pip hangs even at simple commands

[beruic]

After finding my old Raspberry Pi and starting to play with it, it has become apparent to me that pip hangs initially on every command. Even a simple pip -h takes 7 seconds on my Raspberry Pi.

I checked this on my regular computer, and noticed a small delay on that one too. something that works purely locally, like pip -h or pip freeze, should be blazing fast.

[dstufft]

Does this happen if you pass --disable-pip-version-check as an option?

[beruic]

I finally got to try it out. Still takes 7 seconds to do a pip freeze with or without the option.

[xavfernandez]

From what I rememeber when I had looked at it, one major source of slowness came from the import of pkg_resources (which happens whatever you are doing in pip), because it checks all the paths for installed python modules.

From a small sample of calls:

• fastest time pip took 311 ms on my machine.
• fastest time python -c "import pkg_resources" took 165 ms

We could maybe try to only import pkg_resources when necessary but I don't feel this is a major issue.

[beruic]

I agree this is not major. Just annoying when you work with slow hardware, like the Raspberry Pi :)
However it seems to be only really bad on older Pis with a single core.

[tiagoboldt]

Lack of performance on the Raspberry Pi doesn't seem to be a pip issue, but a python's one. Most python applications that load multiple libraries take a huge time to start. I don't believe there will be something to do on pip's side.

[dstufft]

Closing this, this seems to be an issue related to the performance of the Raspberry Pi and there's not much pip can do about it.

[DMW007]

I'd fallen into this issue since I started using docker-compose with pip, as recommended in the Docker docs. Even simple commands like --version take seconds to complete:

pi@pi3:~ $ time docker-compose --version
docker-compose version 1.16.1, build 6d1ac219

real    0m6,700s
user    0m6,380s
sys     0m0,260s

It seems caused by pip, since both pip2 and pip3 are compareable slow:

pi@pi3:~ $ time pip2 --version
pip 9.0.1 from /usr/lib/python2.7/dist-packages (python 2.7)

real    0m5,446s
user    0m5,260s
sys     0m0,130s

pi@pi3:~ $ time pip3 --version
pip 9.0.1 from /usr/lib/python3/dist-packages (python 3.5)

real    0m8,436s
user    0m8,230s
sys     0m0,150s

I couldn't belive that this is caused by the hardware of the Raspberry Pi. I tested this on both Raspberry 2 and 3, both are slow on docker-compose/pip. Altough the Pi3 is faster than the 2. Only Pip seems affected, cause other tools like docker itself are pretty fast:

pi@pi3:~ $ time docker --version
Docker version 17.09.0-ce, build afdb6d4

real    0m0,109s
user    0m0,060s
sys     0m0,040s

[pradyunsg]

@DMWOO7 That is indeed something we're looking into improving in the future -- there's #4768 for that.