oprofile on Linux running in a virtual machine

Question

I'm running a Linux Ubuntu 10.4 VM using VirtualBox. I'm trying to use oprofile to profile some application in the virtual machine. I've installed oprofile 0.9.6 but I cannot get it to work. When I try to start I get the following error:

opcontrol --start
/usr/local/bin/opcontrol: line 323: /usr/local/bin/ophelp: cannot execute binary file
/usr/local/bin/opcontrol: line 1483: /usr/local/bin/oprofiled: cannot execute binary file
Couldn't start oprofiled.
Check the log file "/var/lib/oprofile/samples/oprofiled.log" and kernel syslog

As I'm not sure if VirtualBox could provide access to the performance counters (I'm in doubt here so if you have any pointers it would be great) I defaulted oprofile to the timer interrupt like so:

opcontrol --deinit
/usr/local/bin/opcontrol: line 323: /usr/local/bin/ophelp: cannot execute binary file
Unloading oprofile module
root@dev-ubuntu-10:/usr/local/bin# /sbin/modprobe oprofile timer=1
root@dev-ubuntu-10:/usr/local/bin# opcontrol --init

But still not working and I'm getting the same error. Is it even possible to run oprofile in a VM?

Thanks

Answer 1

I've tried something similar in the past, only with VMware Fusion and a different profiler, and run into the same problem. It seems that access to the performance registers and other low level stuff that profilers need is just not feasible in a VM. You'll need a real machine for profiling, I'm afraid.

Answer 2

This error:

/usr/local/bin/ophelp: cannot execute binary file

usually means that you are attempting to execute an x86_64 binary on a 32-bit kernel.

What do file usr/local/bin/ophelp and uname -a print?