Improve performance of WebSockets when there is no timeout

[bdraco]

What do these changes do?

The common case for WebSockets is to call receive without a timeout, or use the WebSocketResponse as an async iterator. The read was always wrapped with an async timeout even if the timeout was not used which accounted for as much as 50% of the run time each loop. If there is no timeout, avoid wrapping the read call in the context manager which creates a new Timeout() object each time.

Are there changes in behavior for the user?

Performance improvement

related reading https://www.researchgate.net/publication/348993267_An_Analysis_of_the_Performance_of_Websockets_in_Various_Programming_Languages_and_Libraries

Is it a substantial burden for the maintainers to support this?

no

before

after

[bdraco]

This should significantly help aiounifi, aioshelly, and uiprotect which they are have quite a bit of incoming websocket traffic.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 97.97%. Comparing base (6c6ecfa) to head (91775cb).

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #8660   +/-   ##
=======================================
  Coverage   97.97%   97.97%           
=======================================
  Files         107      107           
  Lines       33780    33786    +6     
  Branches     3966     3968    +2     
=======================================
+ Hits        33096    33102    +6     
  Misses        507      507           
  Partials      177      177           

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[Dreamsorcerer]

I wonder if there's a way to improve the timeout version too...

[bdraco]

I wonder if there's a way to improve the timeout version too...

Nothing obvious stands out in https:/python/cpython/blob/2f5c3b09e45798a18d60841d04a165fb062be666/Lib/asyncio/timeouts.py#L85 but I also haven't stared at it long enough.

[bdraco]

Thanks!

[patchback]

Backport to 3.10: 💔 cherry-picking failed — conflicts found

❌ Failed to cleanly apply 14d5295 on top of patchback/backports/3.10/14d52957290e88748f37ed396c68a23d13a7ecda/pr-8660

Backporting merged PR #8660 into master

1. Ensure you have a local repo clone of your fork. Unless you cloned it
   from the upstream, this would be your origin remote.
2. Make sure you have an upstream repo added as a remote too. In these
   instructions you'll refer to it by the name upstream. If you don't
   have it, here's how you can add it:

   $ git remote add upstream https:/aio-libs/aiohttp.git

3. Ensure you have the latest copy of upstream and prepare a branch
   that will hold the backported code:

   $ git fetch upstream
   $ git checkout -b patchback/backports/3.10/14d52957290e88748f37ed396c68a23d13a7ecda/pr-8660 upstream/3.10

4. Now, cherry-pick PR Improve performance of WebSockets when there is no timeout #8660 contents into that branch:

   $ git cherry-pick -x 14d52957290e88748f37ed396c68a23d13a7ecda

   If it'll yell at you with something like fatal: Commit 14d52957290e88748f37ed396c68a23d13a7ecda is a merge but no -m option was given., add -m 1 as follows instead:

   $ git cherry-pick -m1 -x 14d52957290e88748f37ed396c68a23d13a7ecda

5. At this point, you'll probably encounter some merge conflicts. You must
   resolve them in to preserve the patch from PR Improve performance of WebSockets when there is no timeout #8660 as close to the
   original as possible.
6. Push this branch to your fork on GitHub:

   $ git push origin patchback/backports/3.10/14d52957290e88748f37ed396c68a23d13a7ecda/pr-8660

7. Create a PR, ensure that the CI is green. If it's not — update it so that
   the tests and any other checks pass. This is it!
   Now relax and wait for the maintainers to process your pull request
   when they have some cycles to do reviews. Don't worry — they'll tell you if
   any improvements are necessary when the time comes!

🤖 @patchback
I'm built with octomachinery and
my source is open — https:/sanitizers/patchback-github-app.

[patchback]

Backport to 3.11: 💔 cherry-picking failed — conflicts found

❌ Failed to cleanly apply 14d5295 on top of patchback/backports/3.11/14d52957290e88748f37ed396c68a23d13a7ecda/pr-8660

Backporting merged PR #8660 into master

1. Ensure you have a local repo clone of your fork. Unless you cloned it
   from the upstream, this would be your origin remote.
2. Make sure you have an upstream repo added as a remote too. In these
   instructions you'll refer to it by the name upstream. If you don't
   have it, here's how you can add it:

   $ git remote add upstream https:/aio-libs/aiohttp.git

3. Ensure you have the latest copy of upstream and prepare a branch
   that will hold the backported code:

   $ git fetch upstream
   $ git checkout -b patchback/backports/3.11/14d52957290e88748f37ed396c68a23d13a7ecda/pr-8660 upstream/3.11

4. Now, cherry-pick PR Improve performance of WebSockets when there is no timeout #8660 contents into that branch:

   $ git cherry-pick -x 14d52957290e88748f37ed396c68a23d13a7ecda

   If it'll yell at you with something like fatal: Commit 14d52957290e88748f37ed396c68a23d13a7ecda is a merge but no -m option was given., add -m 1 as follows instead:

   $ git cherry-pick -m1 -x 14d52957290e88748f37ed396c68a23d13a7ecda

5. At this point, you'll probably encounter some merge conflicts. You must
   resolve them in to preserve the patch from PR Improve performance of WebSockets when there is no timeout #8660 as close to the
   original as possible.
6. Push this branch to your fork on GitHub:

   $ git push origin patchback/backports/3.11/14d52957290e88748f37ed396c68a23d13a7ecda/pr-8660

7. Create a PR, ensure that the CI is green. If it's not — update it so that
   the tests and any other checks pass. This is it!
   Now relax and wait for the maintainers to process your pull request
   when they have some cycles to do reviews. Don't worry — they'll tell you if
   any improvements are necessary when the time comes!

🤖 @patchback
I'm built with octomachinery and
my source is open — https:/sanitizers/patchback-github-app.

[bdraco]

I wonder if there's a way to improve the timeout version too...

Found a way to make it faster python/cpython#122882