Performance issue - VoIP application on Linux 2.4.22

Performance issue - VoIP application on Linux 2.4.22

[bobys]

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.
Thanks and Regards
Boby

RE: 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=20
to spot the cpu utilization burst.

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


Best Regards
--=20
Stephane

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