perf_counter, x86: rework pmc_amd_save_disable_all() and pmc_amd_restore_all()

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MSR reads and writes are expensive. This patch adds checks to avoid
its usage where possible.

[ Impact: micro-optimization on AMD CPUs ]

Signed-off-by: Robert Richter <robert.richter@amd.com>
Cc: Paul Mackerras <paulus@samba.org>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1241002046-8832-5-git-send-email-robert.richter@amd.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

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Robert Richter 2009-04-29 12:47:01 +02:00 • committed by Ingo Molnar

parent 4138960a92

commit 4295ee6266

1 changed files with 14 additions and 10 deletions

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arch/x86/kernel/cpu/perf_counter.c

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