From: Zebediah Figura <z.figura12@gmail.com>
To: "André Almeida" <andrealmeid@collabora.com>,
"Thomas Gleixner" <tglx@linutronix.de>,
"Ingo Molnar" <mingo@redhat.com>,
"Peter Zijlstra" <peterz@infradead.org>,
"Darren Hart" <dvhart@infradead.org>,
linux-kernel@vger.kernel.org,
"Steven Rostedt" <rostedt@goodmis.org>,
"Sebastian Andrzej Siewior" <bigeasy@linutronix.de>
Cc: kernel@collabora.com, krisman@collabora.com,
pgriffais@valvesoftware.com, joel@joelfernandes.org,
malteskarupke@fastmail.fm, linux-api@vger.kernel.org,
fweimer@redhat.com, libc-alpha@sourceware.org,
linux-kselftest@vger.kernel.org, shuah@kernel.org,
acme@kernel.org, corbet@lwn.net, Peter Oskolkov <posk@posk.io>,
Andrey Semashev <andrey.semashev@gmail.com>,
Davidlohr Bueso <dave@stgolabs.net>
Subject: Re: [PATCH v4 00/15] Add futex2 syscalls
Date: Thu, 3 Jun 2021 23:51:41 -0500 [thread overview]
Message-ID: <dab34fd2-b494-8686-bcd7-68beeba4f386@gmail.com> (raw)
In-Reply-To: <20210603195924.361327-1-andrealmeid@collabora.com>
On 6/3/21 2:59 PM, André Almeida wrote:
> ** The wait on multiple problem
>
> The use case lies in the Wine implementation of the Windows NT interface
> WaitMultipleObjects. This Windows API function allows a thread to sleep
> waiting on the first of a set of event sources (mutexes, timers, signal,
> console input, etc) to signal. Considering this is a primitive
> synchronization operation for Windows applications, being able to quickly
> signal events on the producer side, and quickly go to sleep on the
> consumer side is essential for good performance of those running over Wine.
>
I know this is part of the cover letter, but I really do want to clarify
that this isn't really accurate. The use case that this is referring to
is not "the Wine implementation of WaitForMultipleObjects", it is an
out-of-tree implementation of WaitForMultipleObjects that provides
improved performance compared to the in-tree implementation.
This is especially salient because:
(1) this out-of-tree implementation is only in a small handful of cases
any more performant than a different out-of-tree implementation which
uses eventfd and poll() instead;
(2) these implementations will remain out-of-tree due to compatibility
and robustness problems;
(3) I believe there is potential for an upstreamable implementation
which does not rely on futex or futex2.
next prev parent reply other threads:[~2021-06-04 4:51 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-03 19:59 André Almeida
2021-06-03 19:59 ` [PATCH v4 01/15] futex2: Implement wait and wake functions André Almeida
2021-06-03 19:59 ` [PATCH v4 02/15] futex2: Add support for shared futexes André Almeida
2021-06-03 19:59 ` [PATCH v4 03/15] futex2: Implement vectorized wait André Almeida
2021-06-03 19:59 ` [PATCH v4 04/15] futex2: Implement requeue operation André Almeida
2021-06-03 19:59 ` [PATCH v4 05/15] futex2: Implement support for different futex sizes André Almeida
2021-06-06 19:12 ` Davidlohr Bueso
2021-06-06 23:01 ` Andrey Semashev
2021-06-03 19:59 ` [PATCH v4 06/15] futex2: Add compatibility entry point for x86_x32 ABI André Almeida
2021-06-03 19:59 ` [PATCH v4 07/15] docs: locking: futex2: Add documentation André Almeida
2021-06-06 19:23 ` Davidlohr Bueso
2021-06-03 19:59 ` [PATCH v4 08/15] selftests: futex2: Add wake/wait test André Almeida
2021-06-03 19:59 ` [PATCH v4 09/15] selftests: futex2: Add timeout test André Almeida
2021-06-03 19:59 ` [PATCH v4 10/15] selftests: futex2: Add wouldblock test André Almeida
2021-06-03 19:59 ` [PATCH v4 11/15] selftests: futex2: Add waitv test André Almeida
2021-06-03 19:59 ` [PATCH v4 12/15] selftests: futex2: Add requeue test André Almeida
2021-06-03 19:59 ` [PATCH v4 13/15] selftests: futex2: Add futex sizes test André Almeida
2021-06-03 19:59 ` [PATCH v4 14/15] perf bench: Add futex2 benchmark tests André Almeida
2021-06-03 19:59 ` [PATCH v4 15/15] kernel: Enable waitpid() for futex2 André Almeida
2021-06-04 4:51 ` Zebediah Figura [this message]
2021-06-04 17:04 ` [PATCH v4 00/15] Add futex2 syscalls André Almeida
2021-06-04 11:36 ` Nicholas Piggin
2021-06-04 20:01 ` André Almeida
2021-06-05 1:09 ` Nicholas Piggin
2021-06-05 8:56 ` Andrey Semashev
2021-06-06 11:57 ` Nicholas Piggin
2021-06-06 13:15 ` Andrey Semashev
2021-06-08 1:25 ` Nicholas Piggin
2021-06-08 11:03 ` Andrey Semashev
2021-06-08 11:13 ` Greg KH
2021-06-08 11:44 ` Peter Zijlstra
2021-06-08 14:31 ` Davidlohr Bueso
2021-06-08 12:06 ` Andrey Semashev
2021-06-08 12:33 ` Greg KH
2021-06-08 12:35 ` Greg KH
2021-06-08 13:18 ` Andrey Semashev
2021-06-08 13:27 ` Greg KH
2021-06-08 13:41 ` Andrey Semashev
2021-06-08 17:06 ` Zebediah Figura
2021-06-08 14:14 ` André Almeida
2021-06-07 15:40 ` André Almeida
2021-06-08 1:31 ` Nicholas Piggin
2021-06-08 2:33 ` Davidlohr Bueso
2021-06-08 4:45 ` Nicholas Piggin
2021-06-08 12:26 ` Sebastian Andrzej Siewior
2021-06-08 14:23 ` Peter Zijlstra
2021-06-08 14:57 ` Sebastian Andrzej Siewior
2021-06-08 15:04 ` André Almeida
2021-06-08 18:08 ` Adhemerval Zanella
2021-06-08 18:19 ` Florian Weimer
2021-06-08 18:22 ` Adhemerval Zanella
2021-06-09 16:26 ` David Laight
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