From: Avi Kivity <avi@redhat.com>
To: Andi Kleen <andi@firstfloor.org>
Cc: Andre Przywara <andre.przywara@amd.com>, kvm@vger.kernel.org
Subject: Re: [PATCH 0/3] KVM-userspace: add NUMA support for guests
Date: Sat, 29 Nov 2008 20:43:35 +0200 [thread overview]
Message-ID: <49318D57.6040601@redhat.com> (raw)
In-Reply-To: <87fxlcxo62.fsf@basil.nowhere.org>
Andi Kleen wrote:
> It depends -- it's not necessarily an improvement. e.g. if it leads to
> some CPUs being idle while others are oversubscribed because of the
> pinning you typically lose more than you win. In general default
> pinning is a bad idea in my experience.
>
> Alternative more flexible strategies:
>
> - Do a mapping from CPU to node at runtime by using getcpu()
> - Migrate to complete nodes using migrate_pages when qemu detects
> node migration on the host.
>
Wouldn't that cause lots of migrations? Migrating a 1GB guest can take
a huge amount of cpu time (tens or even hundreds of milliseconds?)
compared to very high frequency activity like the scheduler.
--
I have a truly marvellous patch that fixes the bug which this
signature is too narrow to contain.
next prev parent reply other threads:[~2008-11-29 18:43 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-11-27 22:23 [PATCH 0/3] KVM-userspace: add NUMA support for guests Andre Przywara
2008-11-28 8:14 ` Andi Kleen
2008-11-29 18:43 ` Avi Kivity [this message]
2008-11-29 20:10 ` Andi Kleen
2008-11-29 20:35 ` Avi Kivity
2008-11-30 15:41 ` Andi Kleen
2008-11-30 15:38 ` Avi Kivity
2008-11-30 16:05 ` Andi Kleen
2008-11-30 16:38 ` Avi Kivity
2008-11-30 17:04 ` Andi Kleen
2008-11-30 17:11 ` Avi Kivity
2008-11-30 17:42 ` Andi Kleen
2008-11-30 18:07 ` Avi Kivity
2008-11-30 18:55 ` Andi Kleen
2008-11-30 19:11 ` Skywing
2008-11-30 20:08 ` Avi Kivity
2008-11-30 20:07 ` Avi Kivity
2008-11-30 21:41 ` Andi Kleen
2008-11-30 21:50 ` Avi Kivity
2008-11-30 22:08 ` Skywing
2008-11-28 10:40 ` Daniel P. Berrange
2008-11-29 18:29 ` Avi Kivity
2008-12-01 14:15 ` Andre Przywara
2008-12-01 14:29 ` Avi Kivity
2008-12-01 15:27 ` Anthony Liguori
2008-12-01 15:34 ` Anthony Liguori
2008-12-01 15:37 ` Avi Kivity
2008-12-01 15:49 ` Anthony Liguori
2008-12-01 14:44 ` Daniel P. Berrange
2008-12-01 14:53 ` Avi Kivity
2008-12-01 15:18 ` Anthony Liguori
2008-12-01 15:35 ` Avi Kivity
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