WARNING - OLD ARCHIVES

This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
   
 
 
Xen 
 
Home Products Support Community News
 
   
 

xen-devel

[Xen-devel] Re: some performance issue of shadow2 on 2.6 Linux VMX and p

To: "Yang, Xiaowei" <xiaowei.yang@xxxxxxxxx>
Subject: [Xen-devel] Re: some performance issue of shadow2 on 2.6 Linux VMX and possible fix
From: Tim Deegan <Tim.Deegan@xxxxxxxxxxxxx>
Date: Thu, 23 Nov 2006 18:07:15 +0000
Cc: xen-devel@xxxxxxxxxxxxxxxxxxx, "Nakajima, Jun" <jun.nakajima@xxxxxxxxx>
Delivery-date: Thu, 23 Nov 2006 10:07:28 -0800
Envelope-to: www-data@xxxxxxxxxxxxxxxxxx
In-reply-to: <8C834404208B254EAD4E532C94859869056BEF@xxxxxxxxxxxxxxxxxxxxxxxxxxxx>
List-help: <mailto:xen-devel-request@lists.xensource.com?subject=help>
List-id: Xen developer discussion <xen-devel.lists.xensource.com>
List-post: <mailto:xen-devel@lists.xensource.com>
List-subscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=unsubscribe>
References: <8C834404208B254EAD4E532C94859869056BEF@xxxxxxxxxxxxxxxxxxxxxxxxxxxx>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
User-agent: Mutt/1.5.13 (2006-08-11)
Hi, 

At 17:13 +0800 on 23 Nov (1164301986), Yang, Xiaowei wrote:
> On ia32e system, old Linux 2.6 kernel (previous to 2.6.16) shares one l4
> page for all processes. At context switch, it replaces old L3 page in
> l4e with the new one. Current shadow discards old shadow page at the
> same time. When context switch (e.g. client/server model) is very
> frequent, it can be a high cost.
> 
> One solution is to pin L3 page as well as L4 page. It reserves previous
> process' L3 shadow page for later use. The test shows it benefits
> benchmark with frequent context switch such as OLTP (server/client),
> CPU2k (multi users) and specjbb (multi warehouses). 

Thanks!  Changeset 12533:2fd223c64fc6 pins l3 shadows, and falls back to
normal behaviour if we see the guest using too many l4 pages.

Cheers,

Tim.

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel

<Prev in Thread] Current Thread [Next in Thread>