Commit-ID: f92b7604149a55cb601fc0b52911b1e11f0f2514 Gitweb: http://git.kernel.org/tip/f92b7604149a55cb601fc0b52911b1e11f0f2514 Author: Imre Palik <[email protected]> AuthorDate: Fri, 21 Oct 2016 01:18:59 -0700 Committer: Ingo Molnar <[email protected]> CommitDate: Fri, 28 Oct 2016 11:06:25 +0200
perf/x86/intel: Honour the CPUID for number of fixed counters in hypervisors perf doesn't seem to honour the number of fixed counters specified by CPUID leaf 0xa. It always assumes that Intel CPUs have at least 3 fixed counters. So if some of the fixed counters are masked out by the hypervisor, it still tries to check/set them. This patch makes perf behave nicer when the kernel is running under a hypervisor that doesn't expose all the counters. This patch contains some ideas from Matt Wilson. Signed-off-by: Imre Palik <[email protected]> Signed-off-by: Peter Zijlstra (Intel) <[email protected]> Reviewed-by: Andi Kleen <[email protected]> Cc: Alexander Kozyrev <[email protected]> Cc: Alexander Shishkin <[email protected]> Cc: Arnaldo Carvalho de Melo <[email protected]> Cc: Artyom Kuanbekov <[email protected]> Cc: David Carrillo-Cisneros <[email protected]> Cc: David Woodhouse <[email protected]> Cc: H. Peter Anvin <[email protected]> Cc: Jiri Olsa <[email protected]> Cc: Kan Liang <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Matt Wilson <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Stephane Eranian <[email protected]> Cc: Thomas Gleixner <[email protected]> Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Ingo Molnar <[email protected]> --- arch/x86/events/intel/core.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c index eab0915..a74a2db 100644 --- a/arch/x86/events/intel/core.c +++ b/arch/x86/events/intel/core.c @@ -3607,10 +3607,14 @@ __init int intel_pmu_init(void) /* * Quirk: v2 perfmon does not report fixed-purpose events, so - * assume at least 3 events: + * assume at least 3 events, when not running in a hypervisor: */ - if (version > 1) - x86_pmu.num_counters_fixed = max((int)edx.split.num_counters_fixed, 3); + if (version > 1) { + int assume = 3 * !boot_cpu_has(X86_FEATURE_HYPERVISOR); + + x86_pmu.num_counters_fixed = + max((int)edx.split.num_counters_fixed, assume); + } if (boot_cpu_has(X86_FEATURE_PDCM)) { u64 capabilities;
