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authorImre Palik2016-10-21 01:18:59 -0700
committerIngo Molnar2016-10-28 11:06:25 +0200
commitf92b7604149a55cb601fc0b52911b1e11f0f2514 (patch)
tree50645171418cf4b059f559ee5f69eadff23211fc /arch
parent5aab90ce1ec449912a2ebc4d45e0c85dac29e9dd (diff)
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 <imrep@amazon.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Andi Kleen <ak@linux.intel.com> Cc: Alexander Kozyrev <alexander.kozyrev@intel.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Artyom Kuanbekov <artyom.kuanbekov@intel.com> Cc: David Carrillo-Cisneros <davidcc@google.com> Cc: David Woodhouse <dwmw@amazon.co.uk> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Kan Liang <kan.liang@intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Matt Wilson <msw@amazon.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1477037939-15605-1-git-send-email-imrep.amz@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/events/intel/core.c10
1 files changed, 7 insertions, 3 deletions
diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c
index eab0915f5995..a74a2dbc0180 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;