From: Peter Zijlstra <pet...@infradead.org>
Due to a discussion with Adrian I had a good look at the perf_event_type record
layout and found the documentation to be somewhat unclear.
Cc: Adrian Hunter <adrian.hun...@intel.com>
Signed-off-by: Peter Zijlstra <a.p.zijls...@chello.nl>
---
include/uapi/linux/perf_event.h | 19 ++++++++++++++++++-
kernel/events/core.c | 31 ++++++++++++++++---------------
2 files changed, 34 insertions(+), 16 deletions(-)
diff --git a/include/uapi/linux/perf_event.h b/include/uapi/linux/perf_event.h
index 0b1df41..876a18c 100644
--- a/include/uapi/linux/perf_event.h
+++ b/include/uapi/linux/perf_event.h
@@ -478,6 +478,16 @@ enum perf_event_type {
* file will be supported by older perf tools, with these new optional
* fields being ignored.
*
+ * struct sample_id {
+ * { u32 pid, tid; } && PERF_SAMPLE_TID
+ * { u64 time; } && PERF_SAMPLE_TIME
+ * { u64 id; } && PERF_SAMPLE_ID
+ * { u64 stream_id;} && PERF_SAMPLE_STREAM_ID
+ * { u32 cpu, res; } && PERF_SAMPLE_CPU
+ * } && perf_event_attr.sample_id_all
+ */
+
+ /*
* The MMAP events record the PROT_EXEC mappings so that we can
* correlate userspace IPs to code. They have the following structure:
*
@@ -489,6 +499,7 @@ enum perf_event_type {
* u64 len;
* u64 pgoff;
* char filename[];
+ * struct sample_id sample_id;
* };
*/
PERF_RECORD_MMAP = 1,
@@ -498,6 +509,7 @@ enum perf_event_type {
* struct perf_event_header header;
* u64 id;
* u64 lost;
+ * struct sample_id sample_id;
* };
*/
PERF_RECORD_LOST = 2,
@@ -508,6 +520,7 @@ enum perf_event_type {
*
* u32 pid, tid;
* char comm[];
+ * struct sample_id sample_id;
* };
*/
PERF_RECORD_COMM = 3,
@@ -518,6 +531,7 @@ enum perf_event_type {
* u32 pid, ppid;
* u32 tid, ptid;
* u64 time;
+ * struct sample_id sample_id;
* };
*/
PERF_RECORD_EXIT = 4,
@@ -528,6 +542,7 @@ enum perf_event_type {
* u64 time;
* u64 id;
* u64 stream_id;
+ * struct sample_id sample_id;
* };
*/
PERF_RECORD_THROTTLE = 5,
@@ -539,6 +554,7 @@ enum perf_event_type {
* u32 pid, ppid;
* u32 tid, ptid;
* u64 time;
+ * struct sample_id sample_id;
* };
*/
PERF_RECORD_FORK = 7,
@@ -549,6 +565,7 @@ enum perf_event_type {
* u32 pid, tid;
*
* struct read_format values;
+ * struct sample_id sample_id;
* };
*/
PERF_RECORD_READ = 8,
@@ -596,7 +613,7 @@ enum perf_event_type {
* u64 dyn_size; } && PERF_SAMPLE_STACK_USER
*
* { u64 weight; } && PERF_SAMPLE_WEIGHT
- * { u64 data_src; } && PERF_SAMPLE_DATA_SRC
+ * { u64 data_src; } && PERF_SAMPLE_DATA_SRC
* };
*/
PERF_RECORD_SAMPLE = 9,
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 708ab70..c9ef899 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -4462,20 +4462,6 @@ void perf_output_sample(struct perf_output_handle
*handle,
}
}
- if (!event->attr.watermark) {
- int wakeup_events = event->attr.wakeup_events;
-
- if (wakeup_events) {
- struct ring_buffer *rb = handle->rb;
- int events = local_inc_return(&rb->events);
-
- if (events >= wakeup_events) {
- local_sub(wakeup_events, &rb->events);
- local_inc(&rb->wakeup);
- }
- }
- }
-
if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
if (data->br_stack) {
size_t size;
@@ -4511,16 +4497,31 @@ void perf_output_sample(struct perf_output_handle
*handle,
}
}
- if (sample_type & PERF_SAMPLE_STACK_USER)
+ if (sample_type & PERF_SAMPLE_STACK_USER) {
perf_output_sample_ustack(handle,
data->stack_user_size,
data->regs_user.regs);
+ }
if (sample_type & PERF_SAMPLE_WEIGHT)
perf_output_put(handle, data->weight);
if (sample_type & PERF_SAMPLE_DATA_SRC)
perf_output_put(handle, data->data_src.val);
+
+ if (!event->attr.watermark) {
+ int wakeup_events = event->attr.wakeup_events;
+
+ if (wakeup_events) {
+ struct ring_buffer *rb = handle->rb;
+ int events = local_inc_return(&rb->events);
+
+ if (events >= wakeup_events) {
+ local_sub(wakeup_events, &rb->events);
+ local_inc(&rb->wakeup);
+ }
+ }
+ }
}
void perf_prepare_sample(struct perf_event_header *header,
--
1.7.11.7
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