Re: [Xen-devel] profiling active RHEL 4 PV domains with xenoprof

[Dulloor <dulloor@xxxxxxxxx>]

I didn't test active profiling much, because I was interested in
profiling only the guest kernel. It could be the patches. I will take
a look and get back.

-dulloor

On Fri, Jan 29, 2010 at 12:04 PM, Santos, Jose Renato G
<joserenato.santos@xxxxxx> wrote:
>
>
>> -----Original Message-----
>> From: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
>> [mailto:xen-devel-bounces@xxxxxxxxxxxxxxxxxxx] On Behalf Of
>> Andrew Evans
>> Sent: Thursday, January 28, 2010 5:38 PM
>> To: xen-devel@xxxxxxxxxxxxxxxxxxx
>> Subject: [Xen-devel] profiling active RHEL 4 PV domains with xenoprof
>>
>> Hi,
>>
>> Is it necessary to run a xenoprof-patched oprofile in a PV
>> domU being actively profiled? I ask because
>
>   Yes, you need need xenoprof support both in the kernel and in the OProfile 
> user level tools in anctive profiled domain.
>>
>> http://xenoprof.sourceforge.net/xenoprof_2.0.txt
>>
>> seems to say no (no mention of --xen switch) but
>>
>> http://www.xen.org/files/summit_3/xenoprof_tutorial.pdf
>>
>> seems to say yes (specifies use of --xen in domUs). I'm
>> running RHEL 4 in the domU I want to actively profile, and
>> RHEL 4 provides the ancient
>> oprofile-0.8.1 package, with no support for the --xen switch.
>> I've gotten oprofile 0.9.6 with xenoprof patches built on
>
>
>  Are you sure Oprofile user level tools has xenoprof support?
>  The latest patch avaialable in http://xenoprof.sourceforge.net/ is for 
> oprofile 0.9.5 but you claim to be using 0.9.6
>  Try using 0.9.5 and apply the patch.
>
>> RHEL 4 but haven't been able to test it due to XENOPROF_start
>> failing (see other message).
>>
>
>> Another thing I'm confused about: the above xenoprof tutorial
>> also specifies use of the --event switch in domUs, saying
>> they must use the same event as dom0. Makes sense, but my
>> domUs are PV, and oprofile says only timer interrupts are
>> usable. So must I also use timer interrupts on dom0?
>>
>
>  No, you should use the same event in dom0 and domU and not timer mode.
>  If Oprofile is reporting timer mode in domU there is something wrong in its 
> OProfile configuration; either you don't have the right patches or you are 
> not correctly synchronyzing dom0 and domU opcontrol commands.
>
>
>  Renato
>
>> thanks,
>>
>> -Andrew
>>
>>
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>>
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