Question about running a program(Intel PCM) in ring 0 on Xen

[Meng Xu <xumengpanda@gmail.com>]

[-- Attachment #1.1: Type: text/plain, Size: 1578 bytes --]

Hi,

I'm a PhD student, working on real time system.

*[My goal]*
I want to measure the cache hit/miss rate of each guest domain in Xen. I
may also want to measure some other events, say memory access rate, for
each program in each guest domain in Xen.

My machine's CPU uses intel IvyBridge architecture.

*[The problem I'm encountering]*
I tried intel's Performance Counter Monitor (PCM) in Linux on bare machine
to get the machine's cache access rate for each level of cache, it works
very well.

However, when I want to use the PCM in Xen and run it in dom0, it cannot
work. I think the PCM needs to run in ring 0 to read/write the MSR. Because
dom0 is running in ring 1, so PCM running in dom0 cannot work.

*So my question is:*
How can I run a program (say PCM) in ring 0 on Xen?

*What's in my mind is:*
Writing a hypercall to call the PCM in Xen's kernel space, then the PCM
will run in ring 0?
But the problem I'm concerned is that some of the PCM's instruction, say
printf(), may not be able to run in kernel space?

Do you have any suggestion on running PCM or other performance monitor
program in ring 0 on Xen?

*What I tried before:*
I wrote a hypercall to read and write the MSR and record the cache
hit/miss event for each level of cache, using Intel's performance counter.
It worked on my machine. But it's not portable to other machines since the
event number may be different. That's why I think running PCM or other
existing performance monitor program on Xen will be a better idea.

Thank you very much for your time and help in this question!

Best,

Meng

[-- Attachment #1.2: Type: text/html, Size: 3576 bytes --]

[-- Attachment #2: Type: text/plain, Size: 126 bytes --]

_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel