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author | Ingo Molnar <mingo@elte.hu> | 2009-08-11 10:40:08 +0200 |
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committer | Ingo Molnar <mingo@elte.hu> | 2009-08-12 14:12:49 +0200 |
commit | 04da8a43da804723a550f00dd158fd5b5e25ae35 (patch) | |
tree | 002fa5e83efaa745b7eaddd329c2aa9d79d2d2f6 /arch/x86/Kconfig | |
parent | 0a5ac84650fb7a7f226814103d95724e34b012ae (diff) | |
download | op-kernel-dev-04da8a43da804723a550f00dd158fd5b5e25ae35.zip op-kernel-dev-04da8a43da804723a550f00dd158fd5b5e25ae35.tar.gz |
perf_counter, x86: Fix/improve apic fallback
Johannes Stezenbach reported that his Pentium-M based
laptop does not have the local APIC enabled by default,
and hence perfcounters do not get initialized.
Add a fallback for this case: allow non-sampled counters
and return with an error on sampled counters. This allows
'perf stat' to work out of box - and allows 'perf top'
and 'perf record' to fall back on a hrtimer based sampling
method.
( Passing 'lapic' on the boot line will allow hardware
sampling to occur - but if the APIC is disabled
permanently by the hardware then this fallback still
allows more systems to use perfcounters. )
Also decouple perfcounter support from X86_LOCAL_APIC.
-v2: fix typo breaking counters on all other systems ...
Reported-by: Johannes Stezenbach <js@sig21.net>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch/x86/Kconfig')
-rw-r--r-- | arch/x86/Kconfig | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 738bdc6..13ffa5d 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -24,6 +24,7 @@ config X86 select HAVE_UNSTABLE_SCHED_CLOCK select HAVE_IDE select HAVE_OPROFILE + select HAVE_PERF_COUNTERS if (!M386 && !M486) select HAVE_IOREMAP_PROT select HAVE_KPROBES select ARCH_WANT_OPTIONAL_GPIOLIB @@ -742,7 +743,6 @@ config X86_UP_IOAPIC config X86_LOCAL_APIC def_bool y depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC - select HAVE_PERF_COUNTERS if (!M386 && !M486) config X86_IO_APIC def_bool y |