This PR implements a work-stealing thread pool for use inside
EventEngine implementations. Because of historical risks here, I've
guarded the new implementation behind an experiment flag:
`GRPC_EXPERIMENTS=work_stealing`. Current default behavior is the
original thread pool implementation.
Benchmarks look very promising:
```
bazel test \
--test_timeout=300 \
--config=opt -c opt \
--test_output=streamed \
--test_arg='--benchmark_format=csv' \
--test_arg='--benchmark_min_time=0.15' \
--test_arg='--benchmark_filter=_FanOut' \
--test_arg='--benchmark_repetitions=15' \
--test_arg='--benchmark_report_aggregates_only=true' \
test/cpp/microbenchmarks:bm_thread_pool
```
2023-05-04: `bm_thread_pool` benchmark results on my local machine (64
core ThreadRipper PRO 3995WX, 256GB memory), comparing this PR to
master:
2023-05-04: `bm_thread_pool` benchmark results in the Linux RBE
environment (unsure of machine configuration, likely small), comparing
this PR to master.
---------
Co-authored-by: drfloob <drfloob@users.noreply.github.com>
Discovered via `bazel test
--test_env=GRPC_EXPERIMENTS=event_engine_client
//test/core/iomgr:endpoint_pair_test`. CI experiments can be enabled
generally on Windows once a few fixes and improvements are completed.
Relands #32385 (reverted in #32419) with fixes.
The Windows build is clean on a test cherrypick: cl/511291828
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---------
Co-authored-by: drfloob <drfloob@users.noreply.github.com>
A handful of problems were identified while writing the
WindowsEventEngine Listener. To make the listener review easier, these
fixes can be landed separately.
This is built upon https://github.com/grpc/grpc/pull/32376
Problems that are fixed in this PR:
* `OnConnectCompleted` held a Mutex while calling the user callback,
which can deadlock.
* The WinSocket and some associated data needs to remain alive after the
Endpoint destroyed, since Windows IOCP still needs to use some of that
data. Endpoint destruction and socket shutdown are now decoupled, with
the socket managed by a shared_ptr.
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---------
Co-authored-by: drfloob <drfloob@users.noreply.github.com>
We have many tests that create 100 threads or more, and mounting evidence that
this is harmful to our CI environment.
When the original code for many of these tests was written we ran our tests
under run_tests, which had explicit handling for tracking the number of threads
each test needed and making sure that we weren't over subscribing the test
runner. Bazel has no such facility (and the facility in run_tests has since
been removed) and so we need to adjust.
This PR adjusts down a single test and is part of a series so that we can
review and roll back easily if required.
This is a partial fork of the windows iomgr code - specifically the IOCP and Socket pieces - with some improved architecture and encapsulation. And the start of a WindowsEventEngine.
Once this code is used in a gRPC TCP context, I imagine a few issues will shake out. Also, getting sanitizers set up with MSVC will take a bit of work (see a commit referencing abseil and MSVC bugs to hack around).
I forked the IomgrEventEngine's posix poller interfaces in the hope of negotiating compatibility between the platforms, but the interfaces diverged a fair bit, and I'm doubtful we'll be able to use these "pollers" generically in the same TCP code. Reunification might not happen, and that's probably fine, we'll see how similar the TCP code looks once it's fleshed out.
I also extracted the IomgrEventEngine's timer piece into a separate component, usable by both engines.
AJ Heller
