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authorIngo Molnar <mingo@elte.hu>2011-04-27 11:51:41 +0200
committerIngo Molnar <mingo@elte.hu>2011-04-26 19:34:34 +0200
commitec75a71634dabe439db91c1ef51d5099f4493808 (patch)
treebf62d417bd365f62d4a8afca02a93d37a106a339 /kernel/sched_clock.c
parentperf, x86: Fix BTS condition (diff)
downloadlinux-ec75a71634dabe439db91c1ef51d5099f4493808.tar.xz
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perf events, x86: Work around the Nehalem AAJ80 erratum
On Nehalem CPUs the retired branch-misses event can be completely bogus, when there are no branch-misses occuring. When there are a lot of branch misses then the count is pretty accurate. Still, this leaves us with an event that over-counts a lot. Detect this erratum and work it around by using BR_MISP_EXEC.ANY events. These will also count speculated branches but still it's a lot more precise in practice than the architectural event. Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Link: http://lkml.kernel.org/n/tip-yyfg0bxo9jsqxd6a0ovfny27@git.kernel.org Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/sched_clock.c')
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