[tip:perf/core] perf/x86/intel/lbr: Allow time stamp for free running PEBSv3

From: tip-bot for Andi Kleen
Date: Tue Aug 04 2015 - 04:57:23 EST


Commit-ID: a7b58d211ba18c9175b139e18b68c86a6bcc3c3f
Gitweb: http://git.kernel.org/tip/a7b58d211ba18c9175b139e18b68c86a6bcc3c3f
Author: Andi Kleen <ak@xxxxxxxxxxxxxxx>
AuthorDate: Wed, 27 May 2015 21:13:14 -0700
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Tue, 4 Aug 2015 10:16:56 +0200

perf/x86/intel/lbr: Allow time stamp for free running PEBSv3

With PEBSv3 the PEBS record contains a time stamp. That means we can allow
free-running PEBS without a PMI even if the user program requested a time stamp.
This avoids the need to use -T to get free running PEBS, and also avoids
any problems with mis-identifying MMAPs later.

Move the free_running_flags state into a variable in x86_pmu and use it.
This only works when no explicit clock_id is set.

Signed-off-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: acme@xxxxxxxxxx
Cc: eranian@xxxxxxxxxx
Cc: jolsa@xxxxxxxxxx
Cc: kan.liang@xxxxxxxxx
Link: http://lkml.kernel.org/r/1432786398-23861-2-git-send-email-andi@xxxxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
arch/x86/kernel/cpu/perf_event.h | 1 +
arch/x86/kernel/cpu/perf_event_intel.c | 15 ++++++++++++++-
arch/x86/kernel/cpu/perf_event_intel_ds.c | 1 +
3 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kernel/cpu/perf_event.h b/arch/x86/kernel/cpu/perf_event.h
index 3474cf2..7378b10 100644
--- a/arch/x86/kernel/cpu/perf_event.h
+++ b/arch/x86/kernel/cpu/perf_event.h
@@ -594,6 +594,7 @@ struct x86_pmu {
struct event_constraint *pebs_constraints;
void (*pebs_aliases)(struct perf_event *event);
int max_pebs_events;
+ unsigned long free_running_flags;

/*
* Intel LBR
diff --git a/arch/x86/kernel/cpu/perf_event_intel.c b/arch/x86/kernel/cpu/perf_event_intel.c
index 71815cf..cb112bf 100644
--- a/arch/x86/kernel/cpu/perf_event_intel.c
+++ b/arch/x86/kernel/cpu/perf_event_intel.c
@@ -2257,6 +2257,15 @@ static void intel_pebs_aliases_snb(struct perf_event *event)
}
}

+static unsigned long intel_pmu_free_running_flags(struct perf_event *event)
+{
+ unsigned long flags = x86_pmu.free_running_flags;
+
+ if (event->attr.use_clockid)
+ flags &= ~PERF_SAMPLE_TIME;
+ return flags;
+}
+
static int intel_pmu_hw_config(struct perf_event *event)
{
int ret = x86_pmu_hw_config(event);
@@ -2267,7 +2276,8 @@ static int intel_pmu_hw_config(struct perf_event *event)
if (event->attr.precise_ip) {
if (!event->attr.freq) {
event->hw.flags |= PERF_X86_EVENT_AUTO_RELOAD;
- if (!(event->attr.sample_type & ~PEBS_FREERUNNING_FLAGS))
+ if (!(event->attr.sample_type &
+ ~intel_pmu_free_running_flags(event)))
event->hw.flags |= PERF_X86_EVENT_FREERUNNING;
}
if (x86_pmu.pebs_aliases)
@@ -2689,6 +2699,8 @@ static __initconst const struct x86_pmu core_pmu = {
.event_map = intel_pmu_event_map,
.max_events = ARRAY_SIZE(intel_perfmon_event_map),
.apic = 1,
+ .free_running_flags = PEBS_FREERUNNING_FLAGS,
+
/*
* Intel PMCs cannot be accessed sanely above 32-bit width,
* so we install an artificial 1<<31 period regardless of
@@ -2727,6 +2739,7 @@ static __initconst const struct x86_pmu intel_pmu = {
.event_map = intel_pmu_event_map,
.max_events = ARRAY_SIZE(intel_perfmon_event_map),
.apic = 1,
+ .free_running_flags = PEBS_FREERUNNING_FLAGS,
/*
* Intel PMCs cannot be accessed sanely above 32 bit width,
* so we install an artificial 1<<31 period regardless of
diff --git a/arch/x86/kernel/cpu/perf_event_intel_ds.c b/arch/x86/kernel/cpu/perf_event_intel_ds.c
index 410270a..03773c2 100644
--- a/arch/x86/kernel/cpu/perf_event_intel_ds.c
+++ b/arch/x86/kernel/cpu/perf_event_intel_ds.c
@@ -1273,6 +1273,7 @@ void __init intel_ds_init(void)
x86_pmu.pebs_record_size =
sizeof(struct pebs_record_skl);
x86_pmu.drain_pebs = intel_pmu_drain_pebs_nhm;
+ x86_pmu.free_running_flags |= PERF_SAMPLE_TIME;
break;

default:
--
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