Avoid starting connection timeout when a connection is already available

[bdraco]

What do these changes do?

Since connection re-use is common, we can avoid starting the ceil_timeout when we have a connection immediately available. Previously when a connection is already available for reuse, ceil_timeout had to create a TimerHandle, schedule it on the event loop, and then immediately cancel it, leaving the loop to have to remove it from the heap. See #8608 (comment) and #8613 for more history on the overhead of this set of operations.

If the server supports keep-alive, the hit rate on avoiding the timeout is over 80% in testing. 31b9637

closes #9598

Are there changes in behavior for the user?

If BaseConnector.connect was replaced with a custom connect function, the timeout must now be handled in this function. The only abstract method the docs specify to be overwritten is _create_connection. While it seems extremely unlikely that someone would write out a custom connect function since it would likely break all the protected calls back into the connector from Connection, I think this change is likely safe to backport. To be on the safe side I only tagged it for 3.11 (tested in #9601) in case someone is doing that. This was originally planned not to backport to 3.10, but its needed to fix #9670

aiohttp/connector.py:            self._connector._release(self._key, self._protocol, should_close=True)
aiohttp/connector.py:            self._connector._release(self._key, self._protocol, should_close=True)
aiohttp/connector.py:            self._connector._release(

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

no

Benchmarks
See script in #9598

aiohttp 3.10.0, yarl 1.9.5

aiohttp 3.11.0b0 yarl 1.17.0

aiohttp 3.11.0b0+ this change yarl 1.17.0

aiohttp 3.11.0b0+ this change yarl 1.17.1

[codspeed-hq]

CodSpeed Performance Report

Merging #9600 will not alter performance

_{Comparing connect_no_timeout_no_connect (c7ed98c) with master (7d0f980)}

Summary

✅ 7 untouched benchmarks

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 98.63%. Comparing base (7d0f980) to head (c7ed98c).
Report is 21 commits behind head on master.

✅ All tests successful. No failed tests found.

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #9600   +/-   ##
=======================================
  Coverage   98.62%   98.63%           
=======================================
  Files         113      113           
  Lines       35299    35306    +7     
  Branches     4189     4191    +2     
=======================================
+ Hits        34814    34823    +9     
+ Misses        325      323    -2     
  Partials      160      160           

Flag	Coverage Δ
CI-GHA	98.51% <100.00%> (+<0.01%)	⬆️
OS-Linux	98.19% <100.00%> (+<0.01%)	⬆️
OS-Windows	96.08% <100.00%> (+<0.01%)	⬆️
OS-macOS	97.40% <100.00%> (+<0.01%)	⬆️
Py-3.10.11	97.25% <97.43%> (+<0.01%)	⬆️
Py-3.10.15	97.66% <97.43%> (+<0.01%)	⬆️
Py-3.11.10	97.73% <97.43%> (-0.01%)	⬇️
Py-3.11.9	97.33% <97.43%> (+<0.01%)	⬆️
Py-3.12.7	98.22% <100.00%> (+<0.01%)	⬆️
Py-3.13.0	98.20% <100.00%> (+<0.01%)	⬆️
Py-3.9.13	97.17% <100.00%> (+<0.01%)	⬆️
Py-3.9.20	97.57% <100.00%> (+<0.01%)	⬆️
Py-pypy7.3.16	97.19% <100.00%> (+<0.01%)	⬆️
VM-macos	97.40% <100.00%> (+<0.01%)	⬆️
VM-ubuntu	98.19% <100.00%> (+<0.01%)	⬆️
VM-windows	96.08% <100.00%> (+<0.01%)	⬆️

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[patchback]

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

❌ Failed to cleanly apply e6187f6 on top of patchback/backports/3.11/e6187f6808d647243d8cee115ec24c3eb1421183/pr-9600

Backporting merged PR #9600 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/3.11/e6187f6808d647243d8cee115ec24c3eb1421183/pr-9600 upstream/3.11

4. Now, cherry-pick PR Avoid starting connection timeout when a connection is already available #9600 contents into that branch:

   $ git cherry-pick -x e6187f6808d647243d8cee115ec24c3eb1421183

   If it'll yell at you with something like fatal: Commit e6187f6808d647243d8cee115ec24c3eb1421183 is a merge but no -m option was given., add -m 1 as follows instead:

   $ git cherry-pick -m1 -x e6187f6808d647243d8cee115ec24c3eb1421183

5. At this point, you'll probably encounter some merge conflicts. You must
   resolve them in to preserve the patch from PR Avoid starting connection timeout when a connection is already available #9600 as close to the
   original as possible.
6. Push this branch to your fork on GitHub:

   $ git push origin patchback/backports/3.11/e6187f6808d647243d8cee115ec24c3eb1421183/pr-9600

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://github.com/sanitizers/patchback-github-app.

[bdraco]

Tagging for backport to 3.10 as well since we need it to fix #9670 since a deadlock takes precedence of the potential risks from this PR

[patchback]

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

❌ Failed to cleanly apply e6187f6 on top of patchback/backports/3.10/e6187f6808d647243d8cee115ec24c3eb1421183/pr-9600

Backporting merged PR #9600 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/e6187f6808d647243d8cee115ec24c3eb1421183/pr-9600 upstream/3.10

4. Now, cherry-pick PR Avoid starting connection timeout when a connection is already available #9600 contents into that branch:

   $ git cherry-pick -x e6187f6808d647243d8cee115ec24c3eb1421183

   If it'll yell at you with something like fatal: Commit e6187f6808d647243d8cee115ec24c3eb1421183 is a merge but no -m option was given., add -m 1 as follows instead:

   $ git cherry-pick -m1 -x e6187f6808d647243d8cee115ec24c3eb1421183

5. At this point, you'll probably encounter some merge conflicts. You must
   resolve them in to preserve the patch from PR Avoid starting connection timeout when a connection is already available #9600 as close to the
   original as possible.
6. Push this branch to your fork on GitHub:

   $ git push origin patchback/backports/3.10/e6187f6808d647243d8cee115ec24c3eb1421183/pr-9600

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://github.com/sanitizers/patchback-github-app.