On Mon, Aug 18, 2008 at 10:51 PM, Rafael J. Wysocki <rjw@sisk.pl> wrote:
quoted text
> Apparently nmi_suspend() conflicts with oprofile somehow.  Also, the offlining
> of non-boot CPUs may confuse it.  It would be helpful to check if the CPU
> hotplug works with oprofile.

That is a good suggestion :-)

Here is offlining:

CPU 1 is now offline
lockdep: fixing up alternatives.
SMP alternatives: switching to UP code
CPU0 attaching NULL sched-domain.
WQ on CPU0, prefer CPU1
CPU1 attaching NULL sched-domain.
CPU0 attaching sched-domain:
 domain 0: span 0 level CPU
  groups: 0
WQ on CPU0, prefer CPU1
WQ on CPU0, prefer CPU1
WQ on CPU0, prefer CPU1
[repeat last message indefinitely]

Here is onlining:

Booting processor 1/1 ip 6000
Initializing CPU#1
WQ on CPU0, prefer CPU1
WQ on CPU0, prefer CPU1
Calibrating delay using timer specific routine.. 5986.15 BogoMIPS (lpj=29930790)
CPU: Trace cache: 12K uops, L1 D cache: 16K
CPU: L2 cache: 2048K
CPU: Physical Processor ID: 0
Intel machine check architecture supported.
Intel machine check reporting enabled on CPU#1.
CPU1: Intel P4/Xeon Extended MCE MSRs (24) available
CPU1: Thermal monitoring enabled
x86 PAT enabled: cpu 1, old 0x7040600070406, new 0x7010600070106
CPU1: Intel(R) Pentium(R) 4 CPU 3.00GHz stepping 05
checking TSC synchronization [CPU#0 -> CPU#1]:
Measured 120 cycles TSC warp between CPUs, turning off TSC clock.
Marking TSC unstable due to check_tsc_sync_source failed
APIC error on CPU1: 00(40)
Clockevents: could not switch to one-shot mode:<7>APIC error on CPU1: 40(40)
 lapic is not functional.
Could not switch to high resolution mode on CPU 0
Clockevents: could not switch to one-shot mode: lapic is not functional.
Could not switch to high resolution mode on CPU 1
APIC error on CPU1: 40(40)
[sched domains messages
WQ on CPU0, prefer CPU1
APIC error on CPU1: 40(40)
[repeat last message 9 times]

Then follows this pattern indefinitely:

WQ on CPU0, prefer CPU1
APIC error on CPU1: 40(40)
[repeat last message 9 times]

That's basically the same thing as I saw with suspend. So it can be
reproduced easily with CPU hotplug.


Vegard

-- 
"The animistic metaphor of the bug that maliciously sneaked in while
the programmer was not looking is intellectually dishonest as it
disguises that the error is the programmer's own creation."
	-- E. W. Dijkstra, EWD1036
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