Fix timer handle churn in websocket heartbeat

[bdraco]

What do these changes do?

Each message would cancel and reset the timer handler which meant asyncio would have to rebuild the whole schedule heap frequently because so many timer handlers were being created and than cancelled.

When asyncio timer handle cancels reach the threadhold the whole heap has to be rebuilt
https://github.com/python/cpython/blob/1422500d020bd199b26357fc387f8b79b82226cd/Lib/asyncio/base_events.py#L1968 which is extremely inefficent.

To solve this, when a timer handle is already running, instead of cancelling it, we let it fire and reschedule if heartbeat would be sent to early.

The websocket ping/pong code was missing some coverage in this area so there are some new tests as well.

Are there changes in behavior for the user?

no

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

no

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 97.87%. Comparing base (b2691f2) to head (f9c6027).

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #8608      +/-   ##
==========================================
- Coverage   97.90%   97.87%   -0.04%     
==========================================
  Files         107      107              
  Lines       33515    33669     +154     
  Branches     3941     3952      +11     
==========================================
+ Hits        32813    32952     +139     
- Misses        518      533      +15     
  Partials      184      184              

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[bdraco]

We don't have any tests for when the heartbeat would get rescheduled. Need to write some.

[bdraco]

95.2% reduction in websocket client timer handler churn. That's even with the downstream libs that already have their own ping/pong implementation.

I'm happy with this. I'll let it bake overnight and than write some tests tomorrow if I don't have any more fires from my day job to put out.

[bdraco]

95.1% reduction on the other instance I tested this on

[Dreamsorcerer]

Looks good to me. I'm about to update these test files with type checking though, so would be great if you can update after those changes.

[bdraco]

Thanks!

[patchback]

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

❌ Failed to cleanly apply c4acabc on top of patchback/backports/3.10/c4acabc836ab969e95199aa976e85c01df720a27/pr-8608

Backporting merged PR #8608 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/c4acabc836ab969e95199aa976e85c01df720a27/pr-8608 upstream/3.10

4. Now, cherry-pick PR Fix timer handle churn in websocket heartbeat #8608 contents into that branch:

   $ git cherry-pick -x c4acabc836ab969e95199aa976e85c01df720a27

   If it'll yell at you with something like fatal: Commit c4acabc836ab969e95199aa976e85c01df720a27 is a merge but no -m option was given., add -m 1 as follows instead:

   $ git cherry-pick -m1 -x c4acabc836ab969e95199aa976e85c01df720a27

5. At this point, you'll probably encounter some merge conflicts. You must
   resolve them in to preserve the patch from PR Fix timer handle churn in websocket heartbeat #8608 as close to the
   original as possible.
6. Push this branch to your fork on GitHub:

   $ git push origin patchback/backports/3.10/c4acabc836ab969e95199aa976e85c01df720a27/pr-8608

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.

[patchback]

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

❌ Failed to cleanly apply c4acabc on top of patchback/backports/3.11/c4acabc836ab969e95199aa976e85c01df720a27/pr-8608

Backporting merged PR #8608 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/c4acabc836ab969e95199aa976e85c01df720a27/pr-8608 upstream/3.11

4. Now, cherry-pick PR Fix timer handle churn in websocket heartbeat #8608 contents into that branch:

   $ git cherry-pick -x c4acabc836ab969e95199aa976e85c01df720a27

   If it'll yell at you with something like fatal: Commit c4acabc836ab969e95199aa976e85c01df720a27 is a merge but no -m option was given., add -m 1 as follows instead:

   $ git cherry-pick -m1 -x c4acabc836ab969e95199aa976e85c01df720a27

5. At this point, you'll probably encounter some merge conflicts. You must
   resolve them in to preserve the patch from PR Fix timer handle churn in websocket heartbeat #8608 as close to the
   original as possible.
6. Push this branch to your fork on GitHub:

   $ git push origin patchback/backports/3.11/c4acabc836ab969e95199aa976e85c01df720a27/pr-8608

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.