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From: Jamie Lokier <jamie@shareable.org>
To: "Daniel P. Berrange" <berrange@redhat.com>
Cc: libvir-list@redhat.com, Jan Kiszka <jan.kiszka@web.de>,
	qemu-devel@nongnu.org, Hollis Blanchard <hollisb@us.ibm.com>
Subject: Re: [Qemu-devel] Re: [libvirt] Re: [PATCH 2/3] Introduce monitor 'wait' command
Date: Thu, 9 Apr 2009 18:13:41 +0100	[thread overview]
Message-ID: <20090409171341.GE14196@shareable.org> (raw)
In-Reply-To: <20090409095511.GE18054@redhat.com>

Daniel P. Berrange wrote:
> One scheme would be to have a small buffer - enough to store say 10 events.
> If the monitor is blocking for write, and the buffer is full then start to
> discard all further events. When the buffer has more space again, then
> send an explicit 'overflow' event informing the app that stuff has been 
> dropped from the event queue.
>
> In normal circumstances the app would never see this message, but if there
> was some unexpected problem causing the app to not process events quickly
> enough, then at least it would be able to then detect that qemu has
> discarded alot of events, and re-synchronize its state by running appropriate
> 'info' commands.

This is pretty much what Linux real-time queued I/O signals do.
It's ugly but works. :-)

-- Jamie

  reply	other threads:[~2009-04-09 17:13 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-04-08 14:16 [Qemu-devel] [PATCH 1/3] Allow multiple monitor devices Anthony Liguori
2009-04-08 14:16 ` [Qemu-devel] [PATCH 2/3] Introduce monitor 'wait' command Anthony Liguori
2009-04-08 14:33   ` [Qemu-devel] " Daniel P. Berrange
2009-04-08 14:39     ` Anthony Liguori
2009-04-08 15:03     ` [Qemu-devel] Re: [libvirt] " Gerd Hoffmann
2009-04-08 15:25       ` Jan Kiszka
2009-04-08 17:44       ` Anthony Liguori
2009-04-08 19:06         ` Jamie Lokier
2009-04-08 19:35           ` Anthony Liguori
2009-04-08 20:28             ` Hollis Blanchard
2009-04-08 21:14               ` Anthony Liguori
2009-04-08 21:31                 ` Hollis Blanchard
2009-04-09 13:59                   ` Anthony Liguori
2009-04-08 21:39                 ` Paul Brook
2009-04-09  8:24                   ` Avi Kivity
2009-04-09 13:56                   ` Anthony Liguori
2009-04-09 17:12                     ` Jamie Lokier
2009-04-08 21:27             ` Zachary Amsden
2009-04-09  9:55           ` Daniel P. Berrange
2009-04-09 17:13             ` Jamie Lokier [this message]
2009-04-09  9:44         ` Gerd Hoffmann
2009-04-09 13:31           ` Anthony Liguori
2009-04-08 14:16 ` [Qemu-devel] [PATCH 3/3] Implement vm-state notifications Anthony Liguori
2009-04-08 14:27 ` [Qemu-devel] Re: [PATCH 1/3] Allow multiple monitor devices Jan Kiszka

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