Avoid creating a future on every websocket receive

[bdraco]

What do these changes do?

We should only create a future on close if we wait for the receive to finish. Instead of making the future every time receive is called, we should only create it when we are closing and let the close call await it only if receive is waiting. Since close is called far less frequently than receive in most cases, this is far more efficient.

There was also a nice decrease in set_result calls and a reduction of ~1000 future creations per minute on an HA install with 14 WebSocket connections open. Users with many WebSocket connections will see a much more substantial drop. WebSockets should scale better with this change, especially if they are highly active.

The future was added in ae38c4a , and the test_concurrent_close tests still pass with only creating the future on close

Are there changes in behavior for the user?

no

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

no

Related issue number

Checklist

• I think the code is well written
• Unit tests for the changes exist
• Documentation reflects the changes
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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 97.61%. Comparing base (c086795) to head (fa9b820).
Report is 918 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #8498   +/-   ##
=======================================
  Coverage   97.61%   97.61%           
=======================================
  Files         107      107           
  Lines       33104    33159   +55     
  Branches     3892     3895    +3     
=======================================
+ Hits        32314    32369   +55     
  Misses        571      571           
  Partials      219      219           

Flag	Coverage Δ
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Py-3.9.13	96.99% <100.00%> (+<0.01%)	⬆️
Py-3.9.19	96.95% <100.00%> (+<0.01%)	⬆️
Py-pypy7.3.16	96.52% <100.00%> (+<0.01%)	⬆️
VM-macos	96.86% <100.00%> (+<0.01%)	⬆️
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[bdraco]

I think this needs a test where concurrent tasks close the connection at the same time before receive is done in another task

[bdraco]

thanks

[patchback]

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

❌ Failed to cleanly apply 7bf6ee1 on top of patchback/backports/3.10/7bf6ee1719e8b98d4aa9c7578ed016123ee888d9/pr-8498

Backporting merged PR #8498 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://github.com/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/3.10/7bf6ee1719e8b98d4aa9c7578ed016123ee888d9/pr-8498 upstream/3.10

4. Now, cherry-pick PR Avoid creating a future on every websocket receive #8498 contents into that branch:

   $ git cherry-pick -x 7bf6ee1719e8b98d4aa9c7578ed016123ee888d9

   If it'll yell at you with something like fatal: Commit 7bf6ee1719e8b98d4aa9c7578ed016123ee888d9 is a merge but no -m option was given., add -m 1 as follows instead:

   $ git cherry-pick -m1 -x 7bf6ee1719e8b98d4aa9c7578ed016123ee888d9

5. At this point, you'll probably encounter some merge conflicts. You must
   resolve them in to preserve the patch from PR Avoid creating a future on every websocket receive #8498 as close to the
   original as possible.
6. Push this branch to your fork on GitHub:

   $ git push origin patchback/backports/3.10/7bf6ee1719e8b98d4aa9c7578ed016123ee888d9/pr-8498

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!

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