diff options
| author | Andi Kleen <ak@linux.intel.com> | 2017-08-22 11:52:01 -0700 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2017-08-25 11:04:20 +0200 |
| commit | b00233b5306512a09e339d69ef5e390a77f2d302 (patch) | |
| tree | 7422f4c5242cdecb440392915b36371fe42028c3 /arch/x86/events/core.c | |
| parent | a5df70c354c26e20d5fd8eb64517f724e97ef0b2 (diff) | |
perf/x86: Export some PMU attributes in caps/ directory
It can be difficult to figure out for user programs what features
the x86 CPU PMU driver actually supports. Currently it requires
grepping in dmesg, but dmesg is not always available.
This adds a caps directory to /sys/bus/event_source/devices/cpu/,
similar to the caps already used on intel_pt, which can be used to
discover the available capabilities cleanly.
Three capabilities are defined:
- pmu_name: Underlying CPU name known to the driver
- max_precise: Max precise level supported
- branches: Known depth of LBR.
Example:
% grep . /sys/bus/event_source/devices/cpu/caps/*
/sys/bus/event_source/devices/cpu/caps/branches:32
/sys/bus/event_source/devices/cpu/caps/max_precise:3
/sys/bus/event_source/devices/cpu/caps/pmu_name:skylake
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20170822185201.9261-3-andi@firstfloor.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/events/core.c')
| -rw-r--r-- | arch/x86/events/core.c | 34 |
1 files changed, 23 insertions, 11 deletions
diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c index af12e294caed..d5f98095a155 100644 --- a/arch/x86/events/core.c +++ b/arch/x86/events/core.c @@ -487,22 +487,28 @@ static inline int precise_br_compat(struct perf_event *event) return m == b; } -int x86_pmu_hw_config(struct perf_event *event) +int x86_pmu_max_precise(void) { - if (event->attr.precise_ip) { - int precise = 0; + int precise = 0; + + /* Support for constant skid */ + if (x86_pmu.pebs_active && !x86_pmu.pebs_broken) { + precise++; - /* Support for constant skid */ - if (x86_pmu.pebs_active && !x86_pmu.pebs_broken) { + /* Support for IP fixup */ + if (x86_pmu.lbr_nr || x86_pmu.intel_cap.pebs_format >= 2) precise++; - /* Support for IP fixup */ - if (x86_pmu.lbr_nr || x86_pmu.intel_cap.pebs_format >= 2) - precise++; + if (x86_pmu.pebs_prec_dist) + precise++; + } + return precise; +} - if (x86_pmu.pebs_prec_dist) - precise++; - } +int x86_pmu_hw_config(struct perf_event *event) +{ + if (event->attr.precise_ip) { + int precise = x86_pmu_max_precise(); if (event->attr.precise_ip > precise) return -EOPNOTSUPP; @@ -1752,6 +1758,10 @@ ssize_t x86_event_sysfs_show(char *page, u64 config, u64 event) static struct attribute_group x86_pmu_attr_group; +static struct attribute_group x86_pmu_caps_group = { + .name = "caps", +}; + static int __init init_hw_perf_events(void) { struct x86_pmu_quirk *quirk; @@ -1798,6 +1808,7 @@ static int __init init_hw_perf_events(void) 0, x86_pmu.num_counters, 0, 0); x86_pmu_format_group.attrs = x86_pmu.format_attrs; + x86_pmu_caps_group.attrs = x86_pmu.caps_attrs; if (x86_pmu.event_attrs) x86_pmu_events_group.attrs = x86_pmu.event_attrs; @@ -2217,6 +2228,7 @@ static const struct attribute_group *x86_pmu_attr_groups[] = { &x86_pmu_attr_group, &x86_pmu_format_group, &x86_pmu_events_group, + &x86_pmu_caps_group, NULL, }; |