From: Paolo Bonzini <pbonzini@redhat.com>
To: Thomas Fjellstrom <thomas@fjellstrom.ca>,
Stefan Hajnoczi <stefanha@gmail.com>
Cc: kvm@vger.kernel.org
Subject: Re: virtio disk host cpu overhead?
Date: Sat, 11 Mar 2017 17:45:35 +0100 [thread overview]
Message-ID: <bdbda4f5-ad0f-1ae7-dcc9-ead343d05e3a@redhat.com> (raw)
In-Reply-To: <2460727.SVSaYC5RoY@natasha>
On 11/03/2017 17:33, Thomas Fjellstrom wrote:
>> If the answer to both questions is no, then QEMU uses a thread pool for
>> disk I/O and those threads could be scheduled on any host CPU.
> But should they be pegging 4 or more cores, when the host can do the same work
> with a single core? I don't mind it spreading work out. But using 4x the cpu
> time to do the same work is a bit much.
I would expect 2x, but not really more than that. Which threads are
doing all the work, beyond the VCPU thread and the host I/O thread?
Paolo
prev parent reply other threads:[~2017-03-11 16:45 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-03 17:05 virtio disk host cpu overhead? Thomas Fjellstrom
2017-03-10 1:52 ` Stefan Hajnoczi
2017-03-11 16:33 ` Thomas Fjellstrom
2017-03-11 16:45 ` Paolo Bonzini [this message]
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