Re: [Xen-devel] xenoprof passive mode overhead

[Dulloor <dulloor@xxxxxxxxx>]

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@xxxxxxxxx> 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
>
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@xxxxxxxxxxxxxxxxxxx
> http://lists.xensource.com/xen-devel
>

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel