From: Alexey Budankov <alexey.budankov@linux.intel.com>
To: Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>,
Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Jiri Olsa <jolsa@redhat.com>, Namhyung Kim <namhyung@kernel.org>,
linux-kernel <linux-kernel@vger.kernel.org>,
Andi Kleen <ak@linux.intel.com>
Subject: [PATCH v2 1/3] perf/core: store context switch out type into Perf trace
Date: Thu, 22 Mar 2018 19:11:07 +0300 [thread overview]
Message-ID: <94a1fd9d-f3b1-156a-589b-a8dc9c17464b@linux.intel.com> (raw)
In-Reply-To: <713750a0-7cc1-0a27-7253-12ff4f3c9a8d@linux.intel.com>
Store thread context-switch-out event type into Perf trace as a part of
PERF_RECORD_SWITCH[_CPU_WIDE] records.
Introduced types of switch-out events assumed to be
a) preempt: task->state == TASK_RUNNING and b) yield: !preempt;
New yield event type is encoded using special
PERF_RECORD_MISC_SWITCH_OUT_YIELD bit extending PERF_RECORD_MISC_SWITCH_OUT
meaning traditional preemption switch out event:
misc &= PERF_RECORD_MISC_SWITCH_OUT | PERF_RECORD_MISC_SWITCH_OUT_YIELD
Signed-off-by: Alexey Budankov <alexey.budankov@linux.intel.com>
---
include/uapi/linux/perf_event.h | 5 +++++
kernel/events/core.c | 4 +++-
tools/include/uapi/linux/perf_event.h | 5 +++++
3 files changed, 13 insertions(+), 1 deletion(-)
diff --git a/include/uapi/linux/perf_event.h b/include/uapi/linux/perf_event.h
index 912b85b52344..f5dd823d0ff1 100644
--- a/include/uapi/linux/perf_event.h
+++ b/include/uapi/linux/perf_event.h
@@ -655,6 +655,11 @@ struct perf_event_mmap_page {
* perf_event_attr::precise_ip.
*/
#define PERF_RECORD_MISC_EXACT_IP (1 << 14)
+/*
+ * Indicates that thread explicitly yielded cpu due to
+ * a call of some synchronization API e.g. futex system call
+ */
+#define PERF_RECORD_MISC_SWITCH_OUT_YIELD (1 << 14)
/*
* Reserve the last bit to indicate some extended misc field
*/
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 74a6e8f12a3c..f15af15af474 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -7556,6 +7556,8 @@ static void perf_event_switch(struct task_struct *task,
struct task_struct *next_prev, bool sched_in)
{
struct perf_switch_event switch_event;
+ __u16 switch_type = sched_in ? 0 : PERF_RECORD_MISC_SWITCH_OUT |
+ (task->state == TASK_RUNNING ? 0 : PERF_RECORD_MISC_SWITCH_OUT_YIELD);
/* N.B. caller checks nr_switch_events != 0 */
@@ -7565,7 +7567,7 @@ static void perf_event_switch(struct task_struct *task,
.event_id = {
.header = {
/* .type */
- .misc = sched_in ? 0 : PERF_RECORD_MISC_SWITCH_OUT,
+ .misc = switch_type,
/* .size */
},
/* .next_prev_pid */
diff --git a/tools/include/uapi/linux/perf_event.h b/tools/include/uapi/linux/perf_event.h
index 912b85b52344..f5dd823d0ff1 100644
--- a/tools/include/uapi/linux/perf_event.h
+++ b/tools/include/uapi/linux/perf_event.h
@@ -655,6 +655,11 @@ struct perf_event_mmap_page {
* perf_event_attr::precise_ip.
*/
#define PERF_RECORD_MISC_EXACT_IP (1 << 14)
+/*
+ * Indicates that thread explicitly yielded cpu due to
+ * a call of some synchronization API e.g. futex system call
+ */
+#define PERF_RECORD_MISC_SWITCH_OUT_YIELD (1 << 14)
/*
* Reserve the last bit to indicate some extended misc field
*/
next prev parent reply other threads:[~2018-03-22 16:11 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-22 16:08 [PATCH v2 0/3] perf/core: expose thread context switch out event type to user space Alexey Budankov
2018-03-22 16:11 ` Alexey Budankov [this message]
2018-03-22 16:13 ` [PATCH v1 2/3] perf report: extend raw dump (-D) out with switch out event type Alexey Budankov
2018-03-22 16:16 ` [PATCH v2 3/3] perf script: extend misc field decoding " Alexey Budankov
2018-03-23 9:24 ` [PATCH v2 0/3] perf/core: expose thread context switch out event type to user space Jiri Olsa
2018-03-23 18:05 ` Peter Zijlstra
2018-03-23 20:38 ` Alexey Budankov
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