From: Benjamin LaHaise <bcrl@redhat.com>
To: Davide Libenzi <davidel@xmailserver.org>
Cc: Shailabh Nagar <nagar@watson.ibm.com>,
linux-kernel <linux-kernel@vger.kernel.org>,
linux-aio <linux-aio@kvack.org>, Andrew Morton <akpm@digeo.com>,
David Miller <davem@redhat.com>,
Linus Torvalds <torvalds@transmeta.com>,
Stephen Tweedie <sct@redhat.com>
Subject: Re: [PATCH] async poll for 2.5
Date: Tue, 15 Oct 2002 15:12:38 -0400 [thread overview]
Message-ID: <20021015151238.L14596@redhat.com> (raw)
In-Reply-To: <Pine.LNX.4.44.0210151213170.1554-100000@blue1.dev.mcafeelabs.com>; from davidel@xmailserver.org on Tue, Oct 15, 2002 at 12:16:39PM -0700
On Tue, Oct 15, 2002 at 12:16:39PM -0700, Davide Libenzi wrote:
> Ben, one of the reasons of the /dev/epoll speed is how it returns events
> and how it collapses them. A memory mapped array is divided by two and
> while the user consumes events in one set, the kernel fill the other one.
> The next wait() will switch the pointers. There is no copy from kernel to
> user space. Doing :
>
> int sys_epoll_wait(int epd, struct pollfd **pevts, int timeout);
>
> the only data the kernel has to copy to userspace is the 4(8) bytes for
> the "pevts" pointer.
Erm, the aio interface has support for the event ringbuffer being accessed
by userspace (it lives in user memory and the kernel acts as a writer, with
userspace as a reader), that's one of its advantages -- completion events
are directly accessible from userspace after being written to by an
interrupt. Ideally this is to be wrapped in a vsyscall, but we don't have
support for that yet on x86, although much of the code written for x86-64
should be reusable.
-ben
next prev parent reply other threads:[~2002-10-15 19:06 UTC|newest]
Thread overview: 138+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-10-14 22:36 Shailabh Nagar
2002-10-14 22:54 ` John Myers
2002-10-15 15:05 ` Benjamin LaHaise
2002-10-15 17:06 ` Dan Kegel
2002-10-15 17:03 ` Benjamin LaHaise
2002-10-15 17:18 ` Dan Kegel
2002-10-16 2:11 ` Lincoln Dale
2002-10-15 18:09 ` Shailabh Nagar
2002-10-15 18:53 ` Dan Kegel
2002-10-15 18:57 ` Benjamin LaHaise
2002-10-15 20:25 ` John Gardiner Myers
2002-10-15 21:09 ` Dan Kegel
2002-10-15 21:50 ` John Myers
2002-10-15 22:33 ` Davide Libenzi
2002-10-15 22:56 ` John Gardiner Myers
2002-10-15 23:23 ` Davide Libenzi
2002-10-16 19:16 ` John Myers
2002-10-15 21:11 ` Davide Libenzi
2002-10-15 22:01 ` John Gardiner Myers
2002-10-15 22:27 ` Davide Libenzi
2002-10-15 22:36 ` John Gardiner Myers
2002-10-15 22:41 ` Benjamin LaHaise
2002-10-15 23:26 ` John Gardiner Myers
2002-10-15 23:05 ` Davide Libenzi
2002-10-15 23:33 ` John Gardiner Myers
2002-10-16 0:05 ` Davide Libenzi
2002-10-16 0:15 ` John Myers
2002-10-16 14:25 ` Davide Libenzi
2002-10-16 18:15 ` John Gardiner Myers
2002-10-16 19:20 ` Davide Libenzi
2002-10-16 23:31 ` epoll (was Re: [PATCH] async poll for 2.5) John Gardiner Myers
2002-10-16 23:51 ` Davide Libenzi
2002-10-17 18:06 ` John Gardiner Myers
2002-10-17 18:33 ` Davide Libenzi
2002-10-18 19:02 ` John Gardiner Myers
2002-10-18 19:52 ` Davide Libenzi
2002-10-19 0:55 ` John Myers
2002-10-19 5:40 ` Davide Libenzi
2002-10-19 6:59 ` Mark Mielke
2002-10-19 17:26 ` Davide Libenzi
2002-10-19 17:48 ` Dan Kegel
2002-10-19 18:52 ` Charles 'Buck' Krasic
2002-10-19 20:18 ` Charles 'Buck' Krasic
2002-10-19 21:08 ` Dan Kegel
2002-10-22 19:35 ` John Gardiner Myers
2002-10-22 20:06 ` Davide Libenzi
2002-10-22 21:54 ` Erich Nahum
2002-10-22 22:17 ` Dan Kegel
2002-10-22 22:25 ` Davide Libenzi
2002-10-18 21:01 ` Charles 'Buck' Krasic
2002-10-18 21:33 ` Davide Libenzi
2002-10-19 1:05 ` John Myers
2002-10-19 1:27 ` Tervel Atanassov
2002-10-19 18:52 ` John G. Myers
2002-10-19 4:07 ` Charles 'Buck' Krasic
2002-10-16 20:06 ` [PATCH] async poll for 2.5 Mark Mielke
2002-10-16 23:48 ` epoll (was Re: [PATCH] async poll for 2.5) John Gardiner Myers
2002-10-17 0:23 ` Davide Libenzi
2002-10-17 17:45 ` John Myers
2002-10-16 2:45 ` [PATCH] async poll for 2.5 Charles 'Buck' Krasic
2002-10-16 14:28 ` Davide Libenzi
2002-10-17 18:47 ` Charles 'Buck' Krasic
2002-10-17 19:20 ` Davide Libenzi
2002-10-18 3:30 ` Dan Kegel
2002-10-16 18:29 ` John Gardiner Myers
2002-10-16 20:39 ` Charles 'Buck' Krasic
2002-10-17 17:59 ` epoll (was Re: [PATCH] async poll for 2.5) John Gardiner Myers
2002-10-21 16:58 ` [PATCH] async poll for 2.5 Alan Cox
2002-10-21 16:50 ` Benjamin LaHaise
2002-10-16 19:59 ` Dan Kegel
2002-10-16 20:03 ` Dan Kegel
2002-10-17 17:43 ` epoll (was Re: [PATCH] async poll for 2.5) John Myers
2002-10-18 17:00 ` Mark Mielke
2002-10-18 17:28 ` Dan Kegel
2002-10-18 17:41 ` Davide Libenzi
2002-10-18 18:55 ` Mark Mielke
2002-10-18 19:16 ` Davide Libenzi
2002-10-19 6:56 ` Mark Mielke
2002-10-19 16:10 ` Charles 'Buck' Krasic
2002-10-22 17:22 ` Mark Mielke
2002-10-22 17:46 ` Dan Kegel
2002-10-22 17:47 ` Davide Libenzi
2002-10-22 18:13 ` Alan Cox
2002-10-22 18:18 ` Davide Libenzi
2002-10-22 18:37 ` Benjamin LaHaise
2002-10-22 19:22 ` John Gardiner Myers
2002-10-22 19:28 ` Benjamin LaHaise
2002-10-22 19:50 ` John Gardiner Myers
2002-10-22 20:00 ` Benjamin LaHaise
2002-10-22 20:23 ` async poll John Myers
2002-10-23 11:10 ` Latest aio code (was Re: [PATCH] async poll for 2.5) Suparna Bhattacharya
2002-10-22 19:49 ` epoll " Davide Libenzi
2002-10-22 18:42 ` Charles 'Buck' Krasic
2002-10-22 19:35 ` Davide Libenzi
2002-10-23 16:49 ` Dan Kegel
2002-10-23 17:39 ` Benjamin LaHaise
2002-10-23 18:47 ` Davide Libenzi
2002-10-23 21:18 ` Benjamin LaHaise
2002-10-23 21:35 ` Davide Libenzi
2002-10-23 21:39 ` John Gardiner Myers
2002-10-23 21:54 ` Davide Libenzi
2002-10-23 17:49 ` Charles 'Buck' Krasic
2002-10-23 18:14 ` Davide Libenzi
2002-10-23 18:32 ` Charles 'Buck' Krasic
2002-10-23 20:36 ` async poll John Myers
2002-10-23 20:57 ` Dan Kegel
2002-10-23 21:23 ` John Gardiner Myers
2002-10-23 21:51 ` Davide Libenzi
2002-10-23 21:51 ` bert hubert
2002-10-23 22:10 ` Davide Libenzi
2002-10-23 21:54 ` John Gardiner Myers
2002-10-23 22:22 ` Davide Libenzi
2002-10-23 22:29 ` John Gardiner Myers
2002-10-23 22:50 ` Davide Libenzi
2002-10-24 7:32 ` Eduardo Pérez
2002-10-24 15:05 ` Charles 'Buck' Krasic
2002-10-23 22:24 ` Dan Kegel
2002-10-23 22:30 ` Davide Libenzi
2002-10-23 22:53 ` Davide Libenzi
2002-10-23 21:13 ` Charles 'Buck' Krasic
2002-10-19 17:19 ` epoll (was Re: [PATCH] async poll for 2.5) Davide Libenzi
2002-10-18 18:55 ` Chris Friesen
2002-10-18 19:00 ` Mark Mielke
2002-10-15 17:38 ` [PATCH] async poll for 2.5 Shailabh Nagar
2002-10-15 17:50 ` Benjamin LaHaise
2002-10-15 18:16 ` Davide Libenzi
2002-10-15 18:18 ` Shailabh Nagar
2002-10-15 19:00 ` Davide Libenzi
2002-10-15 19:02 ` Benjamin LaHaise
2002-10-15 18:59 ` Shailabh Nagar
2002-10-15 19:16 ` Davide Libenzi
2002-10-15 19:12 ` Benjamin LaHaise [this message]
2002-10-15 19:31 ` Davide Libenzi
2002-10-15 19:38 ` Dan Kegel
2002-10-15 19:55 ` Davide Libenzi
2002-10-15 20:36 ` John Gardiner Myers
2002-10-15 20:39 ` Benjamin LaHaise
2002-10-15 19:02 ` Davide Libenzi
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