Re: [patch 1/4] Ignore stolen time in the softlockup watchdog

From: Andrew Morton
Date: Tue Apr 24 2007 - 14:34:31 EST


On Tue, 24 Apr 2007 11:16:09 -0700 Jeremy Fitzhardinge <jeremy@xxxxxxxx> wrote:

> Andrew Morton wrote:
> > I said that because the damn thing went away when I was hunting it down
> > because I lost the config and was unable to remember the right combination
> > of debug settings. Fortunately it later came back so I took care to
> > preserve the config.
> >
>
> sched_clock doesn't *do* anything except flap interrupts.

Well, it _is_ mysterious.

Did you try to locate the code which failed? I got lost in macros and
include files, and gave up very very easily. Stop hiding, Ingo.

> Oh, wait, have
> you got Andi's bugfixed version of the sched_clock patch? The first
> version did a local_save_flags rather than a local_irq_save.

I have whatever I pulled from firstfloor over the weekend. It's in
rc7-mm1. No, it doesn't use local_save_flags.

> >> Hm, is it caused by using sched_clock() to generate the printk
> >> timestamps while generating the lock test output?
> >>
> >
> > Conceivably. What does that locking API test do?
> >
>
> Didn't make a difference here. Building your config now.
>
> > I was using printk timestamps and netconsole at the time.
> >
>
> Ah, great, now you're going to make me setup netconsole...
>

That's a doddle.

On test system, boot with

netconsole=4444@<test-system-ip-addr>/eth0,<udp-port-no>@<workstation-ip-addr>/<workstation-mac-addr>

On workstation:

sudo netcat -u -l -p <udp-port-no> | tee -a ~/.log/log-<test-system-hostname>
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