Performance issue - VoIP application on Linux 2.4.22

[Fillod Stephane]

bobys wrote:
>Hello everybody,
>I have a multithreaded VoIP application in user space and a kernel
driver
>module on MPC 8248 based board.
>During media data transfer( Video Call) I have observed one strange
>behavior
>that at specific interval, cpu utilization is reaching to 100 % and
then
>rolls back to 0 %.  This behavior repeats at regular intervals of time
>during the call.
>During this time, data rate and memory utilization is constant
throughout
>the Call. Also number of interrupts received and processed in the
kernel
>driver is constant.  We have checked the code many times, but couldn't
find
>any of the threads/driver hogging the processor time.
>We are using Linux kernel 2.4.22  with kernel preemption enabled and
low
>latency patch added. Please let me know anybody have seen same behavior
and
>how to sort this out.

I have no idea with 2.4.x. However, if you have OProfile[1] support
available in your kernel (look for custom module on 2.4), that's quite
easy 
to spot the cpu utilization burst.

[1] http://oprofile.sf.net


Best Regards
-- 
Stephane

PS: OProfile is a neat tool. We won't thank enough the OProfile team.