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Date: Tue, 30 Nov 2010 18:10:46 -0200
From: Arnaldo Carvalho de Melo <acme@...radead.org>
To: Ingo Molnar <mingo@...e.hu>
Cc: linux-kernel@...r.kernel.org,
Arnaldo Carvalho de Melo <acme@...hat.com>,
Frédéric Weisbecker <fweisbec@...il.com>,
Ian Munsie <imunsie@....ibm.com>,
Mike Galbraith <efault@....de>,
Peter Zijlstra <a.p.zijlstra@...llo.nl>,
Paul Mackerras <paulus@...ba.org>,
Stephane Eranian <eranian@...gle.com>
Subject: [PATCH 01/11] perf events: Precalculate the header space for PERF_SAMPLE_ fields
From: Arnaldo Carvalho de Melo <acme@...hat.com>
PERF_SAMPLE_{CALLCHAIN,RAW} have variable lenghts per sample, but the others
can be precalculated, reducing a bit the per sample cost.
Acked-by: Peter Zijlstra <a.p.zijlstra@...llo.nl>
Cc: Frédéric Weisbecker <fweisbec@...il.com>
Cc: Ian Munsie <imunsie@....ibm.com>
Cc: Mike Galbraith <efault@....de>
Cc: Peter Zijlstra <a.p.zijlstra@...llo.nl>
Cc: Paul Mackerras <paulus@...ba.org>
Cc: Stephane Eranian <eranian@...gle.com>
LKML-Reference: <new-submission>
Signed-off-by: Arnaldo Carvalho de Melo <acme@...hat.com>
---
include/linux/perf_event.h | 2 +
kernel/perf_event.c | 150 ++++++++++++++++++++++++++-----------------
2 files changed, 93 insertions(+), 59 deletions(-)
diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index cbf04cc..adf6d99 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -758,6 +758,8 @@ struct perf_event {
u64 shadow_ctx_time;
struct perf_event_attr attr;
+ u16 header_size;
+ u16 read_size;
struct hw_perf_event hw;
struct perf_event_context *ctx;
diff --git a/kernel/perf_event.c b/kernel/perf_event.c
index af1e63f..aede712 100644
--- a/kernel/perf_event.c
+++ b/kernel/perf_event.c
@@ -312,9 +312,75 @@ list_add_event(struct perf_event *event, struct perf_event_context *ctx)
ctx->nr_stat++;
}
+/*
+ * Called at perf_event creation and when events are attached/detached from a
+ * group.
+ */
+static void perf_event__read_size(struct perf_event *event)
+{
+ int entry = sizeof(u64); /* value */
+ int size = 0;
+ int nr = 1;
+
+ if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
+ size += sizeof(u64);
+
+ if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
+ size += sizeof(u64);
+
+ if (event->attr.read_format & PERF_FORMAT_ID)
+ entry += sizeof(u64);
+
+ if (event->attr.read_format & PERF_FORMAT_GROUP) {
+ nr += event->group_leader->nr_siblings;
+ size += sizeof(u64);
+ }
+
+ size += entry * nr;
+ event->read_size = size;
+}
+
+static void perf_event__header_size(struct perf_event *event)
+{
+ struct perf_sample_data *data;
+ u64 sample_type = event->attr.sample_type;
+ u16 size = 0;
+
+ perf_event__read_size(event);
+
+ if (sample_type & PERF_SAMPLE_IP)
+ size += sizeof(data->ip);
+
+ if (sample_type & PERF_SAMPLE_TID)
+ size += sizeof(data->tid_entry);
+
+ if (sample_type & PERF_SAMPLE_TIME)
+ size += sizeof(data->time);
+
+ if (sample_type & PERF_SAMPLE_ADDR)
+ size += sizeof(data->addr);
+
+ if (sample_type & PERF_SAMPLE_ID)
+ size += sizeof(data->id);
+
+ if (sample_type & PERF_SAMPLE_STREAM_ID)
+ size += sizeof(data->stream_id);
+
+ if (sample_type & PERF_SAMPLE_CPU)
+ size += sizeof(data->cpu_entry);
+
+ if (sample_type & PERF_SAMPLE_PERIOD)
+ size += sizeof(data->period);
+
+ if (sample_type & PERF_SAMPLE_READ)
+ size += event->read_size;
+
+ event->header_size = size;
+}
+
static void perf_group_attach(struct perf_event *event)
{
- struct perf_event *group_leader = event->group_leader;
+ struct perf_event *group_leader = event->group_leader, *pos;
/*
* We can have double attach due to group movement in perf_event_open.
@@ -333,6 +399,11 @@ static void perf_group_attach(struct perf_event *event)
list_add_tail(&event->group_entry, &group_leader->sibling_list);
group_leader->nr_siblings++;
+
+ perf_event__header_size(group_leader);
+
+ list_for_each_entry(pos, &group_leader->sibling_list, group_entry)
+ perf_event__header_size(pos);
}
/*
@@ -391,7 +462,7 @@ static void perf_group_detach(struct perf_event *event)
if (event->group_leader != event) {
list_del_init(&event->group_entry);
event->group_leader->nr_siblings--;
- return;
+ goto out;
}
if (!list_empty(&event->group_entry))
@@ -410,6 +481,12 @@ static void perf_group_detach(struct perf_event *event)
/* Inherit group flags from the previous leader */
sibling->group_flags = event->group_flags;
}
+
+out:
+ perf_event__header_size(event->group_leader);
+
+ list_for_each_entry(tmp, &event->group_leader->sibling_list, group_entry)
+ perf_event__header_size(tmp);
}
static inline int
@@ -2289,31 +2366,6 @@ static int perf_release(struct inode *inode, struct file *file)
return perf_event_release_kernel(event);
}
-static int perf_event_read_size(struct perf_event *event)
-{
- int entry = sizeof(u64); /* value */
- int size = 0;
- int nr = 1;
-
- if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
- size += sizeof(u64);
-
- if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
- size += sizeof(u64);
-
- if (event->attr.read_format & PERF_FORMAT_ID)
- entry += sizeof(u64);
-
- if (event->attr.read_format & PERF_FORMAT_GROUP) {
- nr += event->group_leader->nr_siblings;
- size += sizeof(u64);
- }
-
- size += entry * nr;
-
- return size;
-}
-
u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
{
struct perf_event *child;
@@ -2428,7 +2480,7 @@ perf_read_hw(struct perf_event *event, char __user *buf, size_t count)
if (event->state == PERF_EVENT_STATE_ERROR)
return 0;
- if (count < perf_event_read_size(event))
+ if (count < event->read_size)
return -ENOSPC;
WARN_ON_ONCE(event->ctx->parent_ctx);
@@ -3606,59 +3658,34 @@ void perf_prepare_sample(struct perf_event_header *header,
data->type = sample_type;
header->type = PERF_RECORD_SAMPLE;
- header->size = sizeof(*header);
+ header->size = sizeof(*header) + event->header_size;
header->misc = 0;
header->misc |= perf_misc_flags(regs);
- if (sample_type & PERF_SAMPLE_IP) {
+ if (sample_type & PERF_SAMPLE_IP)
data->ip = perf_instruction_pointer(regs);
- header->size += sizeof(data->ip);
- }
-
if (sample_type & PERF_SAMPLE_TID) {
/* namespace issues */
data->tid_entry.pid = perf_event_pid(event, current);
data->tid_entry.tid = perf_event_tid(event, current);
-
- header->size += sizeof(data->tid_entry);
}
- if (sample_type & PERF_SAMPLE_TIME) {
+ if (sample_type & PERF_SAMPLE_TIME)
data->time = perf_clock();
- header->size += sizeof(data->time);
- }
-
- if (sample_type & PERF_SAMPLE_ADDR)
- header->size += sizeof(data->addr);
-
- if (sample_type & PERF_SAMPLE_ID) {
+ if (sample_type & PERF_SAMPLE_ID)
data->id = primary_event_id(event);
- header->size += sizeof(data->id);
- }
-
- if (sample_type & PERF_SAMPLE_STREAM_ID) {
+ if (sample_type & PERF_SAMPLE_STREAM_ID)
data->stream_id = event->id;
- header->size += sizeof(data->stream_id);
- }
-
if (sample_type & PERF_SAMPLE_CPU) {
data->cpu_entry.cpu = raw_smp_processor_id();
data->cpu_entry.reserved = 0;
-
- header->size += sizeof(data->cpu_entry);
}
- if (sample_type & PERF_SAMPLE_PERIOD)
- header->size += sizeof(data->period);
-
- if (sample_type & PERF_SAMPLE_READ)
- header->size += perf_event_read_size(event);
-
if (sample_type & PERF_SAMPLE_CALLCHAIN) {
int size = 1;
@@ -3726,7 +3753,7 @@ perf_event_read_event(struct perf_event *event,
.header = {
.type = PERF_RECORD_READ,
.misc = 0,
- .size = sizeof(read_event) + perf_event_read_size(event),
+ .size = sizeof(read_event) + event->read_size,
},
.pid = perf_event_pid(event, task),
.tid = perf_event_tid(event, task),
@@ -5715,6 +5742,11 @@ SYSCALL_DEFINE5(perf_event_open,
mutex_unlock(¤t->perf_event_mutex);
/*
+ * Precalculate sample_data sizes
+ */
+ perf_event__header_size(event);
+
+ /*
* Drop the reference on the group_event after placing the
* new event on the sibling_list. This ensures destruction
* of the group leader will find the pointer to itself in
--
1.6.2.5
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