From: Stefan Hajnoczi <stefanha@gmail.com>
To: Peter Lieven <pl@dlhnet.de>
Cc: Orit Wasserman <owasserm@redhat.com>,
"qemu-devel@nongnu.org" <qemu-devel@nongnu.org>,
Corentin Chary <corentin.chary@gmail.com>,
Paolo Bonzini <pbonzini@redhat.com>
Subject: Re: [Qemu-devel] [RFC] find_next_bit optimizations
Date: Tue, 12 Mar 2013 16:12:18 +0100 [thread overview]
Message-ID: <20130312151218.GA21551@stefanha-thinkpad.redhat.com> (raw)
In-Reply-To: <001482DC-A501-482A-986D-30B04AC9D116@dlhnet.de>
On Tue, Mar 12, 2013 at 09:41:04AM +0100, Peter Lieven wrote:
>
> Am 12.03.2013 um 09:35 schrieb Stefan Hajnoczi <stefanha@gmail.com>:
>
> > On Mon, Mar 11, 2013 at 02:44:03PM +0100, Peter Lieven wrote:
> >> I ever since had a few VMs which are very hard to migrate because of a lot of memory I/O. I found that finding the next dirty bit
> >> seemed to be one of the culprits (apart from removing locking which Paolo is working on).
> >>
> >> I have to following proposal which seems to help a lot in my case. Just wanted to have some feedback.
> >
> > Hi Peter,
> > Do you have any performance numbers for this patch? I'm just curious
> > how big the win is.
>
> Hi Stefan,
>
> please see my recent email to the list with the final patch.
> The win is up to 100%. Worst case execution time (whole
> array is zero) is halved on x86_64.
Thanks!
Stefan
prev parent reply other threads:[~2013-03-12 15:12 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-03-11 13:44 [Qemu-devel] [RFC] find_next_bit optimizations Peter Lieven
2013-03-11 14:04 ` Peter Maydell
2013-03-11 14:14 ` Paolo Bonzini
2013-03-11 14:22 ` Peter Lieven
2013-03-11 14:29 ` Peter Lieven
2013-03-11 14:35 ` Paolo Bonzini
2013-03-11 15:24 ` Peter Lieven
2013-03-11 15:25 ` Peter Maydell
2013-03-11 15:29 ` Paolo Bonzini
2013-03-11 15:37 ` Peter Lieven
2013-03-11 15:58 ` Paolo Bonzini
2013-03-11 17:06 ` ronnie sahlberg
2013-03-11 17:07 ` Paolo Bonzini
2013-03-11 18:20 ` Peter Lieven
2013-03-12 7:32 ` [Qemu-devel] [PATCH] bitops: unroll while loop in find_next_bit() Peter Lieven
2013-03-11 15:37 ` [Qemu-devel] [RFC] find_next_bit optimizations Peter Maydell
2013-03-11 15:41 ` Peter Lieven
2013-03-11 15:42 ` Paolo Bonzini
2013-03-11 15:48 ` Peter Lieven
2013-03-12 8:35 ` Stefan Hajnoczi
2013-03-12 8:41 ` Peter Lieven
2013-03-12 15:12 ` Stefan Hajnoczi [this message]
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