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Re: [Xen-devel] How to reduce high latency on PV-on-HVM?

To: "shen.qilong" <shen.qilong@xxxxxxxxxxxx>
Subject: Re: [Xen-devel] How to reduce high latency on PV-on-HVM?
From: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
Date: Wed, 5 Jan 2011 13:47:01 +0000
Cc: xen-devel <xen-devel@xxxxxxxxxxxxxxxxxxx>, 王鹏 <wang.peng@xxxxxxxxxx>
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User-agent: Alpine 2.00 (DEB 1167 2008-08-23)
On Tue, 4 Jan 2011, shen.qilong wrote:
> About ping latency in PV-on-HVM
> I had tried a test to ping between two VM(PV-on-HVM) in the same host server 
> with bridge model.
> I think there would be slightly latency mostly(less than 1ms).
> But I found that there are too much high latency package (more than 1ms) 
> in PV-on-HVM + bridge environment.
> The following is the test environment and the test result:
> Server uses xen-4.0.0, domain-0 is kernel- and PV-on-HVM is kernel-2.6.x. 
> The server and client are connected through a same network bridge. 
> Can someone help me, or tell me something?

If you boot your guest kernel with loglevel=9, can you see the following line
among the boot messages?

Xen HVM callback vector for event delivery is enabled
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