From: Eric Wong <e@80x24.org>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Roman Penyaev <rpenyaev@suse.de>,
Al Viro <viro@zeniv.linux.org.uk>,
Linus Torvalds <torvalds@linux-foundation.org>,
Peter Zijlstra <peterz@infradead.org>,
Azat Khuzhin <azat@libevent.org>,
linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v4 00/14] epoll: support pollable epoll from userspace
Date: Sat, 27 Jul 2019 17:16:57 +0000 [thread overview]
Message-ID: <20190727171657.cisalgn3wfs5opyi@dcvr> (raw)
In-Reply-To: <20190726162208.0a9a244d41d9384fb94d9210@linux-foundation.org>
Andrew Morton <akpm@linux-foundation.org> wrote:
> On Tue, 11 Jun 2019 16:54:44 +0200 Roman Penyaev <rpenyaev@suse.de> wrote:
> > In order to measure polling from userspace libevent was modified [1] and
> > bench_http benchmark (client and server) was used:
> >
> > o EPOLLET, original epoll:
> >
> > 20000 requests in 0.551306 sec. (36277.49 throughput)
> > Each took about 5.54 msec latency
> > 1600000bytes read. 0 errors.
> >
> > o EPOLLET + polling from userspace:
> >
> > 20000 requests in 0.475585 sec. (42053.47 throughput)
> > Each took about 4.78 msec latency
> > 1600000bytes read. 0 errors.
>
> It would be useful to include some words which describe the
> significance of this to real-world userspace. If a real application is
> sped up 0.000000001% then this isn't very exciting ;)
Agreed. I've put my wfcqueue changes from years back on hold
because I couldn't show a meaningful improvement in real-world
cases: https://lore.kernel.org/lkml/20130401183118.GA9968@dcvr.yhbt.net/
Roman's changes have me interested in seeing how my previous
changes would stack up (no UAPI changes required).
I've been looking for time to forward port my wfcqueue work
to the current kernel (but public-inbox takes priority;
not that I have much time for that).
On the userspace side; I'm not sure any widely-used open source
project is really impacted by epoll performance...
Most everybody seems to use level-trigger :<
prev parent reply other threads:[~2019-07-27 17:16 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-11 14:54 [PATCH v4 00/14] epoll: support pollable epoll from userspace Roman Penyaev
2019-06-11 14:54 ` [PATCH v4 01/14] epoll: move private helpers from a header to the source Roman Penyaev
2019-06-11 14:54 ` [PATCH v4 02/14] epoll: introduce user structures for polling from userspace Roman Penyaev
2019-06-11 14:54 ` [PATCH v4 03/14] epoll: allocate user header and user events ring " Roman Penyaev
2019-06-11 14:54 ` [PATCH v4 04/14] epoll: some sanity flags checks for epoll syscalls " Roman Penyaev
2019-06-11 14:54 ` [PATCH v4 05/14] epoll: offload polling to a work in case of epfd polled " Roman Penyaev
2019-06-11 14:54 ` [PATCH v4 06/14] epoll: introduce helpers for adding/removing events to uring Roman Penyaev
2019-06-11 14:54 ` [PATCH v4 07/14] epoll: call ep_add_event_to_uring() from ep_poll_callback() Roman Penyaev
2019-06-11 14:54 ` [PATCH v4 08/14] epoll: support polling from userspace for ep_insert() Roman Penyaev
2019-06-11 14:54 ` [PATCH v4 09/14] epoll: support polling from userspace for ep_remove() Roman Penyaev
2019-06-11 14:54 ` [PATCH v4 10/14] epoll: support polling from userspace for ep_modify() Roman Penyaev
2019-06-11 14:54 ` [PATCH v4 11/14] epoll: support polling from userspace for ep_poll() Roman Penyaev
2019-06-11 14:54 ` [PATCH v4 12/14] epoll: support mapping for epfd when polled from userspace Roman Penyaev
2019-06-11 14:54 ` [PATCH v4 13/14] epoll: implement epoll_create2() syscall Roman Penyaev
2019-06-11 14:54 ` [PATCH v4 14/14] kselftest: add uepoll-test which tests polling from userspace Roman Penyaev
2019-07-26 23:22 ` [PATCH v4 00/14] epoll: support pollable epoll " Andrew Morton
2019-07-27 17:16 ` Eric Wong [this message]
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