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From: Wei Liu <wei.liu2@citrix.com>
To: David Vrabel <david.vrabel@citrix.com>
Cc: netdev@vger.kernel.org, konrad.wilk@oracle.com,
	Wei Liu <wei.liu2@citrix.com>,
	ian.campbell@citrix.com, xen-devel@lists.xen.org
Subject: Re: [PATCH net-next 2/3] xen-netback: switch to per-cpu scratch space
Date: Fri, 24 May 2013 13:31:30 +0100	[thread overview]
Message-ID: <20130524123130.GB16745__32114.7044924603$1369398808$gmane$org@zion.uk.xensource.com> (raw)
In-Reply-To: <519F5C09.3030502@citrix.com>

On Fri, May 24, 2013 at 01:24:41PM +0100, David Vrabel wrote:
> On 24/05/13 11:32, Wei Liu wrote:
> > There are maximum nr_onlie_cpus netback threads running. We can make use of
> > per-cpu scratch space to reduce the size of buffer space when we move to 1:1
> > model.
> 
> How much memory does this actually save?  At first glance the savings
> don't seem worth it for the extra complexity wrt hotplugged VCPUs etc.
> 

It would not save any for the old model netback. But if we switch to 1:1
model the saving depends on how many vifs you run.

This can be calculated by:
(nr_vifs - nr_cpus) * sizeof(scratch space)


Wei.

> David

  parent reply	other threads:[~2013-05-24 12:31 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-05-24 10:32 [PATCH net-next 0/3] xen-netback: switch to NAPI + kthread 1:1 model Wei Liu
2013-05-24 10:32 ` [PATCH net-next 1/3] xen-netback: page pool support Wei Liu
2013-05-24 10:32 ` Wei Liu
2013-05-24 12:44   ` David Vrabel
2013-05-24 12:44   ` [Xen-devel] " David Vrabel
2013-05-24 13:25     ` Wei Liu
2013-05-24 13:25     ` Wei Liu
2013-05-24 13:34     ` Wei Liu
2013-05-24 13:34     ` [Xen-devel] " Wei Liu
2013-05-24 10:32 ` [PATCH net-next 2/3] xen-netback: switch to per-cpu scratch space Wei Liu
2013-05-24 10:32 ` Wei Liu
2013-05-24 12:24   ` David Vrabel
2013-05-24 12:24   ` [Xen-devel] " David Vrabel
2013-05-24 12:31     ` Wei Liu
2013-05-24 12:31     ` Wei Liu [this message]
2013-05-24 10:32 ` [PATCH net-next 3/3] xen-netback: switch to NAPI + kthread 1:1 model Wei Liu
2013-05-24 10:32 ` Wei Liu

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