Rafael J. Wysocki wrote:
On Monday, 28 of January 2008, Rafael J. Wysocki wrote:
On Monday, 28 of January 2008, Steven Rostedt wrote:
Rafael J. Wysocki wrote:
No, this isn't the WARN_ON().
this does have the feel of being scheduling related, but are you
absolutely sure about the precise identity of the patch?
Actually, not quite. That's why I have verified it and found that another
patch is really responsible for the issue, namely:
commit 82a1fcb90287052aabfa235e7ffc693ea003fe69
Author: Ingo Molnar <[EMAIL PROTECTED]>
Date: Fri Jan 25 21:08:02 2008 +0100
softlockup: automatically detect hung TASK_UNINTERRUPTIBLE tasks
Are you getting a bunch of prints from the softlockup detector in dmesg?
No, I don't. In fact, I don't get _any_ messages from it whatsoever.
I wonder if the detector can detect a long timeout caused by suspend and
resume and if not is triggering false positives?
I'm not sure, but the code is supposed to be suspend-aware, IIRC. However,
I'm seeing a similar symptom on poweroff on an SMP x86-64 box, so it may be
more directly related to the CPU hotplug. I'll try to verify that.
As I expected, the delay is also observable when I do:
echo 0 > /sys/devices/system/cpu/cpu1/online
(it's variable, between 3 and 30 seconds). Again, no messages appear in dmesg
when this happens.
I suspect I'll be able to reproduce it on another x86-64 SMP machine (I'm going
to try that later today).
Could you download my tracing patches from here:
http://people.redhat.com/srostedt/tracing/mcount-tracing-patches-v6.tar.bz2
Apply the above patches and select all but the histogram tracers. Then
run this program
http://people.redhat.com/srostedt/tracing/trace-cmd.c
./trace-cmd -f echo 0 > /sys/devices/system/cpu/cpu1/online
then do this (mount debugfs):
bzip2 -c /debugfs/tracing/latency_trace > /tmp/trace.bz2
and send the result to myself and Ingo.
Thanks,
-- Steve
Thanks,
Rafael
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