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RE: [Xen-devel] Xenoprofile in DomU!

Xenoprofile can only be run from dom0.
Profiling from domU would require virtualizing the performance counters which are not available in Xen today.
You can profile a domU from dom0 using two models: active or passive mode.
I strongly recommend that you use passive mode if you can, since it is much easier to configure and use
The main limitation of passive domain profiling is that you cannot separate application samples, although it still provide you detailed samples for kernel and hypervisor samples. The user level samples are all groupped into a single bin. If you really want a detailed profile of your user level code then you need to use active mode. The tutorial explains how to do that.
 
In any case you have to start Oprofile from dom0 and specify which domains you want to profile.
 
The steps a and b that you mention are just needed if you are usin active mode. In this mode you need to have the uncompressed kernel and xen images available in the domU (e.g. vmlinux-syms-2.6.8.18-xenU, xen-syms-3.4-unstable).
 
Regards
 
Renato

From: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx [mailto:xen-devel-bounces@xxxxxxxxxxxxxxxxxxx] On Behalf Of Ata Bohra
Sent: Sunday, July 12, 2009 3:28 PM
To: xen-users-bounces@xxxxxxxxxxxxxxxxxxx; Xen developer
Subject: [Xen-devel] Xenoprofile in DomU!

Dear All,
 
I am trying to run Xenoprofile in DomU domain. I have been able to get the xenoprofile working for Dom0 but havent got luck yet to make it work for domU(s). I am working on AMD Opetron 64 bit processor with Xen3.4 on rhel5.2 kernel. I am facing following difficulties:
 
1. I am using the images from jailtime.org, have tried ubuntu-8 and centos5.2 images. Ubuntu works fine but centos starts as a readonly filesystem. I tried to mount it as r/w but it didnt worked. I have also tried to create a clone domU by copying files and folders from dom0 kernel (rhel5.2), but it gives me kernel panic when booting up, for this exercise I followed the step from webpage http://www.virtuatopia.com/index.php/Building_a_Xen_Virtual_Guest_Filesystem_on_a_Disk_Image_%28Cloning_Host_System%29.
 
2. I am not able to comprehend fully, these two steps given in Xenoprofile tutorial (http://www.xen.org/files/summit_3/xenoprof_tutorial.pdf):

a. Copy Xen and kernel images (in /boot) to domU file system.

b. Copy domU modules (in /lib/modules) to domU file system
 
Please help me if someone has any suggestion regarding above mentioned points.
 
Thanks!
Ata

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