Date: Thu, 10 Jun 2004 10:11:39 -0400 From: Don Bowman <don@sandvine.com> To: 'Bruce Evans' <bde@zeta.org.au>, Don Bowman <don@sandvine.com> Cc: "'current@freebsd.org'" <current@FreeBSD.org> Subject: RE: kernel trap 19 with interrupts disabled Message-ID: <FE045D4D9F7AED4CBFF1B3B813C85337051D8F5C@mail.sandvine.com>
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From: Bruce Evans [mailto:bde@zeta.org.au]
> ... NMI, output but no debugger, hang, patch to workaround ...
I have applied the patch, and will await the next hang.
Out of curiousity, why not use something like this, so the
timeout is fixed in time, rather than a #? I used the tsc here.
static int
my_stop_cpus(u_int map)
{
unsigned long long end_ts = rdtsc() +
1ULL * tsc_freq;
/* send the Xcpustop IPI to all CPUs in map */
selected_apic_ipi(map, XCPUSTOP_OFFSET, APIC_DELMODE_FIXED);
while ((stopped_cpus & map) != map)
{
/* Wait 1 second */
if ( rdtsc() > end_ts )
return 0;
}
return 1;
}
Has anyone else been observing system hangs with
SMP Xeon (P4-based Xeon)? I have been observing this
for more than a year with 4.7. We came up with a workaround
by having a periodic NMI from the perfmon registers,
and having it check for hardclock still incrementing.
The problem we found is that hardclock would stop.
I was hoping it was a race condition in the stable
kernel, but now that i see what is most likely the
same issue on current, i'm starting to wonder. I have
a dual p3 system which has never experienced this problem.
--don
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