From: Eric Blake <eblake@redhat.com>
To: Peter Lieven <pl@kamp.de>, Stefan Hajnoczi <stefanha@redhat.com>
Cc: Kevin Wolf <kwolf@redhat.com>,
"Michael S. Tsirkin" <mst@redhat.com>,
Stefan Hajnoczi <stefanha@gmail.com>,
ming.lei@canonical.com,
"qemu-devel@nongnu.org" <qemu-devel@nongnu.org>,
Max Reitz <mreitz@redhat.com>
Subject: Re: [Qemu-devel] value of VIRTQUEUE_MAX_SIZE
Date: Fri, 06 Feb 2015 06:22:41 -0700 [thread overview]
Message-ID: <54D4C021.106@redhat.com> (raw)
In-Reply-To: <54D49B59.2060104@kamp.de>
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On 02/06/2015 03:45 AM, Peter Lieven wrote:
>>> The idea was that IOV_MAX is the limit in case of at least virtio-blk. The host
>>> will not support more than IOV_MAX iovecs passed to a block request.
>> Is there an issue in practice?
>
> If there is no platform where IOV_MAX is less than 1024 then not.
POSIX allows for a system with IOV_MAX as small as 16. But these days,
systems we care about probably have a much larger value; alas, I don't
know off-hand what actual systems use to say if 1024 is a common minimum.
--
Eric Blake eblake redhat com +1-919-301-3266
Libvirt virtualization library http://libvirt.org
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prev parent reply other threads:[~2015-02-06 13:22 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-01-30 21:08 [Qemu-devel] value of VIRTQUEUE_MAX_SIZE Peter Lieven
2015-02-05 14:00 ` Stefan Hajnoczi
2015-02-05 14:29 ` Peter Lieven
2015-02-06 10:42 ` Stefan Hajnoczi
2015-02-06 10:45 ` Peter Lieven
2015-02-06 13:22 ` Eric Blake [this message]
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