Messages in this thread | | | Date | Tue, 23 Nov 2010 19:37:21 +0100 | Subject | Re: [PATCH] x86, perf, nmi: Disable perf if counters are not accessable | From | Sedat Dilek <> |
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On Tue, Nov 23, 2010 at 7:29 PM, Sedat Dilek <sedat.dilek@googlemail.com> wrote: > On Tue, Nov 23, 2010 at 7:27 PM, Peter Zijlstra <peterz@infradead.org> 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? >> > > Yes, I did try before there was [1], booting with "lapic" had no effect. > > - Sedat - > > [1] bugfix/x86/Skip-looking-for-ioapic-overrides-when-ioapics-are-not-present.patch >
OK, some months went by when I last tested this option.
Now, with linux-next (next-20101123) things look better.
# cat /proc/cmdline BOOT_IMAGE=/boot/vmlinuz-2.6.37-rc3-686 root=UUID=1ceb69a7-ecf4-47e9-a231-b74e0f0a9b62 ro radeon.modeset=1 lapic 3
# dmesg | egrep -i 'NMI|APIC' [ 0.000000] Using APIC driver default [ 0.000000] Local APIC disabled by BIOS -- reenabling. [ 0.000000] Found and enabled local APIC! [ 0.000000] Kernel command line: BOOT_IMAGE=/boot/vmlinuz-2.6.37-rc3-686 root=UUID=1ceb69a7-ecf4-47e9-a231-b74e0f0a9b62 ro radeon.modeset=1 lapic 3 [ 0.032158] Enabling APIC mode: Flat. Using 0 I/O APICs [ 0.036000] NMI watchdog enabled, takes one hw-pmu counter.
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