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To: Perry Cheng <perryche@us.ibm.com>
Cc: systemtap@sourceware.org
Subject: Re: Instrumenting context switches
References: <OFD87C37F9.05443A89-ON85257235.0080AA5F-85257235.0080B921@us.ibm.com>
From: fche@redhat.com (Frank Ch. Eigler)
Date: Thu, 30 Nov 2006 01:41:00 -0000
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> [...]
>         doSwitchTo(gettimeofday_us(), $prev_p, $next_p);
> [...]

It may be that this problem is due to the recent rewrite of
gettimeofday_us.  That code contains bits like preempt_disable() and
_enable(), even though the equivalent (interrupt disabling) should
already be done within probe context.  In particular, I wonder if
changing the latter to preempt_enable_no_resched() might improve the
situation.

- FChE