From mboxrd@z Thu Jan  1 00:00:00 1970
From: Avi Kivity <avi@redhat.com>
Subject: Re: KVM lock contention on 48 core AMD machine
Date: Mon, 21 Mar 2011 20:14:39 +0200
Message-ID: <4D87958F.30104@redhat.com>
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Cc: ben@iagu.net, KVM list <kvm@vger.kernel.org>
To: Eric Dumazet <eric.dumazet@gmail.com>
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On 03/21/2011 07:12 PM, Eric Dumazet wrote:
> Le lundi 21 mars 2011 =C3=A0 19:02 +0200, Avi Kivity a =C3=A9crit :
>
> >  Any ideas on how to fix it?  We could pre-allocate IDs and batch t=
hem in
> >  per-cpu caches, but it seems like a lot of work.
> >
>
> Hmm, I dont know what syscalls kvm do, but even a timer_gettime() has=
 to
> lock this idr_lock.

It's qemu playing with posix timers, nothing to do with kvm per se.

> Sounds crazy, and should be fixed in kernel code, not kvm ;)
>

Oh yes, I couldn't fix it in kvm if I wanted to (and I don't want to).

--=20
I have a truly marvellous patch that fixes the bug which this
signature is too narrow to contain.