2001
From: Martin Yeo <40734014+trexfeathers@users.noreply.github.com>
Date: Fri, 11 Feb 2022 10:40:45 +0000
Subject: [PATCH 24/50] GHA testing.

---
 .github/workflows/benchmark.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/benchmark.yml b/.github/workflows/benchmark.yml
index 149bfb9385..e4cddc14b4 100644
--- a/.github/workflows/benchmark.yml
+++ b/.github/workflows/benchmark.yml
@@ -82,7 +82,7 @@ jobs:
               issue_title="Performance Shift(s): $(echo $commit_file)"
               issue_body="
               Benchmark comparison has identified performance shifts at commit
-              $commit_file (#$pr_number). Please review the report below and
+              $(echo $commit_file) (#$pr_number). Please review the report below and
               take corrective/congratulatory action as appropriate
               :slightly_smiling_face:
               \n

From 616f4f512a9f71e290da7dd83b3b26cbceeb410e Mon Sep 17 00:00:00 2001
From: Martin Yeo <40734014+trexfeathers@users.noreply.github.com>
Date: Fri, 11 Feb 2022 10:54:31 +0000
Subject: [PATCH 25/50] GHA testing.

---
 .github/workflows/benchmark.yml | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/.github/workflows/benchmark.yml b/.github/workflows/benchmark.yml
index e4cddc14b4..4f587bf6fc 100644
--- a/.github/workflows/benchmark.yml
+++ b/.github/workflows/benchmark.yml
@@ -89,9 +89,9 @@ jobs:
               \n<details>
               \n<summary>Performance shift report</summary>
               \n
-              \n```
+              \n\`\`\`
               \n$(cat $commit_file)
-              \n```
+              \n\`\`\`
               \n
               \n</details>
               \n

From ed28ffcc536db8bcbe3cb3449c5af9df0e35c9ca Mon Sep 17 00:00:00 2001
From: Martin Yeo <40734014+trexfeathers@users.noreply.github.com>
Date: Fri, 11 Feb 2022 11:42:52 +0000
Subject: [PATCH 26/50] GHA benchmark escape backticks.

---
 .github/workflows/benchmark.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/benchmark.yml b/.github/workflows/benchmark.yml
index 4f587bf6fc..a943835679 100644
--- a/.github/workflows/benchmark.yml
+++ b/.github/workflows/benchmark.yml
@@ -95,7 +95,7 @@ jobs:
               \n
               \n</details>
               \n
-              \nGenerated by GHA run [`${{github.run_id}}`](https://github.com/${{github.repository}}/actions/runs/${{github.run_id}})
+              \nGenerated by GHA run [\`${{github.run_id}}\`](https://github.com/${{github.repository}}/actions/runs/${{github.run_id}})
               "
               echo -e $issue_body
             done

From 5dc7b707c58367761430d2eedbc3524beda142b5 Mon Sep 17 00:00:00 2001
From: Martin Yeo <40734014+trexfeathers@users.noreply.github.com>
Date: Fri, 11 Feb 2022 11:57:06 +0000
Subject: [PATCH 27/50] Benchmark GHA restore behaviour after testing.

---
 .github/workflows/benchmark.yml | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/.github/workflows/benchmark.yml b/.github/workflows/benchmark.yml
index a943835679..c761064a89 100644
--- a/.github/workflows/benchmark.yml
+++ b/.github/workflows/benchmark.yml
@@ -78,11 +78,11 @@ jobs:
             for commit_file in *
             do
               pr_number=$(git log 8404ff64^! --oneline | grep -o "#[0-9]*" | cut -c 2-)
-              author=trexfeathers
-              issue_title="Performance Shift(s): $(echo $commit_file)"
-              issue_body="
+              assignee=$(gh pr view $pr_number --json author -q '.["author"]["login"]' --repo SciTools/iris)
+              title="Performance Shift(s): $commit_file"
+              body="
               Benchmark comparison has identified performance shifts at commit
-              $(echo $commit_file) (#$pr_number). Please review the report below and
+              $commit_file (#$pr_number). Please review the report below and
               take corrective/congratulatory action as appropriate
               :slightly_smiling_face:
               \n
@@ -97,7 +97,7 @@ jobs:
               \n
               \nGenerated by GHA run [\`${{github.run_id}}\`](https://github.com/${{github.repository}}/actions/runs/${{github.run_id}})
               "
-              echo -e $issue_body
+              gh issue create --title $title --body $body --assignee $assignee --label "Bot" --label "Type: Performance" --repo $GITHUB_REPOSITORY
             done
           fi
 

From f18673a1f413b26f297490f8a2e767d5b091c26e Mon Sep 17 00:00:00 2001
From: Martin Yeo <40734014+trexfeathers@users.noreply.github.com>
Date: Fri, 11 Feb 2022 12:05:08 +0000
Subject: [PATCH 28/50] Benchmark GHA correct string wrapping.

---
 .github/workflows/benchmark.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/benchmark.yml b/.github/workflows/benchmark.yml
index c761064a89..5fb51b1a7b 100644
--- a/.github/workflows/benchmark.yml
+++ b/.github/workflows/benchmark.yml
@@ -97,7 +97,7 @@ jobs:
               \n
               \nGenerated by GHA run [\`${{github.run_id}}\`](https://github.com/${{github.repository}}/actions/runs/${{github.run_id}})
               "
-              gh issue create --title $title --body $body --assignee $assignee --label "Bot" --label "Type: Performance" --repo $GITHUB_REPOSITORY
+              gh issue create --title "$title" --body "$body" --assignee $assignee --label "Bot" --label "Type: Performance" --repo $GITHUB_REPOSITORY
             done
           fi
 

From 3104a3c2ef5699b149ddd40c0074dcd7af3f8b68 Mon Sep 17 00:00:00 2001
From: Martin Yeo <40734014+trexfeathers@users.noreply.github.com>
Date: Fri, 11 Feb 2022 12:26:16 +0000
Subject: [PATCH 29/50] Benchmark GHA better string formatting.

---
 .github/workflows/benchmark.yml | 30 +++++++++++++++---------------
 1 file changed, 15 insertions(+), 15 deletions(-)

diff --git a/.github/workflows/benchmark.yml b/.github/workflows/benchmark.yml
index 5fb51b1a7b..f6b2ae4e39 100644
--- a/.github/workflows/benchmark.yml
+++ b/.github/workflows/benchmark.yml
@@ -81,21 +81,21 @@ jobs:
               assignee=$(gh pr view $pr_number --json author -q '.["author"]["login"]' --repo SciTools/iris)
               title="Performance Shift(s): $commit_file"
               body="
-              Benchmark comparison has identified performance shifts at commit
-              $commit_file (#$pr_number). Please review the report below and
-              take corrective/congratulatory action as appropriate
-              :slightly_smiling_face:
-              \n
-              \n<details>
-              \n<summary>Performance shift report</summary>
-              \n
-              \n\`\`\`
-              \n$(cat $commit_file)
-              \n\`\`\`
-              \n
-              \n</details>
-              \n
-              \nGenerated by GHA run [\`${{github.run_id}}\`](https://github.com/${{github.repository}}/actions/runs/${{github.run_id}})
+          Benchmark comparison has identified performance shifts at commit
+          $commit_file (#$pr_number). Please review the report below and
+          take corrective/congratulatory action as appropriate
+          :slightly_smiling_face:
+          
+          <details>
+          <summary>Performance shift report</summary>
+          
+          \`\`\`
+          $(cat $commit_file)
+          \`\`\`
+          
+          </details>
+          
+          Generated by GHA run [\`${{github.run_id}}\`](https://github.com/${{github.repository}}/actions/runs/${{github.run_id}})
               "
               gh issue create --title "$title" --body "$body" --assignee $assignee --label "Bot" --label "Type: Performance" --repo $GITHUB_REPOSITORY
             done

From b631eededfd701db8e35fd29aa551646c5e16d5f Mon Sep 17 00:00:00 2001
From: Martin Yeo <40734014+trexfeathers@users.noreply.github.com>
Date: Fri, 11 Feb 2022 12:35:17 +0000
Subject: [PATCH 30/50] GHA benchmark more issue formatting.

---
 .github/workflows/benchmark.yml | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/.github/workflows/benchmark.yml b/.github/workflows/benchmark.yml
index f6b2ae4e39..19a2ac5635 100644
--- a/.github/workflows/benchmark.yml
+++ b/.github/workflows/benchmark.yml
@@ -79,11 +79,11 @@ jobs:
             do
               pr_number=$(git log 8404ff64^! --oneline | grep -o "#[0-9]*" | cut -c 2-)
               assignee=$(gh pr view $pr_number --json author -q '.["author"]["login"]' --repo SciTools/iris)
-              title="Performance Shift(s): $commit_file"
+              title="Performance Shift(s): \`$commit_file\`"
               body="
-          Benchmark comparison has identified performance shifts at commit
-          $commit_file (#$pr_number). Please review the report below and
-          take corrective/congratulatory action as appropriate
+          Benchmark comparison has identified performance shifts at commit\
+          $commit_file (#$pr_number). Please review the report below and\
+          take corrective/congratulatory action as appropriate\
           :slightly_smiling_face:
           
           <details>

From 8683bad2b48affc55f7c326fff6d263e1971f3b2 Mon Sep 17 00:00:00 2001
From: Martin Yeo <martin.yeo@metoffice.gov.uk>
Date: Fri, 11 Feb 2022 13:13:38 +0000
Subject: [PATCH 31/50] Benchmark GHA restore correct settings after testing.

---
 .github/workflows/benchmark.yml | 23 ++++++++++++-----------
 1 file changed, 12 insertions(+), 11 deletions(-)

diff --git a/.github/workflows/benchmark.yml b/.github/workflows/benchmark.yml
index 19a2ac5635..8ba856f0e0 100644
--- a/.github/workflows/benchmark.yml
+++ b/.github/workflows/benchmark.yml
@@ -3,12 +3,13 @@
 name: benchmark-check
 
 on:
-  push:
-    branches:
-      - overnight_benchmarks
+  schedule:
+    # Runs every day at 23:00.
+    - cron: 0 23 * * *
 
 jobs:
   benchmark:
+    if: "github.repository == 'SciTools/iris'"
     runs-on: ubuntu-latest
 
     env:
@@ -65,8 +66,8 @@ jobs:
 
       - name: Run overnight benchmarks
         run: |
-          first_commit=06165e99339caad2ff5e594b863b49f2e8aaaa62
-          nox --session="benchmarks(overnight)" -- $first_commit --quick --bench=aux_factory --no-interleave-rounds
+          first_commit=$(git log --after="$(date -d "1 day ago" +"%Y-%m-%d") 23:00:00" --pretty=format:"%h" --reverse | head -n 1)
+          nox --session="benchmarks(overnight)" .. $first_commit
 
       - name: Create issues for performance shifts
         env:
@@ -77,24 +78,24 @@ jobs:
             cd benchmarks/.asv/performance-shifts
             for commit_file in *
             do
-              pr_number=$(git log 8404ff64^! --oneline | grep -o "#[0-9]*" | cut -c 2-)
-              assignee=$(gh pr view $pr_number --json author -q '.["author"]["login"]' --repo SciTools/iris)
+              pr_number=$(git log "$commit_file"^! --oneline | grep -o "#[0-9]*" | cut -c 2-)
+              assignee=$(gh pr view $pr_number --json author -q '.["author"]["login"]' --repo $GITHUB_REPOSITORY)
               title="Performance Shift(s): \`$commit_file\`"
               body="
           Benchmark comparison has identified performance shifts at commit\
           $commit_file (#$pr_number). Please review the report below and\
           take corrective/congratulatory action as appropriate\
           :slightly_smiling_face:
-          
+
           <details>
           <summary>Performance shift report</summary>
-          
+
           \`\`\`
           $(cat $commit_file)
           \`\`\`
-          
+
           </details>
-          
+
           Generated by GHA run [\`${{github.run_id}}\`](https://github.com/${{github.repository}}/actions/runs/${{github.run_id}})
               "
               gh issue create --title "$title" --body "$body" --assignee $assignee --label "Bot" --label "Type: Performance" --repo $GITHUB_REPOSITORY

From b82b84601c7c59a837156c0f26c9bf1577231048 Mon Sep 17 00:00:00 2001
From: Martin Yeo <martin.yeo@metoffice.gov.uk>
Date: Fri, 11 Feb 2022 13:14:58 +0000
Subject: [PATCH 32/50] Benchmark GHA minor improvements.

---
 .github/workflows/benchmark.yml | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/.github/workflows/benchmark.yml b/.github/workflows/benchmark.yml
index 8ba856f0e0..b4c2063156 100644
--- a/.github/workflows/benchmark.yml
+++ b/.github/workflows/benchmark.yml
@@ -66,7 +66,7 @@ jobs:
 
       - name: Run overnight benchmarks
         run: |
-          first_commit=$(git log --after="$(date -d "1 day ago" +"%Y-%m-%d") 23:00:00" --pretty=format:"%h" --reverse | head -n 1)
+          first_commit=$(git log --after="$(date -d "1 day ago" +"%Y-%m-%d") 23:00:00" --pretty=format:"%h" | tail -n 1)
           nox --session="benchmarks(overnight)" .. $first_commit
 
       - name: Create issues for performance shifts
@@ -82,9 +82,9 @@ jobs:
               assignee=$(gh pr view $pr_number --json author -q '.["author"]["login"]' --repo $GITHUB_REPOSITORY)
               title="Performance Shift(s): \`$commit_file\`"
               body="
-          Benchmark comparison has identified performance shifts at commit\
-          $commit_file (#$pr_number). Please review the report below and\
-          take corrective/congratulatory action as appropriate\
+          Benchmark comparison has identified performance shifts at commit \
+          $commit_file (#$pr_number). Please review the report below and \
+          take corrective/congratulatory action as appropriate \
           :slightly_smiling_face:
 
           <details>

From f35f15a42750375a9f5aaf5cdf5a704a2347ff04 Mon Sep 17 00:00:00 2001
From: Martin Yeo <martin.yeo@metoffice.gov.uk>
Date: Fri, 11 Feb 2022 13:17:42 +0000
Subject: [PATCH 33/50] Nox correct posargs syntax.

---
 .github/workflows/benchmark.yml | 2 +-
 noxfile.py                      | 8 ++++----
 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/.github/workflows/benchmark.yml b/.github/workflows/benchmark.yml
index b4c2063156..935686befb 100644
--- a/.github/workflows/benchmark.yml
+++ b/.github/workflows/benchmark.yml
@@ -67,7 +67,7 @@ jobs:
       - name: Run overnight benchmarks
         run: |
           first_commit=$(git log --after="$(date -d "1 day ago" +"%Y-%m-%d") 23:00:00" --pretty=format:"%h" | tail -n 1)
-          nox --session="benchmarks(overnight)" .. $first_commit
+          nox --session="benchmarks(overnight)" -- $first_commit
 
       - name: Create issues for performance shifts
         env:
diff --git a/noxfile.py b/noxfile.py
index ecd587cdfa..b8d46a7e95 100755
--- a/noxfile.py
+++ b/noxfile.py
@@ -332,10 +332,10 @@ def benchmarks(
 
     Examples
     --------
-    * ``nox --session="benchmarks(overnight)" .. a1b23d4``
-    * ``nox --session="benchmarks(branch)" .. upstream/main``
-    * ``nox --session="benchmarks(branch)" .. upstream/main --bench=regridding``
-    * ``nox --session="benchmarks(custom)" .. continuous a1b23d4 HEAD --quick``
+    * ``nox --session="benchmarks(overnight)" -- a1b23d4``
+    * ``nox --session="benchmarks(branch)" -- upstream/main``
+    * ``nox --session="benchmarks(branch)" -- upstream/main --bench=regridding``
+    * ``nox --session="benchmarks(custom)" -- continuous a1b23d4 HEAD --quick``
 
     Notes
     -----

From 807c35c0518b1297179da71aec4d0d2bd0307730 Mon Sep 17 00:00:00 2001
From: Martin Yeo <martin.yeo@metoffice.gov.uk>
Date: Fri, 11 Feb 2022 13:19:06 +0000
Subject: [PATCH 34/50] Remove Nox benchmarks session outdated note about
 environments.

---
 noxfile.py | 6 ------
 1 file changed, 6 deletions(-)

diff --git a/noxfile.py b/noxfile.py
index b8d46a7e95..eeeca706dc 100755
--- a/noxfile.py
+++ b/noxfile.py
@@ -337,12 +337,6 @@ def benchmarks(
     * ``nox --session="benchmarks(branch)" -- upstream/main --bench=regridding``
     * ``nox --session="benchmarks(custom)" -- continuous a1b23d4 HEAD --quick``
 
-    Notes
-    -----
-    ASV is set up to use ``nox --session=tests --install-only`` to prepare
-    the benchmarking environment. This session environment must use a Python
-    version that is also available for ``--session=tests``.
-
     """
     # The threshold beyond which shifts are 'notable'. See `asv compare`` docs
     #  for more.

From 4d856f9af3fc3fc1da16127c1a8786c2766a2438 Mon Sep 17 00:00:00 2001
From: Martin Yeo <martin.yeo@metoffice.gov.uk>
Date: Fri, 11 Feb 2022 13:20:17 +0000
Subject: [PATCH 35/50] Nox correct posargs syntax.

---
 noxfile.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/noxfile.py b/noxfile.py
index eeeca706dc..85a98cd2f8 100755
--- a/noxfile.py
+++ b/noxfile.py
@@ -305,7 +305,7 @@ def benchmarks(
     Perform esmf-regrid performance benchmarks (using Airspeed Velocity).
 
     All run types require a single Nox positional argument (e.g.
-    ``nox --session="foo" .. my_pos_arg``) - detailed in the parameters
+    ``nox --session="foo" -- my_pos_arg``) - detailed in the parameters
     section - and can optionally accept a series of further arguments that will
     be added to session's ASV command.
 

From 54cee4a06c0a10ec3d78b919ceb4470345798c41 Mon Sep 17 00:00:00 2001
From: Martin Yeo <martin.yeo@metoffice.gov.uk>
Date: Fri, 11 Feb 2022 15:18:12 +0000
Subject: [PATCH 36/50] Benchmarks README.

---
 benchmarks/README.md | 70 ++++++++++++++++++++++++++++++++++++++++++++
 noxfile.py           |  3 +-
 2 files changed, 72 insertions(+), 1 deletion(-)
 create mode 100644 benchmarks/README.md

diff --git a/benchmarks/README.md b/benchmarks/README.md
new file mode 100644
index 0000000000..84538463bc
--- /dev/null
+++ b/benchmarks/README.md
@@ -0,0 +1,70 @@
+[//]: # (the final pieces of this setup are still falling into place, so have
+         included several TODO's)
+
+# Iris Performance Benchmarking
+
+Iris uses an [Airspeed Velocity](https://github.com/airspeed-velocity/asv)
+(ASV) setup to benchmark performance. This is primarily designed to check for
+performance shifts between commits using statistical analysis, but can also
+be easily repurposed for manual comparative and scalability analyses.
+
+The benchmarks are automatically run overnight
+[by a GitHub Action](../.github/workflows/benchmark.yml), with any notable
+shifts in performance being flagged in a new GitHub issue.
+
+## Running benchmarks
+
+`asv ...` commands must be run from this directory. You will need to have ASV
+installed, as well as Nox (see 
+[Benchmark environments](#benchmark-environments)).
+
+[Iris' noxfile](../noxfile.py) includes a `benchmarks` session that provides
+conveniences for setting up, and even replicating the automated overnight run
+locally. See the session docstring for detail.
+
+[//]: # (TODO: ### Environment variables section)
+
+## Writing benchmarks
+
+[//]: # (TODO: ### Data generation section)
+
+[See the ASV docs](https://asv.readthedocs.io/) for full detail.
+
+### ASV re-run behaviour
+
+Note that ASV re-runs a benchmark multiple times between its `setup()` routine.
+This is a problem for benchmarking certain Iris operations such as data
+realisation, since the data will no longer be lazy after the first run.
+Consider writing extra steps to restore objects' original state _within_ the
+benchmark itself.
+
+If adding steps to the benchmark will skew the result too much then re-running
+can be disabled by setting an attribute on the benchmark: `number = 1`. To
+maintain result accuracy this should be accompanied by increasing the number of
+repeats _between_ `setup()` calls using the `repeat` attribute.
+`warmup_time = 0` is also advisable since ASV performs independent re-runs to
+estimate run-time, and these will still be subject to the original problem.
+
+### Scaling / non-Scaling Performance Differences
+
+When comparing performance between commits/file-type/whatever it can be helpful
+to know if the differences exist in scaling or non-scaling parts of the Iris
+functionality in question. This can be done using a size parameter, setting
+one value to be as small as possible (e.g. a scalar `Cube`), and the other to
+be significantly larger (e.g. a 1000x1000 `Cube`). Performance differences
+might only be seen for the larger value, or the smaller, or both, getting you
+closer to the root cause.
+
+## Benchmark environments
+
+We have disabled ASV's standard environment management, instead using an
+environment built using the same Nox scripts as Iris' test environments. This
+is done using ASV's plugin architecture - see
+[asv_delegated_conda.py](asv_delegated_conda.py) and the extra config items in
+[asv.conf.json](asv.conf.json).
+
+(ASV is written to control the environment(s) that benchmarks are run in -
+minimising external factors and also allowing it to compare between a matrix
+of dependencies (each in a separate environment). We have chosen to sacrifice
+these features in favour of testing each commit with its intended dependencies,
+controlled by Nox + lock-files).
diff --git a/noxfile.py b/noxfile.py
index 85a98cd2f8..fe998e464a 100755
--- a/noxfile.py
+++ b/noxfile.py
@@ -302,7 +302,7 @@ def benchmarks(
     run_type: Literal["overnight", "branch", "custom"],
 ):
     """
-    Perform esmf-regrid performance benchmarks (using Airspeed Velocity).
+    Perform Iris performance benchmarks (using Airspeed Velocity).
 
     All run types require a single Nox positional argument (e.g.
     ``nox --session="foo" -- my_pos_arg``) - detailed in the parameters
@@ -334,6 +334,7 @@ def benchmarks(
     --------
     * ``nox --session="benchmarks(overnight)" -- a1b23d4``
     * ``nox --session="benchmarks(branch)" -- upstream/main``
+    * ``nox --session="benchmarks(branch)" -- upstream/mesh-data-model``
     * ``nox --session="benchmarks(branch)" -- upstream/main --bench=regridding``
     * ``nox --session="benchmarks(custom)" -- continuous a1b23d4 HEAD --quick``
 

From 3861678de290175dd20e0f4ff6849abd68502229 Mon Sep 17 00:00:00 2001
From: Martin Yeo <martin.yeo@metoffice.gov.uk>
Date: Fri, 11 Feb 2022 15:33:57 +0000
Subject: [PATCH 37/50] Nox benchmarks session note about accuracy and runtime.

---
 noxfile.py | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/noxfile.py b/noxfile.py
index fe998e464a..48f4218e5e 100755
--- a/noxfile.py
+++ b/noxfile.py
@@ -325,6 +325,8 @@ def benchmarks(
           Designed for testing if the active branch's changes cause performance
           shifts - anticipating what would be caught by ``overnight`` once
           merged.
+          **For maximum accuracy, avoid using the machine that is running this
+          session. Run time could be >1 hour for the full benchmark suite.**
         * ``custom``: run ASV with the input **ASV command type**, without any
           preset arguments - must all be supplied by the user. So just like
           running ASV manually, with the convenience of re-using the session's

From 340b97561193fe5ba2d3805b9392ce688ef87cfd Mon Sep 17 00:00:00 2001
From: Martin Yeo <martin.yeo@metoffice.gov.uk>
Date: Fri, 11 Feb 2022 16:07:09 +0000
Subject: [PATCH 38/50] Benchmarks Nox improved posargs handling.

---
 noxfile.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/noxfile.py b/noxfile.py
index 48f4218e5e..c49aba8bc0 100755
--- a/noxfile.py
+++ b/noxfile.py
@@ -359,13 +359,13 @@ def benchmarks(
     if run_type not in run_type_arg.keys():
         message = f"Unsupported run-type: {run_type}"
         raise NotImplementedError(message)
-    first_arg = session.posargs[0]
-    if not first_arg:
+    if not session.posargs:
         message = (
             f"Missing mandatory first Nox session posarg: "
             f"{run_type_arg[run_type]}"
         )
         raise ValueError(message)
+    first_arg = session.posargs[0]
     # Optional extra arguments to be passed down to ASV.
     asv_args = session.posargs[1:]
 

From 41fac3e6a768658e532c1fe412593c92684cbfae Mon Sep 17 00:00:00 2001
From: Martin Yeo <martin.yeo@metoffice.gov.uk>
Date: Mon, 14 Feb 2022 10:51:59 +0000
Subject: [PATCH 39/50] Benchmark GHA cope with there being no commits since
 yesterday.

---
 .github/workflows/benchmark.yml | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/.github/workflows/benchmark.yml b/.github/workflows/benchmark.yml
index 935686befb..5e3cd38b9f 100644
--- a/.github/workflows/benchmark.yml
+++ b/.github/workflows/benchmark.yml
@@ -67,7 +67,10 @@ jobs:
       - name: Run overnight benchmarks
         run: |
           first_commit=$(git log --after="$(date -d "1 day ago" +"%Y-%m-%d") 23:00:00" --pretty=format:"%h" | tail -n 1)
-          nox --session="benchmarks(overnight)" -- $first_commit
+          if [ "$first_commit" != "" ]
+          then
+            nox --session="benchmarks(overnight)" -- $first_commit
+          fi
 
       - name: Create issues for performance shifts
         env:

From 759e82a68c3b8e538e860b79ff1ad63feb5dcdcf Mon Sep 17 00:00:00 2001
From: Martin Yeo <martin.yeo@metoffice.gov.uk>
Date: Mon, 14 Feb 2022 20:38:36 +0000
Subject: [PATCH 40/50] Update to benchmarks README.

---
 benchmarks/README.md | 28 +++++++++++++++++++---------
 1 file changed, 19 insertions(+), 9 deletions(-)

diff --git a/benchmarks/README.md b/benchmarks/README.md
index 84538463bc..a7cba3191f 100644
--- a/benchmarks/README.md
+++ b/benchmarks/README.md
@@ -1,6 +1,3 @@
-[//]: # (the final pieces of this setup are still falling into place, so have
-         included several TODO's)
-
 # Iris Performance Benchmarking
 
 Iris uses an [Airspeed Velocity](https://github.com/airspeed-velocity/asv)
@@ -15,21 +12,34 @@ shifts in performance being flagged in a new GitHub issue.
 ## Running benchmarks
 
 `asv ...` commands must be run from this directory. You will need to have ASV
-installed, as well as Nox (see 
+installed, as well as Nox (see
 [Benchmark environments](#benchmark-environments)).
 
 [Iris' noxfile](../noxfile.py) includes a `benchmarks` session that provides
-conveniences for setting up, and even replicating the automated overnight run
-locally. See the session docstring for detail.
+conveniences for setting up before benchmarking, and can also replicate the
+automated overnight run locally. See the session docstring for detail.
 
-[//]: # (TODO: ### Environment variables section)
+### Environment variables
 
-## Writing benchmarks
+* ``DATA_GEN_PYTHON`` - required - path to a Python executable that can be
+used to generate benchmark test objects/files; see
+[Data generation](#data-generation). The Nox session sets this automatically,
+but will defer to any value already set in the shell.
+* ``BENCHMARK_DATA`` - optional - path to a directory where test files used by
+the benchmarks are saved and loaded. Defaults to ``<root>/benchmarks/.data/``
+if not set.
 
-[//]: # (TODO: ### Data generation section)
+## Writing benchmarks
 
 [See the ASV docs](https://asv.readthedocs.io/) for full detail.
 
+### Data generation
+**Important:** be sure not to use the benchmarking environment to generate any
+test objects/files, as this environment changes with each commit being
+benchmarked, creating inconsistent benchmark 'conditions'. The
+[generate_data](./benchmarks/generate_data/__init__.py) module offers a
+solution; read more detail there.
+
 ### ASV re-run behaviour
 
 Note that ASV re-runs a benchmark multiple times between its `setup()` routine.

From 339ce63748db8946802131173ae44383b17ff646 Mon Sep 17 00:00:00 2001
From: Martin Yeo <martin.yeo@metoffice.gov.uk>
Date: Mon, 14 Feb 2022 20:46:57 +0000
Subject: [PATCH 41/50] Minor noxfile docstring correction.

---
 noxfile.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/noxfile.py b/noxfile.py
index 379c28b1bd..3daedecc56 100755
--- a/noxfile.py
+++ b/noxfile.py
@@ -317,7 +317,7 @@ def benchmarks(
         * ``overnight``: benchmarks all commits between the input **first
           commit** to ``HEAD``, comparing each to its parent for performance
           shifts. If a commit causes shifts, the output is saved to a file:
-          ``performance-shifts/<commit-sha>``. Designed for checking the
+          ``.asv/performance-shifts/<commit-sha>``. Designed for checking the
           previous 24 hours' commits, typically in a scheduled script.
         * ``branch``: Performs the same operations as ``overnight``, but always
           on two commits only - ``HEAD``, and ``HEAD``'s merge-base with the

From 74b5de55ec2854fe4352866e9ca000d5a0d8bf39 Mon Sep 17 00:00:00 2001
From: Martin Yeo <martin.yeo@metoffice.gov.uk>
Date: Mon, 14 Feb 2022 20:55:40 +0000
Subject: [PATCH 42/50] Remove need for Nox benchmarks session to use Conda
 venv.

---
 noxfile.py | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/noxfile.py b/noxfile.py
index 3daedecc56..07b737f832 100755
--- a/noxfile.py
+++ b/noxfile.py
@@ -291,7 +291,7 @@ def linkcheck(session: nox.sessions.Session):
     )
 
 
-@nox.session(python=PY_VER, venv_backend="conda")
+@nox.session
 @nox.parametrize(
     "run_type",
     ["overnight", "branch", "custom"],
@@ -358,12 +358,12 @@ def benchmarks(
             "nox",
             "--session=tests",
             "--install-only",
-            f"--python={session.python}",
+            f"--python={_PY_VERSION_LATEST}",
         )
         # Find the environment built above, set it to be the data generation
         #  environment.
         data_gen_python = next(
-            Path(".nox").rglob(f"tests*/bin/python{session.python}")
+            Path(".nox").rglob(f"tests*/bin/python{_PY_VERSION_LATEST}")
         ).resolve()
         session.env[data_gen_var] = data_gen_python
 

From d0fce157b1c974a5de0dfeffb73cd716c6a00f17 Mon Sep 17 00:00:00 2001
From: Martin Yeo <martin.yeo@metoffice.gov.uk>
Date: Tue, 15 Feb 2022 16:22:41 +0000
Subject: [PATCH 43/50] Benchmark GHA get the FINAL PR from the commit string.

---
 .github/workflows/benchmark.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/benchmark.yml b/.github/workflows/benchmark.yml
index 69579d60bf..275dd98a2d 100644
--- a/.github/workflows/benchmark.yml
+++ b/.github/workflows/benchmark.yml
@@ -79,7 +79,7 @@ jobs:
             cd benchmarks/.asv/performance-shifts
             for commit_file in *
             do
-              pr_number=$(git log "$commit_file"^! --oneline | grep -o "#[0-9]*" | cut -c 2-)
+              pr_number=$(git log "$commit_file"^! --oneline | grep -o "#[0-9]*" | tail -1 | cut -c 2-)
               assignee=$(gh pr view $pr_number --json author -q '.["author"]["login"]' --repo $GITHUB_REPOSITORY)
               title="Performance Shift(s): \`$commit_file\`"
               body="

From a017b830c4432ff5d1635804f858bf25ea63ecdd Mon Sep 17 00:00:00 2001
From: Martin Yeo <martin.yeo@metoffice.gov.uk>
Date: Wed, 16 Feb 2022 11:24:27 +0000
Subject: [PATCH 44/50] ASV show-stderr in Nox benchmark session.

---
 noxfile.py | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/noxfile.py b/noxfile.py
index 07b737f832..07ef356079 100755
--- a/noxfile.py
+++ b/noxfile.py
@@ -435,9 +435,7 @@ def asv_compare(*commits):
                         shifts_file.write(shifts)
 
     # Common ASV arguments used for both `overnight` and `bench` run_types.
-    asv_harness = (
-        "asv run {posargs} --attribute rounds=4 --interleave-rounds --strict"
-    )
+    asv_harness = "asv run {posargs} --attribute rounds=4 --interleave-rounds --strict --show-stderr"
 
     if run_type == "overnight":
         first_commit = first_arg

From 0a3fb738c454636d1cea3c54c0a60584bb958032 Mon Sep 17 00:00:00 2001
From: Martin Yeo <martin.yeo@metoffice.gov.uk>
Date: Wed, 16 Feb 2022 11:24:58 +0000
Subject: [PATCH 45/50] String quote benchmark GHA CRON.

---
 .github/workflows/benchmark.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/benchmark.yml b/.github/workflows/benchmark.yml
index 275dd98a2d..2cd5d539f9 100644
--- a/.github/workflows/benchmark.yml
+++ b/.github/workflows/benchmark.yml
@@ -5,7 +5,7 @@ name: benchmark-check
 on:
   schedule:
     # Runs every day at 23:00.
-    - cron: 0 23 * * *
+    - cron: "0 23 * * *"
 
 jobs:
   benchmark:

From 08ec07ffef883cf0f5840a92438ce9a693662672 Mon Sep 17 00:00:00 2001
From: Martin Yeo <martin.yeo@metoffice.gov.uk>
Date: Wed, 16 Feb 2022 16:55:16 +0000
Subject: [PATCH 46/50] Benchmark GHA more sensible title comment.

---
 .github/workflows/benchmark.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/benchmark.yml b/.github/workflows/benchmark.yml
index 2cd5d539f9..d4c01af48a 100644
--- a/.github/workflows/benchmark.yml
+++ b/.github/workflows/benchmark.yml
@@ -1,4 +1,4 @@
-# This is a basic workflow to help you get started with Actions
+# Use ASV to check for performance regressions in the last 24 hours' commits.
 
 name: benchmark-check
 

From b1fd50560a9eded3438aca4dce266bd6acc19dd2 Mon Sep 17 00:00:00 2001
From: Martin Yeo <martin.yeo@metoffice.gov.uk>
Date: Wed, 16 Feb 2022 16:57:33 +0000
Subject: [PATCH 47/50] Benchmark Nox asv_command_type > asv_subcommand.

---
 noxfile.py | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/noxfile.py b/noxfile.py
index 07ef356079..2662aec561 100755
--- a/noxfile.py
+++ b/noxfile.py
@@ -327,7 +327,7 @@ def benchmarks(
           merged.
           **For maximum accuracy, avoid using the machine that is running this
           session. Run time could be >1 hour for the full benchmark suite.**
-        * ``custom``: run ASV with the input **ASV command type**, without any
+        * ``custom``: run ASV with the input **ASV sub-command**, without any
           preset arguments - must all be supplied by the user. So just like
           running ASV manually, with the convenience of re-using the session's
           scripted setup steps.
@@ -395,7 +395,7 @@ def benchmarks(
     run_type_arg = {
         "overnight": "first commit",
         "branch": "base branch",
-        "custom": "ASV command type",
+        "custom": "ASV sub-command",
     }
     if run_type not in run_type_arg.keys():
         message = f"Unsupported run-type: {run_type}"
@@ -468,5 +468,5 @@ def asv_compare(*commits):
         asv_compare(merge_base, "HEAD")
 
     else:
-        asv_command_type = first_arg
-        session.run("asv", asv_command_type, *asv_args)
+        asv_subcommand = first_arg
+        session.run("asv", asv_subcommand, *asv_args)

From 6a4fcf94fb2da70dbbb2d82c0afbf816ff26d062 Mon Sep 17 00:00:00 2001
From: Martin Yeo <martin.yeo@metoffice.gov.uk>
Date: Wed, 16 Feb 2022 16:58:48 +0000
Subject: [PATCH 48/50] Benchmark Nox check correct run_type.

---
 noxfile.py | 1 +
 1 file changed, 1 insertion(+)

diff --git a/noxfile.py b/noxfile.py
index 2662aec561..ae689d3acd 100755
--- a/noxfile.py
+++ b/noxfile.py
@@ -469,4 +469,5 @@ def asv_compare(*commits):
 
     else:
         asv_subcommand = first_arg
+        assert run_type == "custom"
         session.run("asv", asv_subcommand, *asv_args)

From f69ba641d383447f3bc70d5c208786029c5a23eb Mon Sep 17 00:00:00 2001
From: Martin Yeo <martin.yeo@metoffice.gov.uk>
Date: Wed, 16 Feb 2022 17:01:48 +0000
Subject: [PATCH 49/50] Benchmark Nox clarify shifts_dir.

---
 noxfile.py | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/noxfile.py b/noxfile.py
index ae689d3acd..e4d91c6bab 100755
--- a/noxfile.py
+++ b/noxfile.py
@@ -429,6 +429,8 @@ def asv_compare(*commits):
                 )
                 if shifts:
                     # Write the shifts report to a file.
+                    # Dir is used by .github/workflows/benchmarks.yml,
+                    #  but not cached - intended to be discarded after run.
                     shifts_dir.mkdir(exist_ok=True, parents=True)
                     shifts_path = shifts_dir / after
                     with shifts_path.open("w") as shifts_file:

From 9808a9b5aeaa668d3b6f7dfd87831d41405fc064 Mon Sep 17 00:00:00 2001
From: Martin Yeo <martin.yeo@metoffice.gov.uk>
Date: Wed, 16 Feb 2022 17:04:39 +0000
Subject: [PATCH 50/50] Benchmark README clarify BENCHMARK_DATA.

---
 benchmarks/README.md | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/benchmarks/README.md b/benchmarks/README.md
index a7cba3191f..baa1afe700 100644
--- a/benchmarks/README.md
+++ b/benchmarks/README.md
@@ -25,9 +25,9 @@ automated overnight run locally. See the session docstring for detail.
 used to generate benchmark test objects/files; see
 [Data generation](#data-generation). The Nox session sets this automatically,
 but will defer to any value already set in the shell.
-* ``BENCHMARK_DATA`` - optional - path to a directory where test files used by
-the benchmarks are saved and loaded. Defaults to ``<root>/benchmarks/.data/``
-if not set.
+* ``BENCHMARK_DATA`` - optional - path to a directory for benchmark synthetic
+test data, which the benchmark scripts will create if it doesn't already
+exist. Defaults to ``<root>/benchmarks/.data/`` if not set.
 
 ## Writing benchmarks