Messages in this thread | | | Date | Fri, 03 Dec 2004 15:58:36 -0600 | From | Chris Friesen <> | Subject | looking for help, attempting to debug high latency in 2.4 kernel |
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Hi guys,
I'm running 2.4.22 on ppc32. Embedded system, just 74xx cpu, dual tulip network links and fiberchannel card. Card has 1.5GB of memory, rootfs is tmpfs, system has some NFS mounts.
We're seeing userspace delayed for almost a second every so often. No idea what's causing it.
We've got scheduler instrumentation showing a usespace task starting to run, then a bunch of tasks being put on the runqueue, and finally we wake up and start running normally again almost a full second later. The timing is not exactly the same in each case, but it's usually close to a second of delay.
I'm looking for some tips on how to go about tracking this down.
Where are my delays likely to be coming from? Long-running code paths? Long periods with interrupts off? I dunno where to start.
Would porting lockmeter be a good idea? Is there anyone who's already done this for ppc?
I appreciate any help.
Thanks,
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