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Cpu consumption reduced to 100% during capture

duanetiemann
Beginner
130 Views
Using update 4 on Linux, I notice that our cpu consumption which is otherwise 300%-400% is reduced to 100% during capture. This occurred all both times I tried it.

Is this normal? It seems odd.

Capture interval was 50ms for 2 minutes, if that matters.

The cpu consumption was captured via a ps every 10 seconds.

Duane
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2 Replies
Kirill_R_Intel
Employee
130 Views
Hi Duane,

This looks strange. Could you please provide some additional info about your setup:
- Amplifier XE command line
- Do you runyour app from Amplifier or attach to it? If attaching - does the CPU time comes back to 300%-400% when analysis is complete?
- ps command line you use
- Platform info: OS and CPU type.

I'll try to see if this behavior is reproducible in my lab.
duanetiemann
Beginner
130 Views
Thanks.

Our app is an IONIX server. It does network diagnostics. It was doing a discovery of a simulated network. There were probably around a dozen threads active. But about 100in all. The active stacks were probably 40-80 frames deep, depending.
VTune is installed in my home directory on nfs.


This was done through the GUI. The command line was just "./amplxe-gui".
I attached to the process. CPU consumption does go back up to 300%-400% after the capture.

"ps -eo pid,ppid,stime,pri,time,rss,vsz,nlwp,comm,args | grep sm_server >>outputFile"
This is part of a Perl script. It does it every 10 seconds.
I also ran a script that captured cpu by thread. "ps -L -p >>outputFile". I didn't see any one thread stand out during the measurement period.

Red Hat Enterprise Linux Server release 5.2 (Tikanga)
Kernel 2.6.18-92.1.13.el5 on an x86_64
Intel Xeon CPU X7350 @ 2.93GHz
4 quad cores.

Duane

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