[PATCH 2/5] perf events: Separate the routines handling the PERF_SAMPLE_ identity fields

From: Arnaldo Carvalho de Melo
Date: Sat Dec 04 2010 - 17:27:34 EST


From: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>

Those will be made available in sample like events like MMAP, EXEC, etc in a
followup patch. So precalculate the extra id header space and have a separate
routine to fill them up.

V2: Thomas noticed that the id header needs to be precalculated at
inherit_events too:

LKML-Reference: <alpine.LFD.2.00.1012031245220.2653@xxxxxxxxxxxxxxxxxxxxxxx>

Tested-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Reviewed-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Acked-by: Ian Munsie <imunsie@xxxxxxxxxxx>
Acked-by: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Acked-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: FrÃdÃric Weisbecker <fweisbec@xxxxxxxxx>
Cc: Ian Munsie <imunsie@xxxxxxxxxxx>
Cc: Mike Galbraith <efault@xxxxxx>
Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxx>
Cc: Stephane Eranian <eranian@xxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
LKML-Reference: <1291318772-30880-2-git-send-email-acme@xxxxxxxxxxxxx>
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
include/linux/perf_event.h | 1 +
kernel/perf_event.c | 129 +++++++++++++++++++++++++------------------
2 files changed, 76 insertions(+), 54 deletions(-)

diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index adf6d99..b9950b1 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -759,6 +759,7 @@ struct perf_event {

struct perf_event_attr attr;
u16 header_size;
+ u16 id_header_size;
u16 read_size;
struct hw_perf_event hw;

diff --git a/kernel/perf_event.c b/kernel/perf_event.c
index 7961b27..a047997 100644
--- a/kernel/perf_event.c
+++ b/kernel/perf_event.c
@@ -133,6 +133,28 @@ static void unclone_ctx(struct perf_event_context *ctx)
}
}

+static u32 perf_event_pid(struct perf_event *event, struct task_struct *p)
+{
+ /*
+ * only top level events have the pid namespace they were created in
+ */
+ if (event->parent)
+ event = event->parent;
+
+ return task_tgid_nr_ns(p, event->ns);
+}
+
+static u32 perf_event_tid(struct perf_event *event, struct task_struct *p)
+{
+ /*
+ * only top level events have the pid namespace they were created in
+ */
+ if (event->parent)
+ event = event->parent;
+
+ return task_pid_nr_ns(p, event->ns);
+}
+
/*
* If we inherit events we want to return the parent event id
* to userspace.
@@ -351,15 +373,30 @@ static void perf_event__header_size(struct perf_event *event)
if (sample_type & PERF_SAMPLE_IP)
size += sizeof(data->ip);

+ if (sample_type & PERF_SAMPLE_ADDR)
+ size += sizeof(data->addr);
+
+ 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_event__id_header_size(struct perf_event *event)
+{
+ struct perf_sample_data *data;
+ u64 sample_type = event->attr.sample_type;
+ u16 size = 0;
+
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);

@@ -369,13 +406,7 @@ static void perf_event__header_size(struct perf_event *event)
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;
+ event->id_header_size = size;
}

static void perf_group_attach(struct perf_event *event)
@@ -3357,6 +3388,36 @@ __always_inline void perf_output_copy(struct perf_output_handle *handle,
} while (len);
}

+static void perf_event_header__init_id(struct perf_event_header *header,
+ struct perf_sample_data *data,
+ struct perf_event *event)
+{
+ u64 sample_type = event->attr.sample_type;
+
+ data->type = sample_type;
+ header->size += event->id_header_size;
+
+ 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);
+ }
+
+ if (sample_type & PERF_SAMPLE_TIME)
+ data->time = perf_clock();
+
+ if (sample_type & PERF_SAMPLE_ID)
+ data->id = primary_event_id(event);
+
+ if (sample_type & PERF_SAMPLE_STREAM_ID)
+ data->stream_id = event->id;
+
+ if (sample_type & PERF_SAMPLE_CPU) {
+ data->cpu_entry.cpu = raw_smp_processor_id();
+ data->cpu_entry.reserved = 0;
+ }
+}
+
int perf_output_begin(struct perf_output_handle *handle,
struct perf_event *event, unsigned int size,
int nmi, int sample)
@@ -3459,28 +3520,6 @@ void perf_output_end(struct perf_output_handle *handle)
rcu_read_unlock();
}

-static u32 perf_event_pid(struct perf_event *event, struct task_struct *p)
-{
- /*
- * only top level events have the pid namespace they were created in
- */
- if (event->parent)
- event = event->parent;
-
- return task_tgid_nr_ns(p, event->ns);
-}
-
-static u32 perf_event_tid(struct perf_event *event, struct task_struct *p)
-{
- /*
- * only top level events have the pid namespace they were created in
- */
- if (event->parent)
- event = event->parent;
-
- return task_pid_nr_ns(p, event->ns);
-}
-
static void perf_output_read_one(struct perf_output_handle *handle,
struct perf_event *event,
u64 enabled, u64 running)
@@ -3655,37 +3694,17 @@ void perf_prepare_sample(struct perf_event_header *header,
{
u64 sample_type = event->attr.sample_type;

- data->type = sample_type;
-
header->type = PERF_RECORD_SAMPLE;
header->size = sizeof(*header) + event->header_size;

header->misc = 0;
header->misc |= perf_misc_flags(regs);

+ perf_event_header__init_id(header, data, event);
+
if (sample_type & PERF_SAMPLE_IP)
data->ip = perf_instruction_pointer(regs);

- 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);
- }
-
- if (sample_type & PERF_SAMPLE_TIME)
- data->time = perf_clock();
-
- if (sample_type & PERF_SAMPLE_ID)
- data->id = primary_event_id(event);
-
- if (sample_type & PERF_SAMPLE_STREAM_ID)
- data->stream_id = event->id;
-
- if (sample_type & PERF_SAMPLE_CPU) {
- data->cpu_entry.cpu = raw_smp_processor_id();
- data->cpu_entry.reserved = 0;
- }
-
if (sample_type & PERF_SAMPLE_CALLCHAIN) {
int size = 1;

@@ -5745,6 +5764,7 @@ SYSCALL_DEFINE5(perf_event_open,
* Precalculate sample_data sizes
*/
perf_event__header_size(event);
+ perf_event__id_header_size(event);

/*
* Drop the reference on the group_event after placing the
@@ -6102,6 +6122,7 @@ inherit_event(struct perf_event *parent_event,
* Precalculate sample_data sizes
*/
perf_event__header_size(child_event);
+ perf_event__id_header_size(child_event);

/*
* Link it up in the child's context:
--
1.6.2.5

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