From: Avi Kivity <avi@redhat.com>
To: Jan Kiszka <jan.kiszka@siemens.com>
Cc: Kevin Wolf <kwolf@redhat.com>,
Anthony Liguori <aliguori@us.ibm.com>,
Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>,
Marcelo Tosatti <mtosatti@redhat.com>,
qemu-devel <qemu-devel@nongnu.org>
Subject: Re: [Qemu-devel] [PATCH] Use qemu_eventfd for POSIX AIO
Date: Tue, 27 Sep 2011 17:34:18 +0300 [thread overview]
Message-ID: <4E81DEEA.10208@redhat.com> (raw)
In-Reply-To: <4E81DDDF.8050201@siemens.com>
On 09/27/2011 05:29 PM, Jan Kiszka wrote:
> >
> > Moreover, the eventfd() counter is not lossy (practically speaking) whereas if
> > you use pipe() as a counter, it will be lossy in practice.
> >
> > This is why posix aio uses pipe() and not eventfd().
>
> I don't get this yet. eventfd is lossy by default. It only decreases the
> counter on read if you specify EFD_SEMAPHORE - which we do not do.
>
It's not lossy - a read returns the number of events written since the
last read.
--
error compiling committee.c: too many arguments to function
next prev parent reply other threads:[~2011-09-27 14:34 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-09-20 16:49 [PATCH] qemu-kvm: Switch POSIX compat AIO implementation to upstream Jan Kiszka
2011-09-21 8:06 ` Stefan Hajnoczi
2011-09-26 17:23 ` Jan Kiszka
2011-09-26 17:24 ` Avi Kivity
2011-09-26 18:09 ` Anthony Liguori
2011-09-27 9:00 ` Avi Kivity
2011-09-27 13:56 ` [Qemu-devel] [PATCH] Use qemu_eventfd for POSIX AIO Jan Kiszka
2011-09-27 14:07 ` Anthony Liguori
2011-09-27 14:11 ` Avi Kivity
2011-09-27 14:19 ` Anthony Liguori
2011-09-27 14:22 ` Avi Kivity
2011-09-27 14:22 ` Jan Kiszka
2011-09-27 14:38 ` Anthony Liguori
2011-09-27 14:29 ` Jan Kiszka
2011-09-27 14:34 ` Avi Kivity [this message]
2011-09-27 14:36 ` Jan Kiszka
2011-09-27 14:42 ` Avi Kivity
2011-09-27 14:45 ` Jan Kiszka
2011-09-27 14:48 ` Avi Kivity
2011-09-27 14:50 ` Jan Kiszka
2011-09-27 14:54 ` Avi Kivity
2011-09-27 14:57 ` Anthony Liguori
2011-09-27 14:59 ` Jan Kiszka
2011-09-27 14:36 ` Anthony Liguori
2011-09-27 14:41 ` Paolo Bonzini
2011-09-21 8:16 ` [PATCH] qemu-kvm: Switch POSIX compat AIO implementation to upstream Kevin Wolf
2011-09-26 16:56 ` Avi Kivity
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