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: "monitor"-ed address and IPI reduction

To: Jan Beulich <JBeulich@xxxxxxxxxx>
Subject: [Xen-devel] RE: "monitor"-ed address and IPI reduction
From: "Wei, Gang" <gang.wei@xxxxxxxxx>
Date: Tue, 9 Mar 2010 16:39:13 +0800
Accept-language: zh-CN, en-US
Acceptlanguage: zh-CN, en-US
Cc: "xen-devel@xxxxxxxxxxxxxxxxxxx" <xen-devel@xxxxxxxxxxxxxxxxxxx>
Delivery-date: Tue, 09 Mar 2010 00:40:05 -0800
Envelope-to: www-data@xxxxxxxxxxxxxxxxxxx
In-reply-to: <4B9610140200007800033694@xxxxxxxxxxxxxxxxxx>
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/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=unsubscribe>
References: <4B9610140200007800033694@xxxxxxxxxxxxxxxxxx>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
Thread-index: Acq/X7uzHWoNX1poSRqUbcD+XJl8LAAAcPDw
Thread-topic: "monitor"-ed address and IPI reduction
Jan Beulich wrote:
> What is the point of specifying "current" as the address to monitor?

You provide a good point. The original purpose to monitor "current" is to avoid 
accidentally wakeup while relying on ipi for waking up mechanism.

> The memory location of interest really is
> irq_stat[cpu].__softirq_pending, and if that was used it would then
> also be possible to actually avoid sending IPIs when monitor/mwait
> are in use, as is being done on Linux. 

I agree that we can have a try on this. Waking up cpu by mem write should be 
more efficient for monitor/mwait case.

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