Re: profiling active RHEL 4 PV domains with xenoprof

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

Big thanks to Renato and George -- I now have OProfile working for
active PV domains. The key was that my guest kernel didn't have the
xenoprof patches. I built the 2.6.18-xenU kernel/modules from
xen-unstable and pushed those to my domU. I had to `make menuconfig` to
set CONFIG_PROFILING=y and CONFIG_OPROFILE=m after doing the `make
KERNELS=linux-2.6-xenU kernels` from the top of my xen-unstable.hg tree.
I also had to mkinitrd again to create a ramdisk compatible with the new
kernel.

Now `opreport -l` in dom0 shows output like this:

CPU: Core 2, speed 2500.01 MHz (estimated)
Counted CPU_CLK_UNHALTED events (Clock cycles when not halted) with a
unit mask of 0x00 (Unhalted core cycles) count 1000000
samples  %        app name                 symbol name
219      12.1734  vmlinux-unknown          (no symbols)
158       8.7827  e1000e                   (no symbols)
115       6.3924  vmlinux                  .text.read_sb_page
94        5.2251  xen-unknown              (no symbols)
72        4.0022  libpython2.4.so.1.0      (no symbols)
49        2.7237  vmlinux                  xfrm_state_find
44        2.4458  vmlinux                  .text.md_ioctl
37        2.0567  bridge                   (no symbols)
34        1.8899  netbk                    (no symbols)

I'm running a different kernel in the domU to the one in my dom0, and it
doesn't appear to be possible to pass multiple vmlinux paths to
opcontrol. Renato's
http://www.xen.org/files/summit_3/xenoprof_tutorial.pdf uses the same
kernel in dom0 and domU. Is that a requirement, or is there a way for me
to point oprofiled or opreport to my guest kernel's debug symbols too?

thanks,

-Andrew