Re: Problem using oprofpp

[Philippe E. <ph...@wa...>]

clo...@ma... wrote:
> Dear Philippe,
> 
> Thanks your advice.. 
> but I still can't get the samples file..
> I am using rtc counter and I decrease it even to 2 using the following command...
> 
> op_start --vmlinux=/boot/vmlinux-2.4.18-19.8.0smp --rtc-value=2
> then op_dump
> and then op_time to get the following

oh right, I though you used hardware performance counter. For
rtc based sampling you must increase --rtc-value=xxxx to increase
sample rate. Try high value like --rtc-value=4096 and run your
program a few times (if you run your application more than one time
during a profiling session samples will be cumulated).

> 
> 1          8.3333 0.0000 /lib/i686/libc-2.2.93.so
> 1          8.3333 0.0000 /usr/X11R6/lib/libX11.so.6.2
> 10        83.3333 0.0000 /boot/vmlinux-2.4.18-19.8.0smp
> 
> I would liek to know what would be supposed to get after op_time if I am in a correct path?

You should see something like:

  1          8.3333 0.0000 /lib/i686/libc-2.2.93.so
  1          8.3333 0.0000 /usr/X11R6/lib/libX11.so.6.2
  10        83.3333 0.0000 /boot/vmlinux-2.4.18-19.8.0smp
  xxx       zzzzzzz 0.0000 /my/path/to/my/application

If your application doesn't appear with op_time, it means
than your application didn't receive any samples and so
on oprofopp will fail. During profling how many time your
application runs ?

> Then I use oprofpp -l /path/to/application to the application I use.
> 
> also after op_start, it prints and says ...
> Backing up samples file to directory /var/lib/oprofile/samples//session-5
> What's that mean? should I find the samples files here or the place where my execution file located?

this means than daemon detect you change profiling parameters
between two profiling session, old profiling samples files are
backed up in directory session named sssion-xxxx. The samples
file for the last (or current session) are always in
/var/lib/oprofile/samples

regards,
Phil