linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Jason Baron <jbaron@akamai.com>
To: Fam Zheng <famz@redhat.com>, linux-kernel@vger.kernel.org
Cc: Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
	x86@kernel.org, Alexander Viro <viro@zeniv.linux.org.uk>,
	Andrew Morton <akpm@linux-foundation.org>,
	Kees Cook <keescook@chromium.org>,
	Andy Lutomirski <luto@amacapital.net>,
	David Herrmann <dh.herrmann@gmail.com>,
	Alexei Starovoitov <ast@plumgrid.com>,
	Miklos Szeredi <mszeredi@suse.cz>,
	David Drysdale <drysdale@google.com>,
	Oleg Nesterov <oleg@redhat.com>,
	"David S. Miller" <davem@davemloft.net>,
	Vivek Goyal <vgoyal@redhat.com>,
	Mike Frysinger <vapier@gentoo.org>,
	"Theodore Ts'o" <tytso@mit.edu>,
	Heiko Carstens <heiko.carstens@de.ibm.com>,
	Rasmus Villemoes <linux@rasmusvillemoes.dk>,
	Rashika Kheria <rashika.kheria@gmail.com>,
	Hugh Dickins <hughd@google.com>,
	Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
	Peter Zijlstra <peterz@infradead.org>,
	linux-fsdevel@vger.kernel.org, linux-api@vger.kernel.org,
	Josh Triplett <josh@joshtriplett.org>,
	"Michael Kerrisk (man-pages)" <mtk.manpages@gmail.com>,
	Paolo Bonzini <pbonzini@redhat.com>,
	Omar Sandoval <osandov@osandov.com>,
	Jonathan Corbet <corbet@lwn.net>,
	shane.seymour@hp.com, dan.j.rosenberg@gmail.com
Subject: Re: [PATCH v4 0/9] epoll: Introduce new syscalls, epoll_ctl_batch and epoll_pwait1
Date: Thu, 12 Mar 2015 11:02:03 -0400	[thread overview]
Message-ID: <5501AA6B.2020209@akamai.com> (raw)
In-Reply-To: <1425952155-27603-1-git-send-email-famz@redhat.com>

On 03/09/2015 09:49 PM, Fam Zheng wrote:
>
> Benchmark for epoll_pwait1
> ==========================
>
> By running fio tests inside VM with both original and modified QEMU, we can
> compare their difference in performance.
>
> With a small VM setup [t1], the original QEMU (ppoll based) has an 4k read
> latency overhead around 37 us. In this setup, the main loop polls 10~20 fds.
>
> With a slightly larger VM instance [t2] - attached a virtio-serial device so
> that there are 80~90 fds in the main loop - the original QEMU has a latency
> overhead around 49 us. By adding more such devices [t3], we can see the latency
> go even higher - 83 us with ~200 FDs.
>
> Now modify QEMU to use epoll_pwait1 and test again, the latency numbers are
> repectively 36us, 37us, 47us for t1, t2 and t3.
>
>

Hi,

So it sounds like you are comparing original qemu code (which was using
ppoll) vs. using epoll with these new syscalls. Curious if you have numbers
comparing the existing epoll (with say the timerfd in your epoll set), so
we can see the improvement relative to epoll.

Thanks,

-Jason

  parent reply	other threads:[~2015-03-12 15:02 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-03-10  1:49 [PATCH v4 0/9] epoll: Introduce new syscalls, epoll_ctl_batch and epoll_pwait1 Fam Zheng
2015-03-10  1:49 ` [PATCH v4 1/9] epoll: Extract epoll_wait_do and epoll_pwait_do Fam Zheng
2015-03-10  1:49 ` [PATCH v4 2/9] epoll: Specify clockid explicitly Fam Zheng
2015-03-10  1:49 ` [PATCH v4 3/9] epoll: Extract ep_ctl_do Fam Zheng
2015-03-10  1:49 ` [PATCH v4 4/9] epoll: Add implementation for epoll_ctl_batch Fam Zheng
2015-03-10 13:59   ` Dan Rosenberg
2015-03-11  2:23     ` Fam Zheng
2015-03-10  1:49 ` [PATCH v4 5/9] x86: Hook up epoll_ctl_batch syscall Fam Zheng
2015-03-10  1:49 ` [PATCH v4 6/9] epoll: Add implementation for epoll_pwait1 Fam Zheng
2015-03-10  1:49 ` [PATCH v4 7/9] x86: Hook up epoll_pwait1 syscall Fam Zheng
2015-03-10  1:49 ` [PATCH v4 8/9] epoll: Add compat version implementation of epoll_pwait1 Fam Zheng
2015-03-10  1:49 ` [PATCH v4 9/9] x86: Hook up 32 bit compat epoll_pwait1 syscall Fam Zheng
2015-03-12 15:02 ` Jason Baron [this message]
2015-03-13 11:31   ` [PATCH v4 0/9] epoll: Introduce new syscalls, epoll_ctl_batch and epoll_pwait1 Fam Zheng
2015-03-13 14:46     ` Jason Baron
2015-03-13 14:56       ` Paolo Bonzini

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=5501AA6B.2020209@akamai.com \
    --to=jbaron@akamai.com \
    --cc=akpm@linux-foundation.org \
    --cc=ast@plumgrid.com \
    --cc=corbet@lwn.net \
    --cc=dan.j.rosenberg@gmail.com \
    --cc=davem@davemloft.net \
    --cc=dh.herrmann@gmail.com \
    --cc=drysdale@google.com \
    --cc=famz@redhat.com \
    --cc=heiko.carstens@de.ibm.com \
    --cc=hpa@zytor.com \
    --cc=hughd@google.com \
    --cc=josh@joshtriplett.org \
    --cc=keescook@chromium.org \
    --cc=linux-api@vger.kernel.org \
    --cc=linux-fsdevel@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux@rasmusvillemoes.dk \
    --cc=luto@amacapital.net \
    --cc=mathieu.desnoyers@efficios.com \
    --cc=mingo@redhat.com \
    --cc=mszeredi@suse.cz \
    --cc=mtk.manpages@gmail.com \
    --cc=oleg@redhat.com \
    --cc=osandov@osandov.com \
    --cc=pbonzini@redhat.com \
    --cc=peterz@infradead.org \
    --cc=rashika.kheria@gmail.com \
    --cc=shane.seymour@hp.com \
    --cc=tglx@linutronix.de \
    --cc=tytso@mit.edu \
    --cc=vapier@gentoo.org \
    --cc=vgoyal@redhat.com \
    --cc=viro@zeniv.linux.org.uk \
    --cc=x86@kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).