From: Andrew Cooper <andrew.cooper3@citrix.com>
To: Steven Haigh <netwiz@crc.id.au>
Cc: Roger Pau Monne <roger.pau@citrix.com>,
Jan Beulich <JBeulich@suse.com>,
"xen-devel@lists.xen.org" <xen-devel@lists.xen.org>
Subject: Re: 4.2.1: Poor write performance for DomU.
Date: Wed, 20 Feb 2013 11:06:01 +0000 [thread overview]
Message-ID: <5124AE19.2000802@citrix.com> (raw)
In-Reply-To: <5124AF9F02000078000BFA35@nat28.tlf.novell.com>
On 20/02/13 10:12, Jan Beulich wrote:
>>>> On 20.02.13 at 10:49, Steven Haigh <netwiz@crc.id.au> wrote:
>> My build of Xen 4.2.1 also has all of the recent security advisories
>> patched as well. Although it is interesting to note that downgrading to
>> Xen 4.1.2 made no difference to write speeds.
> Not surprising at all, considering that the hypervisor is only a passive
> library for all PV I/O purposes. You're likely hunting for a kernel side
> regression (and hence the mentioning of the hypervisor version as
> the main factor in the subject is probably misleading).
>
> Jan
Further to this, do try to verify if your disk driver has changed
recently to use >0 order page allocations for DMA. If it has, then
speed will be much slower as there will now be the swiotlb cpu-copy
overhead.
~Andrew
>
>
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xen.org
> http://lists.xen.org/xen-devel
next prev parent reply other threads:[~2013-02-20 11:06 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-02-20 2:10 4.2.1: Poor write performance for DomU Steven Haigh
2013-02-20 8:26 ` Roger Pau Monné
2013-02-20 8:49 ` Steven Haigh
2013-02-20 9:49 ` Steven Haigh
2013-02-20 10:12 ` Jan Beulich
2013-02-20 11:06 ` Andrew Cooper [this message]
2013-02-20 11:08 ` Steven Haigh
2013-02-20 12:48 ` Andrew Cooper
2013-02-20 13:18 ` Pasi Kärkkäinen
2013-03-08 20:42 ` Konrad Rzeszutek Wilk
2013-03-08 8:54 ` Steven Haigh
2013-03-08 9:43 ` Roger Pau Monné
2013-03-08 9:46 ` Steven Haigh
2013-03-08 9:54 ` Roger Pau Monné
2013-03-08 20:49 ` Konrad Rzeszutek Wilk
2013-03-08 22:30 ` Steven Haigh
2013-03-11 13:30 ` Konrad Rzeszutek Wilk
2013-03-11 13:37 ` Steven Haigh
2013-03-12 13:04 ` Konrad Rzeszutek Wilk
2013-03-12 14:08 ` Steven Haigh
[not found] ` <514EA337.7030303@crc.id.au>
[not found] ` <514EA6B0.8010504@crc.id.au>
[not found] ` <514EA741.7050403@crc.id.au>
2013-03-24 9:10 ` Steven Haigh
2013-03-24 9:54 ` Steven Haigh
2013-03-25 2:21 ` Steven Haigh
2013-08-20 16:48 ` Konrad Rzeszutek Wilk
2013-08-20 18:25 ` Steven Haigh
2013-09-05 8:28 ` Steven Haigh
2013-09-06 13:33 ` Konrad Rzeszutek Wilk
2013-09-06 23:06 ` Steven Haigh
2013-09-06 23:37 ` Konrad Rzeszutek Wilk
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