profiling active RHEL 4 PV domains with xenoprof

[Andrew Evans <andrewe@yahoo-inc.com>]

Hi,

Is it necessary to run a xenoprof-patched oprofile in a PV domU being
actively profiled? I ask because

http://xenoprof.sourceforge.net/xenoprof_2.0.txt

seems to say no (no mention of --xen switch) but

http://www.xen.org/files/summit_3/xenoprof_tutorial.pdf

seems to say yes (specifies use of --xen in domUs). I'm running RHEL 4
in the domU I want to actively profile, and RHEL 4 provides the ancient
oprofile-0.8.1 package, with no support for the --xen switch. I've
gotten oprofile 0.9.6 with xenoprof patches built on RHEL 4 but haven't
been able to test it due to XENOPROF_start failing (see other message).

Another thing I'm confused about: the above xenoprof tutorial also
specifies use of the --event switch in domUs, saying they must use the
same event as dom0. Makes sense, but my domUs are PV, and oprofile says
only timer interrupts are usable. So must I also use timer interrupts on
dom0?

thanks,

-Andrew