Re: [Xen-devel] xenoprofile and multiplexing of events (AMD patch)

[Muhammad Atif <m_atif_s@xxxxxxxxx>]

Thanks for the info. Unfortunatly  I am one of the people who desperately want to have multiplexing of hardware events in Xen. We are working on HPC applications on Xen so lack of  patches like perfctl/perfmon is quite annoying. :)

I will read the xenoprofile paper and related documents before asking more questions on implementing such a facility. But one quick question (may be a naive one) is where to look into the code if I want to give hardware performance counters to only dom0. I don't want fancy stuff (like per process/function etc)... just purely read the counter values of each of the CPU.

 

Best Regards,
Muhammad Atif

----- Original Message ----
From: "Santos, Jose Renato G" <joserenato.santos@xxxxxx>
To: "Santos, Jose Renato G" <joserenato.santos@xxxxxx>; Muhammad Atif <m_atif_s@xxxxxxxxx>; Viren Kumar <virenk@xxxxxxx>; "xen-devel@xxxxxxxxxxxxxxxxxxx" <xen-devel@xxxxxxxxxxxxxxxxxxx>
Sent: Tuesday, June 17, 2008 1:25:58 PM
Subject: RE: [Xen-devel] xenoprofile and multiplexing of events (AMD patch)

Muhammad,

 

Thanks for sharing the patch. The patch seems to reprogram event counters in regular intervals to profile different events with the same counters. Unfortunately this will not work on Xen unless someone writes a patch. Not sure if it is worth the effort though. I am not sure how frequently people want to profile more events than available, although I can see it could be useful in a few cases.

 

Renato   

---

From: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx [mailto:xen-devel-bounces@xxxxxxxxxxxxxxxxxxx] On Behalf Of Santos, Jose Renato G
Sent: Friday, June 13, 2008 4:51 PM
To: Muhammad Atif; Viren Kumar; xen-devel@xxxxxxxxxxxxxxxxxxx
Subject: RE: [Xen-devel] xenoprofile and multiplexing of events (AMD patch)

Muhammad,

 

I am not familiar with this AMD patch. Is this a linux kernel patch? If you can provide more details of what the patch does, perhaps I can comment on the implications of its use with Xen.

 

Regards

 

Renato

---

From: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx [mailto:xen-devel-bounces@xxxxxxxxxxxxxxxxxxx] On Behalf Of Muhammad Atif
Sent: Thursday, June 12, 2008 6:50 AM
To: Muhammad Atif; Viren Kumar; xen-devel@xxxxxxxxxxxxxxxxxxx
Subject: [Xen-devel] xenoprofile and multiplexing of events (AMD patch)

Hi developers! especially xenoprofile gurus

Jason Yeh of AMD has just released a patch for multiplexing hardware events in oprofile for AMDs.  Has anybody looked into that with Xen's perspective? Is it trivial to be hooked on to our xen kernels?
Second question, is there any way we can get access of hardware performance counters even in a very raw form i.e. only available to dom0 (even if it is still a specialized domu).
Best Regards,
Muhammad Atif

----- Original Message ----
From: Muhammad Atif <m_atif_s@xxxxxxxxx>
To: Viren Kumar <virenk@xxxxxxx>; xen-devel@xxxxxxxxxxxxxxxxxxx
Sent: Thursday, June 12, 2008 11:34:52 PM
Subject: Re: [Xen-devel] Status of hardware performance counters in Xen

AFAIK nope.
I am also looking for a nice way to get hold of performance counters in Xen, but seems like its not making on to top of priority queue, perhaps one of us should try it or we can collaborate. :)
So, still the way to go is oprofile (xenoprofile).

 

Best Regards,
Muhammad Atif

----- Original Message ----
From: Viren Kumar <virenk@xxxxxxx>
To: xen-devel@xxxxxxxxxxxxxxxxxxx
Sent: Wednesday, June 11, 2008 9:41:42 AM
Subject: [Xen-devel] Status of hardware performance counters in Xen

Hello everyone,

I'm wondering what the current status of hardware performance counter
usability in Xen is. I see some old posts describing the diffculties of
virtualizing hardware counters within dom0 and the domUs, but not much else.

Have they been implemented or are they in the process of being implemented? Or
are there no future plans for implementation? Any help would be appreciated.

My platform would be Xen with Solaris x86 as the dom0 (xVM) and Solaris or
Linux as the domUs.

Thanks,
Viren


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