From b00233b5306512a09e339d69ef5e390a77f2d302 Mon Sep 17 00:00:00 2001 From: Andi Kleen Date: Tue, 22 Aug 2017 11:52:01 -0700 Subject: 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 Signed-off-by: Peter Zijlstra (Intel) Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/20170822185201.9261-3-andi@firstfloor.org Signed-off-by: Ingo Molnar --- arch/x86/events/core.c | 34 +++++++++++++++++++++++----------- 1 file changed, 23 insertions(+), 11 deletions(-) (limited to 'arch/x86/events/core.c') 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, }; -- cgit v1.2.3 From 5da382eb6ea37e2c49ef521c636d73f6ecc3fa81 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Mon, 28 Aug 2017 12:46:50 +0200 Subject: perf/x86: Fix caps/ for !Intel Move the 'max_precise' capability into generic x86 code where it belongs. This fixes a sysfs splat on !Intel systems where we fail to set x86_pmu_caps_group.atts. Reported-and-tested-by: Borislav Petkov Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Andi Kleen Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: hpa@zytor.com Fixes: 22688d1c20f5 ("x86/perf: Export some PMU attributes in caps/ directory") Link: http://lkml.kernel.org/r/20170828104650.2u3rsim4jafyjzv2@hirez.programming.kicks-ass.net Signed-off-by: Ingo Molnar --- arch/x86/events/core.c | 33 ++++++++++++++++++++++++++++----- arch/x86/events/intel/core.c | 14 ++------------ 2 files changed, 30 insertions(+), 17 deletions(-) (limited to 'arch/x86/events/core.c') diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c index d5f98095a155..73a6311c8baa 100644 --- a/arch/x86/events/core.c +++ b/arch/x86/events/core.c @@ -1757,10 +1757,7 @@ 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 struct attribute_group x86_pmu_caps_group; static int __init init_hw_perf_events(void) { @@ -1808,7 +1805,14 @@ 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.caps_attrs) { + struct attribute **tmp; + + tmp = merge_attr(x86_pmu_caps_group.attrs, x86_pmu.caps_attrs); + if (!WARN_ON(!tmp)) + x86_pmu_caps_group.attrs = tmp; + } if (x86_pmu.event_attrs) x86_pmu_events_group.attrs = x86_pmu.event_attrs; @@ -2224,6 +2228,25 @@ static struct attribute_group x86_pmu_attr_group = { .attrs = x86_pmu_attrs, }; +static ssize_t max_precise_show(struct device *cdev, + struct device_attribute *attr, + char *buf) +{ + return snprintf(buf, PAGE_SIZE, "%d\n", x86_pmu_max_precise()); +} + +static DEVICE_ATTR_RO(max_precise); + +static struct attribute *x86_pmu_caps_attrs[] = { + &dev_attr_max_precise.attr, + NULL +}; + +static struct attribute_group x86_pmu_caps_group = { + .name = "caps", + .attrs = x86_pmu_caps_attrs, +}; + static const struct attribute_group *x86_pmu_attr_groups[] = { &x86_pmu_attr_group, &x86_pmu_format_group, diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c index 8fa2abd9c8b6..829e89cfcee2 100644 --- a/arch/x86/events/intel/core.c +++ b/arch/x86/events/intel/core.c @@ -3820,19 +3820,9 @@ static ssize_t pmu_name_show(struct device *cdev, static DEVICE_ATTR_RO(pmu_name); -static ssize_t max_precise_show(struct device *cdev, - struct device_attribute *attr, - char *buf) -{ - return snprintf(buf, PAGE_SIZE, "%d\n", x86_pmu_max_precise()); -} - -static DEVICE_ATTR_RO(max_precise); - static struct attribute *intel_pmu_caps_attrs[] = { - &dev_attr_pmu_name.attr, - &dev_attr_max_precise.attr, - NULL + &dev_attr_pmu_name.attr, + NULL }; static struct attribute *intel_pmu_attrs[] = { -- cgit v1.2.3