From: Avi Kivity <avi@redhat.com>
To: Jan Kiszka <jan.kiszka@web.de>
Cc: "Alexander Graf" <agraf@suse.de>,
"Michael Tokarev" <mjt@tls.msk.ru>,
"René Pfeiffer" <lynx@luchs.at>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>
Subject: Re: I/O performance of VirtIO
Date: Mon, 26 Oct 2009 10:35:49 +0200 [thread overview]
Message-ID: <4AE55F65.7050906@redhat.com> (raw)
In-Reply-To: <4AE559FC.4060400@web.de>
On 10/26/2009 10:12 AM, Jan Kiszka wrote:
>> No. Dedicated I/O threads provide parallelism. All latency needs is to
>> have SIGIO sent on all file descriptors (or rather, in qemu-kvm with
>> irqchip, to have all file descriptors in the poll() call).
>>
>> Jan, does slirp add new connections to the select set?
>>
>>
> It should do so in slirp_select_fill (it iterates over all TCP&UDP
> sockets of all instances). I think without doing this, slirp wouldn't
> receive a single bit at all (no activity without FD_ISSET).
>
Yes, so it seems from the code. But something is missing if you get
better performance with -no-kvm-irqchip. Perhaps timers are off.
--
error compiling committee.c: too many arguments to function
prev parent reply other threads:[~2009-10-26 8:36 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-10-12 20:49 I/O performance of VirtIO René Pfeiffer
2009-10-12 21:45 ` Michael Tokarev
2009-10-12 21:54 ` René Pfeiffer
2009-10-13 6:35 ` Jan Kiszka
2009-10-22 16:29 ` Avi Kivity
2009-10-22 22:06 ` Alexander Graf
2009-10-25 5:44 ` Avi Kivity
2009-10-26 8:12 ` Jan Kiszka
2009-10-26 8:35 ` Avi Kivity [this message]
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