Limit memory benchmark result to 5Mb minimum

benchmarks/benchmarks/__init__.py

@@ -4,7 +4,6 @@
 # See COPYING and COPYING.LESSER in the root of the repository for full
 # licensing details.
 """Common code for benchmarks."""
-from functools import wraps
 from os import environ
 import resource
 
@@ -54,8 +53,20 @@ class TrackAddedMemoryAllocation:
             other_call()
         result = mb.addedmem_mb()
 
+    Attributes
+    ----------
+    RESULT_MINIMUM_MB : float
+        The smallest result that should ever be returned, in Mb. Results
+        fluctuate from run to run (usually within 1Mb) so if a result is
+        sufficiently small this noise will produce a before-after ratio over
+        AVD's detection threshold and be treated as 'signal'. Results
+        smaller than this value will therefore be returned as equal to this
+        value, ensuring fractionally small noise / no noise at all.
+
     """
 
+    RESULT_MINIMUM_MB = 5.0
+
     @staticmethod
     def process_resident_memory_mb():
         return resource.getrusage(resource.RUSAGE_SELF).ru_maxrss / 1024.0
@@ -69,48 +80,32 @@ def __exit__(self, *_):
 
     def addedmem_mb(self):
         """Return measured memory growth, in Mb."""
-        return self.mb_after - self.mb_before
+        result = self.mb_after - self.mb_before
+        # Small results are too vulnerable to noise being interpreted as signal.
+        result = max(self.RESULT_MINIMUM_MB, result)
+        return result
 
     @staticmethod
-    def decorator(changed_params: list = None):
+    def decorator(decorated_func):
         """
         Decorates this benchmark to track growth in resident memory during execution.
 
         Intended for use on ASV ``track_`` benchmarks. Applies the
         :class:`TrackAddedMemoryAllocation` context manager to the benchmark
-        code, sets the benchmark ``unit`` attribute to ``Mb``. Optionally
-        replaces the benchmark ``params`` attribute with ``changed_params`` -
-        useful to avoid testing very small memory volumes, where the results
-        are vulnerable to noise.
-
-        Parameters
-        ----------
-        changed_params : list
-            Replace the benchmark's ``params`` attribute with this list.
+        code, sets the benchmark ``unit`` attribute to ``Mb``.
 
         """
-        if changed_params:
-            # Must make a copy for re-use safety!
-            _changed_params = list(changed_params)
-        else:
-            _changed_params = None
-
-        def _inner_decorator(decorated_func):
-            @wraps(decorated_func)
-            def _inner_func(*args, **kwargs):
-                assert decorated_func.__name__[:6] == "track_"
-                # Run the decorated benchmark within the added memory context manager.
-                with TrackAddedMemoryAllocation() as mb:
-                    decorated_func(*args, **kwargs)
-                return mb.addedmem_mb()
-
-            if _changed_params:
-                # Replace the params if replacement provided.
-                _inner_func.params = _changed_params
-            _inner_func.unit = "Mb"
-            return _inner_func
-
-        return _inner_decorator
+
+        def _wrapper(*args, **kwargs):
+            assert decorated_func.__name__[:6] == "track_"
+            # Run the decorated benchmark within the added memory context
+            # manager.
+            with TrackAddedMemoryAllocation() as mb:
+                decorated_func(*args, **kwargs)
+            return mb.addedmem_mb()
+
+        decorated_func.unit = "Mb"
+        return _wrapper
 
 
 def on_demand_benchmark(benchmark_object):

benchmarks/benchmarks/cperf/save.py

@@ -42,6 +42,6 @@ def _save_data(self, cube):
     def time_save_data_netcdf(self, data_type):
         self._save_data(self.cube)
 
-    @TrackAddedMemoryAllocation.decorator()
+    @TrackAddedMemoryAllocation.decorator
     def track_addedmem_save_data_netcdf(self, data_type):
         self._save_data(self.cube)

benchmarks/benchmarks/experimental/ugrid/regions_combine.py

@@ -33,8 +33,6 @@ class MixinCombineRegions:
     # operations on cubesphere-like test data.
     params = [4, 500]
     param_names = ["cubesphere-N"]
-    # For use on 'track_addedmem_..' type benchmarks - result is too noisy.
-    no_small_params = params[1:]
 
     def _parametrised_cache_filename(self, n_cubesphere, content_name):
         return f"cube_C{n_cubesphere}_{content_name}.nc"
@@ -190,7 +188,7 @@ def setup(self, n_cubesphere):
     def time_create_combined_cube(self, n_cubesphere):
         self.recombine()
 
-    @TrackAddedMemoryAllocation.decorator(MixinCombineRegions.no_small_params)
+    @TrackAddedMemoryAllocation.decorator
     def track_addedmem_create_combined_cube(self, n_cubesphere):
         self.recombine()
 
@@ -203,7 +201,7 @@ class CombineRegionsComputeRealData(MixinCombineRegions):
     def time_compute_data(self, n_cubesphere):
         _ = self.recombined_cube.data
 
-    @TrackAddedMemoryAllocation.decorator(MixinCombineRegions.no_small_params)
+    @TrackAddedMemoryAllocation.decorator
     def track_addedmem_compute_data(self, n_cubesphere):
         _ = self.recombined_cube.data
 
@@ -220,7 +218,7 @@ def time_save(self, n_cubesphere):
         # Save to disk, which must compute data + stream it to file.
         save(self.recombined_cube, "tmp.nc")
 
-    @TrackAddedMemoryAllocation.decorator(MixinCombineRegions.no_small_params)
+    @TrackAddedMemoryAllocation.decorator
     def track_addedmem_save(self, n_cubesphere):
         save(self.recombined_cube, "tmp.nc")
 
@@ -248,6 +246,6 @@ def time_stream_file2file(self, n_cubesphere):
         # Save to disk, which must compute data + stream it to file.
         save(self.recombined_cube, "tmp.nc")
 
-    @TrackAddedMemoryAllocation.decorator(MixinCombineRegions.no_small_params)
+    @TrackAddedMemoryAllocation.decorator
     def track_addedmem_stream_file2file(self, n_cubesphere):
         save(self.recombined_cube, "tmp.nc")

benchmarks/benchmarks/save.py

@@ -24,8 +24,6 @@
 class NetcdfSave:
     params = [[1, 600], [False, True]]
     param_names = ["cubesphere-N", "is_unstructured"]
-    # For use on 'track_addedmem_..' type benchmarks - result is too noisy.
-    no_small_params = [[600], [True]]
 
     def setup(self, n_cubesphere, is_unstructured):
         self.cube = make_cube_like_2d_cubesphere(
@@ -50,7 +48,7 @@ def time_netcdf_save_mesh(self, n_cubesphere, is_unstructured):
         if is_unstructured:
             self._save_mesh(self.cube)
 
-    @TrackAddedMemoryAllocation.decorator(no_small_params)
+    @TrackAddedMemoryAllocation.decorator
     def track_addedmem_netcdf_save(self, n_cubesphere, is_unstructured):
         # Don't need to copy the cube here since track_ benchmarks don't
         #  do repeats between self.setup() calls.

benchmarks/benchmarks/sperf/combine_regions.py

@@ -192,7 +192,7 @@ def setup(
     def time_create_combined_cube(self, n_cubesphere):
         self.recombine()
 
-    @TrackAddedMemoryAllocation.decorator()
+    @TrackAddedMemoryAllocation.decorator
     def track_addedmem_create_combined_cube(self, n_cubesphere):
         self.recombine()
 
@@ -206,7 +206,7 @@ class ComputeRealData(Mixin):
     def time_compute_data(self, n_cubesphere):
         _ = self.recombined_cube.data
 
-    @TrackAddedMemoryAllocation.decorator()
+    @TrackAddedMemoryAllocation.decorator
     def track_addedmem_compute_data(self, n_cubesphere):
         _ = self.recombined_cube.data
 
@@ -224,7 +224,7 @@ def time_save(self, n_cubesphere):
         # Save to disk, which must compute data + stream it to file.
         self.save_recombined_cube()
 
-    @TrackAddedMemoryAllocation.decorator()
+    @TrackAddedMemoryAllocation.decorator
     def track_addedmem_save(self, n_cubesphere):
         self.save_recombined_cube()
 
@@ -252,6 +252,6 @@ def time_stream_file2file(self, n_cubesphere):
         # Save to disk, which must compute data + stream it to file.
         self.save_recombined_cube()
 
-    @TrackAddedMemoryAllocation.decorator()
+    @TrackAddedMemoryAllocation.decorator
     def track_addedmem_stream_file2file(self, n_cubesphere):
         self.save_recombined_cube()

benchmarks/benchmarks/sperf/save.py

@@ -41,7 +41,7 @@ def _save_mesh(self, cube):
     def time_save_cube(self, n_cubesphere, is_unstructured):
         self._save_cube(self.cube)
 
-    @TrackAddedMemoryAllocation.decorator()
+    @TrackAddedMemoryAllocation.decorator
     def track_addedmem_save_cube(self, n_cubesphere, is_unstructured):
         self._save_cube(self.cube)