From: Dario Faggioli <dario.faggioli@citrix.com>
To: Juergen Gross <jgross@suse.com>,
xen-devel <xen-devel@lists.xenproject.org>
Cc: Wei Liu <wei.liu2@citrix.com>,
Stefano Stabellini <sstabellini@kernel.org>,
Ian Jackson <ian.jackson@eu.citrix.com>
Subject: Re: HVM guest performance regression
Date: Fri, 26 May 2017 19:04:14 +0200 [thread overview]
Message-ID: <1495818254.7393.73.camel@citrix.com> (raw)
In-Reply-To: <55443407-5d99-0830-e8e0-6c2044c18ec9@suse.com>
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On Fri, 2017-05-26 at 18:14 +0200, Juergen Gross wrote:
> Looking for the reason of a performance regression of HVM guests
> under
> Xen 4.7 against 4.5 I found the reason to be commit
> c26f92b8fce3c9df17f7ef035b54d97cbe931c7a ("libxl: remove
> freemem_slack")
> in Xen 4.6.
>
> The problem occurred when dom0 had to be ballooned down when starting
> the guest. The performance of some micro benchmarks dropped by about
> a factor of 2 with above commit.
>
Performance of micro benchmarks run _inside_ the guest, I'm guessing?
> Interesting point is that the performance of the guest will depend on
> the amount of free memory being available at guest creation time.
> When there was barely enough memory available for starting the guest
> the performance will remain low even if memory is being freed later.
>
OOC, what kind of host? Big? Small? NUMA, non-NUMA?, etc
Regards,
Dario
--
<<This happens because I choose it to happen!>> (Raistlin Majere)
-----------------------------------------------------------------
Dario Faggioli, Ph.D, http://about.me/dario.faggioli
Senior Software Engineer, Citrix Systems R&D Ltd., Cambridge (UK)
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next prev parent reply other threads:[~2017-05-26 17:04 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-05-26 16:14 HVM guest performance regression Juergen Gross
2017-05-26 16:19 ` [for-4.9] " Ian Jackson
2017-05-26 17:00 ` Juergen Gross
2017-05-26 19:01 ` Stefano Stabellini
2017-05-29 19:05 ` Juergen Gross
2017-05-30 7:24 ` Jan Beulich
[not found] ` <592D3A3A020000780015D787@suse.com>
2017-05-30 10:33 ` Juergen Gross
2017-05-30 10:43 ` Jan Beulich
[not found] ` <592D68DC020000780015D919@suse.com>
2017-05-30 14:57 ` Juergen Gross
2017-05-30 15:10 ` Jan Beulich
2017-06-06 13:44 ` Juergen Gross
2017-06-06 16:39 ` Stefano Stabellini
2017-06-06 19:00 ` Juergen Gross
2017-06-06 19:08 ` Stefano Stabellini
2017-06-07 6:55 ` Juergen Gross
2017-06-07 18:19 ` Stefano Stabellini
2017-06-08 9:37 ` Juergen Gross
2017-06-08 18:09 ` Stefano Stabellini
2017-06-08 18:28 ` Juergen Gross
2017-06-08 21:00 ` Dario Faggioli
2017-06-11 2:27 ` Konrad Rzeszutek Wilk
2017-06-12 5:48 ` Solved: " Juergen Gross
2017-06-12 7:35 ` Andrew Cooper
2017-06-12 7:47 ` Juergen Gross
2017-06-12 8:30 ` Andrew Cooper
2017-05-26 17:04 ` Dario Faggioli [this message]
2017-05-26 17:25 ` Juergen Gross
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