Re: [PULL 0/1] Block patches

From: Stefan Hajnoczi <stefanha@redhat.com>
To: Richard Henderson <richard.henderson@linaro.org>
Cc: Kevin Wolf <kwolf@redhat.com>,
	Peter Maydell <peter.maydell@linaro.org>,
	qemu-devel@nongnu.org, qemu-block@nongnu.org,
	Paolo Bonzini <pbonzini@redhat.com>
Subject: Re: [PULL 0/1] Block patches
Date: Mon, 25 Oct 2021 11:10:07 +0100	[thread overview]
Message-ID: <YXaCf1Vopjmpbri5@stefanha-x1.localdomain> (raw)
In-Reply-To: <54613b7d-8362-380c-f7d8-1a21e83b706d@linaro.org>

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On Thu, Oct 21, 2021 at 03:08:56PM -0700, Richard Henderson wrote:
> On 10/21/21 10:41 AM, Stefan Hajnoczi wrote:
> > The following changes since commit afc9fcde55296b83f659de9da3cdf044812a6eeb:
> > 
> >    Merge remote-tracking branch 'remotes/mst/tags/for_upstream' into staging (2021-10-20 06:10:51 -0700)
> > 
> > are available in the Git repository at:
> > 
> >    https://gitlab.com/stefanha/qemu.git tags/block-pull-request
> > 
> > for you to fetch changes up to 4b2b3d2653f255ef4259a7689af1956536565901:
> > 
> >    coroutine: resize pool periodically instead of limiting size (2021-10-21 18:40:07 +0100)
> > 
> > ----------------------------------------------------------------
> > Pull request
> > 
> > Performance optimization when guest applications submit a lot of parallel I/O.
> > This has also been found to improve clang SafeStack performance.
> > 
> > ----------------------------------------------------------------
> > 
> > Stefan Hajnoczi (1):
> >    coroutine: resize pool periodically instead of limiting size
> > 
> >   include/qemu/coroutine-pool-timer.h | 36 ++++++++++++++++
> >   include/qemu/coroutine.h            |  7 ++++
> >   iothread.c                          |  6 +++
> >   util/coroutine-pool-timer.c         | 35 ++++++++++++++++
> >   util/main-loop.c                    |  5 +++
> >   util/qemu-coroutine.c               | 64 ++++++++++++++++-------------
> >   util/meson.build                    |  1 +
> >   7 files changed, 125 insertions(+), 29 deletions(-)
> >   create mode 100644 include/qemu/coroutine-pool-timer.h
> >   create mode 100644 util/coroutine-pool-timer.c
> 
> This is causing
> 
>  (001/170) tests/acceptance/boot_linux.py:BootLinuxX8664.test_pc_i440fx_tcg:
> INTERRUPTED: Test interrupted by SIGTERM\nRunner error occurred: Timeout
> reached\nOriginal status: ERROR\n{'name':
> '001-tests/acceptance/boot_linux.py:BootLinuxX8664.test_pc_i440fx_tcg',
> 'logdir':
> '/home/richard.henderson/qemu/bld/tests/results/job-2021-10-21T20.58-ae0f6...
> (900.15 s)
>  (002/170) tests/acceptance/boot_linux.py:BootLinuxX8664.test_pc_i440fx_kvm:
> INTERRUPTED: Test interrupted by SIGTERM\nRunner error occurred: Timeout
> reached\nOriginal status: ERROR\n{'name':
> '002-tests/acceptance/boot_linux.py:BootLinuxX8664.test_pc_i440fx_kvm',
> 'logdir':
> '/home/richard.henderson/qemu/bld/tests/results/job-2021-10-21T20.58-ae0f6...
> (900.23 s)
> 
> I initially though this was just gitlab, but it reliably happens on my local machine as well.

Thanks, the coroutine pool timer commit in this pull request is broken.
Coroutines are created in one thread and then destroyed in another, so
the thread-local book keeping that assumed coroutines live in a single
thread was getting out of sync.

I will drop this pull request for now.

Stefan

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