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aconverse
Beginner
41 Views

Sampling halts early for some Linux programs

Trying to sample ffmpeg (available from http://www.ffmpeg.org) in VTune 9.1 on Linux seems to halt early. I can callgraph the program file. I can sample the gsexample2a program fine. But when I sample ffmpeg the sampler immediately spins down only harvesting the initialization information.

The console log is:

Thu Mar 12 14:00:22 2009 127.0.0.1 (Run 0) Setting Sampling CPU mask to 0-1
Thu Mar 12 14:00:22 2009 127.0.0.1 (Run 0) The processor PMU configuration file: pmm.xml
Thu Mar 12 14:00:22 2009 127.0.0.1 (Run 0) Collection for the following event(s) is being performed:
Thu Mar 12 14:00:22 2009 127.0.0.1 (Run 0) CPU_CLK_UNHALTED.CORE, INST_RETIRED.ANY.
Thu Mar 12 14:00:23 2009 127.0.0.1 (Run 0) Sampling data was successfully collected.

If I switch to sampling for a fixed amount of time rather than until the program exits it still only gives me the initialization information. In the terminal where I launched vtlec IT shows the ffmpeg startup output but not the ffmpeg progress information that is present when I run the callgraph task.

I built ffmpeg as "ffmpeg_g: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), for GNU/Linux 2.6.8, dynamically linked (uses shared libs), not stripped" with gcc 4.3.2 and yasm.
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1 Reply
David_A_Intel1
Employee
41 Views

Hi aconverse:

How is the app started? Your symptom is typical of a script or app that starts another process and then shuts down. The sampling feature does not track processes, only the original process.

You say that when you specified a duration, it still only captured the initialization. Did you uncheck the option to "Stop collecting data when application terminates?"

Hope that helps!

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