From mboxrd@z Thu Jan  1 00:00:00 1970
From: Suravee Suthikulanit <suravee.suthikulpanit@amd.com>
Subject: Re: Xen 4.3 development update
Date: Tue, 2 Apr 2013 18:48:27 -0500
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To: Tim Deegan <tim@xen.org>
Cc: George Dunlap <George.Dunlap@eu.citrix.com>, Andres Lagar-Cavilla <andres@lagarcavilla.org>, Jan Beulich <JBeulich@suse.com>, "xen-devel@lists.xen.org" <xen-devel@lists.xen.org>
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On 4/2/2013 12:06 PM, Suravee Suthikulpanit wrote:
> On 4/2/2013 11:34 AM, Tim Deegan wrote:
>> At 16:42 +0100 on 02 Apr (1364920927), Jan Beulich wrote:
>>>>>> On 02.04.13 at 16:07, George Dunlap <George.Dunlap@eu.citrix.com> 
>>>>>> wrote:
>>>> * AMD NPT performance regression after c/s 24770:7f79475d3de7
>>>>    owner: ?
>>>>    Reference: http://marc.info/?l=xen-devel&m=135075376805215
>>> This is supposedly fixed with the RTC changes Tim committed the
>>> other day. Suravee, is that correct?
>> This is a separate problem.  IIRC the AMD XP perf issue is caused by the
>> emulation of LAPIC TPR accesses slowing down with Andres's p2m locking
>> patches.  XP doesn't have 'lazy IRQL' or support for CR8, so it takes a
>> _lot_ of vmexits for IRQL reads and writes.
> Is there any tools or good ways to count the number of VMexit in Xen?
>
Tim/Jan,

I have used iperf benchmark to compare network performance (bandwidth) 
between the two versions of the hypervisor:
1. good: 24769:730f6ed72d70
2. bad: 24770:7f79475d3de7

In the "bad" case, I am seeing that the network bandwidth has dropped 
about 13-15%.

However, when I uses the xentrace utility to trace the number of VMEXIT, 
I actually see about 25% more number of VMEXIT in the good case.  This 
is inconsistent with the statement that Tim mentioned above.

Suravee

> Thanks,
> Suravee
>>
>> Tim.
>>
>