Re: [Regression] 2.6.24-git3: Major annoyance during suspend/hibernationon x86-64 (bisected)

[Steven Rostedt]

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 <mingo@xxxxxxx>
> > > > 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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