From: Andrew Cooper <andrew.cooper3@citrix.com>
To: Jan Beulich <JBeulich@suse.com>
Cc: xen-devel <xen-devel@lists.xenproject.org>,
Malcolm Crossley <malcolm.crossley@citrix.com>,
tim@xen.org, keir@xen.org
Subject: Re: [PATCH v2] Xen: Spread boot time page scrubbing across all available CPU's
Date: Mon, 30 Sep 2013 16:42:56 +0100 [thread overview]
Message-ID: <52499C00.9070905@citrix.com> (raw)
In-Reply-To: <5249B66102000078000F81CA@nat28.tlf.novell.com>
On 30/09/13 16:35, Jan Beulich wrote:
>>>> On 30.09.13 at 15:56, Malcolm Crossley <malcolm.crossley@citrix.com> wrote:
>> The difference between 1 core per node bandwidth and 3 core's per node
>> bandwidth is:
>>
>> AMD: 30000MB/s (1-core) vs 48000MB/s (3-core)
>> Intel: 12000MB/s (1-core) vs 38000MB/s (3-core)
>>
>> So I think it's worth the extra complexity to have multiple core's per
>> node scrubbing memory.
> The numbers are convincing. Which means that the only request
> I'd have is to avoid more than one hyperthread on a core to get
> picked for doing the scrubbing.
>
> Jan
>
Why? Being independent operations, scrubbing like this will still be
sped up by hyperthreading.
As scrubbing RAM is simply a race to get it done as quickly as possible,
unless it can be demonstrated that using all cores is actively
detrimental to the overall time taken, we really should use all cores
where possible.
~Andrew
next prev parent reply other threads:[~2013-09-30 15:43 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-09-30 12:35 [PATCH v2] Xen: Spread boot time page scrubbing across all available CPU's Malcolm Crossley
2013-09-30 13:26 ` Jan Beulich
2013-09-30 13:56 ` Malcolm Crossley
2013-09-30 15:35 ` Jan Beulich
2013-09-30 15:42 ` Andrew Cooper [this message]
2013-09-30 16:08 ` Jan Beulich
2013-09-30 17:43 ` Konrad Rzeszutek Wilk
2013-10-03 11:39 ` Tim Deegan
2014-04-01 19:29 ` Konrad Rzeszutek Wilk
2014-04-03 1:19 ` Konrad Rzeszutek Wilk
2014-04-03 8:35 ` Jan Beulich
2014-04-03 9:00 ` Tim Deegan
2014-04-09 14:20 ` Konrad Rzeszutek Wilk
2014-04-10 11:09 ` Dario Faggioli
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