If you use a very low threshold for triggering events, the overhead
would be more. Looks like thats the case with you.
-dulloor
On Thu, Mar 25, 2010 at 2:06 PM, Ya-Yunn Su <yayunn.su@gmail.com>
wrote:> Hi all,
> I''d like to use xenoprof passive mode on domain-0 to calculate L2
> cache missed for each guest domain. I setup oprofile daemon as
> followed
>
> opcontrol --start-daemon --event=LLC_MISSES:4000
> --xen=/boot/xen-3.4.2.gz
> --vmlinux=/scratch/xen-3.4.2/build-linux-2.6.18-lttng-xen0_x86_32/vmlinux
> --passive-domains=1,2
>
--passive-images=/scratch/xen-3.4.0/build-linux-2.6.18-xenU_x86_32/vmlinux,/scratch/xen-3.4.0/build-linux-2.6.18-xenU_x86_32/vmlinux
>
> My machine has two cores and I pinned domain-0 to one core and guest
> domains to the other. When I ran oprofile to calculate cache
> misses/sec every 5 seconds on domain 0, I noticed that the transient
> CPU utilization can be as high as 30%. This affects the performance
> of whatever benchmark I''m running in the guest domain. Is this
30%
> overhead for domain-0 common or am I doing something obviously wrong?
> Any suggestion is appreciated.
>
> Thank you,
> Ya-Yunn
>
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