From: Ingo Molnar Date: Mon, 4 May 2009 17:04:09 +0000 (+0200) Subject: perf_counter: fix fixed-purpose counter support on v2 Intel-PERFMON X-Git-Tag: firefly_0821_release~13973^2~302 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=066d7dea32c9bffe6decc0abe465627656cdd84e;p=firefly-linux-kernel-4.4.55.git perf_counter: fix fixed-purpose counter support on v2 Intel-PERFMON Fixed-purpose counters stopped working in a simple 'perf stat ls' run: cache references cache misses Due to: ef7b3e0: perf_counter, x86: remove vendor check in fixed_mode_idx() Which made x86_pmu.num_counters_fixed matter: if it's nonzero, the fixed-purpose counters are utilized. But on v2 perfmon this field is not set (despite there being fixed-purpose PMCs). So add a quirk to set the number of fixed-purpose counters to at least three. [ Impact: add quirk for three fixed-purpose counters on certain Intel CPUs ] Cc: Robert Richter Cc: Paul Mackerras Cc: Peter Zijlstra LKML-Reference: <1241002046-8832-28-git-send-email-robert.richter@amd.com> Signed-off-by: Ingo Molnar --- diff --git a/arch/x86/kernel/cpu/perf_counter.c b/arch/x86/kernel/cpu/perf_counter.c index 196b58f04448..a6878b0798e5 100644 --- a/arch/x86/kernel/cpu/perf_counter.c +++ b/arch/x86/kernel/cpu/perf_counter.c @@ -962,7 +962,13 @@ static int intel_pmu_init(void) x86_pmu = intel_pmu; x86_pmu.version = version; x86_pmu.num_counters = eax.split.num_counters; - x86_pmu.num_counters_fixed = edx.split.num_counters_fixed; + + /* + * Quirk: v2 perfmon does not report fixed-purpose counters, so + * assume at least 3 counters: + */ + x86_pmu.num_counters_fixed = max((int)edx.split.num_counters_fixed, 3); + x86_pmu.counter_bits = eax.split.bit_width; x86_pmu.counter_mask = (1ULL << eax.split.bit_width) - 1;