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Date: Tue, 23 Nov 2010 16:35:41 +1100
From: "Ian Munsie" <imunsie@....ibm.com>
To: linux-kernel@...r.kernel.org
Cc: Ian Munsie <imunsie@....ibm.com>,
Peter Zijlstra <a.p.zijlstra@...llo.nl>,
Paul Mackerras <paulus@...ba.org>, Ingo Molnar <mingo@...e.hu>,
Arnaldo Carvalho de Melo <acme@...stprotocols.net>
Subject: [PATCH 3/6] perf: Add timestamp to COMM and MMAP events
From: Ian Munsie <imunsie@....ibm.com>
This patch adds extra ABI to the perf interface to allow the
PERF_RECORD_COMM and PERF_RECORD_MMAP events to optionally include a
timestamp, which they were previously missing.
This has become necessary since the move to per-task-per-cpu events in
perf as those events would not necessarily be recorded prior to any
samples associated with them and would cause perf to miss-attribute
those events and produce bogus reports. This behaviour can be observed
almost every run on 64 CPU PowerPC systems, but has also been observed
on a simple quad core Intel i7.
The timestamp is requested by setting the all_timed flag in the
event attributes when opening the event and will be placed just after
the header of the events in question.
This patch also ensures that the PERF_RECORD_COMM event is dispatched
before enabling the counters for enable_on_exec.
Signed-off-by: Ian Munsie <imunsie@....ibm.com>
---
include/linux/perf_event.h | 5 ++-
kernel/perf_event.c | 95 +++++++++++++++++++++++++------------------
2 files changed, 59 insertions(+), 41 deletions(-)
diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index 40150f3..ef99af4 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -215,8 +215,9 @@ struct perf_event_attr {
*/
precise_ip : 2, /* skid constraint */
mmap_data : 1, /* non-exec mmap data */
+ all_timed : 1, /* timestamp every event */
- __reserved_1 : 46;
+ __reserved_1 : 47;
union {
__u32 wakeup_events; /* wakeup every n events */
@@ -332,6 +333,7 @@ enum perf_event_type {
*
* struct {
* struct perf_event_header header;
+ * { u64 time; } && all_timed
*
* u32 pid, tid;
* u64 addr;
@@ -354,6 +356,7 @@ enum perf_event_type {
/*
* struct {
* struct perf_event_header header;
+ * { u64 time; } && all_timed
*
* u32 pid, tid;
* char comm[];
diff --git a/kernel/perf_event.c b/kernel/perf_event.c
index 8d099f3..c8ebab2 100644
--- a/kernel/perf_event.c
+++ b/kernel/perf_event.c
@@ -3884,9 +3884,9 @@ struct perf_comm_event {
char *comm;
int comm_size;
+ struct perf_event_header header;
+ u64 time; /* && all_timed */
struct {
- struct perf_event_header header;
-
u32 pid;
u32 tid;
} event_id;
@@ -3896,16 +3896,23 @@ static void perf_event_comm_output(struct perf_event *event,
struct perf_comm_event *comm_event)
{
struct perf_output_handle handle;
- int size = comm_event->event_id.header.size;
- int ret = perf_output_begin(&handle, event, size, 0, 0);
- if (ret)
+ if (event->attr.all_timed) {
+ comm_event->header.size += sizeof(u64);
+ comm_event->time = perf_clock();
+ }
+
+ if (perf_output_begin(&handle, event, comm_event->header.size, 0, 0))
return;
comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
+ perf_output_put(&handle, comm_event->header);
+ if (event->attr.all_timed)
+ perf_output_put(&handle, comm_event->time);
perf_output_put(&handle, comm_event->event_id);
+
perf_output_copy(&handle, comm_event->comm,
comm_event->comm_size);
perf_output_end(&handle);
@@ -3913,9 +3920,6 @@ static void perf_event_comm_output(struct perf_event *event,
static int perf_event_comm_match(struct perf_event *event)
{
- if (event->state < PERF_EVENT_STATE_INACTIVE)
- return 0;
-
if (event->cpu != -1 && event->cpu != smp_processor_id())
return 0;
@@ -3952,7 +3956,8 @@ static void perf_event_comm_event(struct perf_comm_event *comm_event)
comm_event->comm = comm;
comm_event->comm_size = size;
- comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
+ comm_event->header.size = sizeof(comm_event->header)
+ + sizeof(comm_event->event_id) + size;
rcu_read_lock();
list_for_each_entry_rcu(pmu, &pmus, entry) {
@@ -3978,33 +3983,34 @@ void perf_event_comm(struct task_struct *task)
struct perf_event_context *ctx;
int ctxn;
- for_each_task_context_nr(ctxn) {
- ctx = task->perf_event_ctxp[ctxn];
- if (!ctx)
- continue;
-
- perf_event_enable_on_exec(ctx);
- }
- if (!atomic_read(&nr_comm_events))
- return;
-
- comm_event = (struct perf_comm_event){
- .task = task,
- /* .comm */
- /* .comm_size */
- .event_id = {
+ if (atomic_read(&nr_comm_events)) {
+ comm_event = (struct perf_comm_event){
+ .task = task,
+ /* .comm */
+ /* .comm_size */
.header = {
.type = PERF_RECORD_COMM,
.misc = 0,
/* .size */
},
- /* .pid */
- /* .tid */
- },
- };
+ /* .time && all_timed */
+ .event_id = {
+ /* .pid */
+ /* .tid */
+ },
+ };
+
+ perf_event_comm_event(&comm_event);
+ }
+
+ for_each_task_context_nr(ctxn) {
+ ctx = task->perf_event_ctxp[ctxn];
+ if (!ctx)
+ continue;
- perf_event_comm_event(&comm_event);
+ perf_event_enable_on_exec(ctx);
+ }
}
/*
@@ -4017,9 +4023,9 @@ struct perf_mmap_event {
const char *file_name;
int file_size;
+ struct perf_event_header header;
+ u64 time; /* && all_timed */
struct {
- struct perf_event_header header;
-
u32 pid;
u32 tid;
u64 start;
@@ -4032,16 +4038,23 @@ static void perf_event_mmap_output(struct perf_event *event,
struct perf_mmap_event *mmap_event)
{
struct perf_output_handle handle;
- int size = mmap_event->event_id.header.size;
- int ret = perf_output_begin(&handle, event, size, 0, 0);
- if (ret)
+ if (event->attr.all_timed) {
+ mmap_event->header.size += sizeof(u64);
+ mmap_event->time = perf_clock();
+ }
+
+ if (perf_output_begin(&handle, event, mmap_event->header.size, 0, 0))
return;
mmap_event->event_id.pid = perf_event_pid(event, current);
mmap_event->event_id.tid = perf_event_tid(event, current);
+ perf_output_put(&handle, mmap_event->header);
+ if (event->attr.all_timed)
+ perf_output_put(&handle, mmap_event->time);
perf_output_put(&handle, mmap_event->event_id);
+
perf_output_copy(&handle, mmap_event->file_name,
mmap_event->file_size);
perf_output_end(&handle);
@@ -4137,7 +4150,8 @@ got_name:
mmap_event->file_name = name;
mmap_event->file_size = size;
- mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
+ mmap_event->header.size = sizeof(mmap_event->header)
+ + sizeof(mmap_event->event_id) + size;
rcu_read_lock();
list_for_each_entry_rcu(pmu, &pmus, entry) {
@@ -4173,12 +4187,13 @@ void perf_event_mmap(struct vm_area_struct *vma)
.vma = vma,
/* .file_name */
/* .file_size */
+ .header = {
+ .type = PERF_RECORD_MMAP,
+ .misc = PERF_RECORD_MISC_USER,
+ /* .size */
+ },
+ /* .time && all_timed */
.event_id = {
- .header = {
- .type = PERF_RECORD_MMAP,
- .misc = PERF_RECORD_MISC_USER,
- /* .size */
- },
/* .pid */
/* .tid */
.start = vma->vm_start,
--
1.7.2.3
--
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