Messages in this thread | | | Date | Tue, 23 Nov 2010 22:18:01 +0300 | From | Cyrill Gorcunov <> | Subject | Re: [PATCH] x86, perf, nmi: Disable perf if counters are not accessable |
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On Tue, Nov 23, 2010 at 08:07:47PM +0100, Peter Zijlstra wrote: > On Tue, 2010-11-23 at 22:04 +0300, Cyrill Gorcunov wrote: > > On Tue, Nov 23, 2010 at 07:27:07PM +0100, Peter Zijlstra wrote: > > > On Tue, 2010-11-23 at 19:21 +0100, Sedat Dilek wrote: > > > > Due to BIOS l(ocal)apic is not possible: > > > > > > > > # dmesg | grep -i apic > > > > [ 0.000000] Using APIC driver default > > > > [ 0.000000] Local APIC disabled by BIOS -- you can enable it with "lapic" > > > > [ 0.000000] APIC: disable apic facility > > > > [ 0.000000] APIC: switched to apic NOOP > > > > [ 0.008891] no APIC, boot with the "lapic" boot parameter to force-enable it. > > > > [ 0.036141] Local APIC not detected. Using dummy APIC emulation. > > > > > > Have you tried booting with "lapic" as the second last msg suggests you > > > do? > > > > Peter, Don, might not we need something like the patch below -- ie to check for > > apic earlier and do not acquire cpu for PERF cpu bit, and its cpu model, etc > > if there is no active apic? And perhaps for nmi-watchdog, we should not try > > to creat perf event for same reason and simply report that nmi-watchdog is > > disabled (though of course hpet based one should try to continue). > > > > No? > > > > Ah, no.. now I get what you mean. > > We can use the pmu without interrupt with we miss the lapic, that is > perf-stat will still work. >
Yeah, I forgot about perf-stat
Cyrill
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