lkml.org 
[lkml]   [2015]   [Sep]   [3]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[[PATCH v6 05/10] perf: Add group reads to perf_event_read()
Date
From: Peter Zijlstra <peterz@infradead.org>

Enable perf_event_read() to update entire groups at once, this will be
useful for read transactions.

Cc: Ingo Molnar <mingo@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20150723080435.GE25159@twins.programming.kicks-ass.net
---
kernel/events/core.c | 39 ++++++++++++++++++++++++++++++++-------
1 file changed, 32 insertions(+), 7 deletions(-)

diff --git a/kernel/events/core.c b/kernel/events/core.c
index be39e63..7bb9141 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -3184,12 +3184,18 @@ void perf_event_exec(void)
rcu_read_unlock();
}

+struct perf_read_data {
+ struct perf_event *event;
+ bool group;
+};
+
/*
* Cross CPU call to read the hardware event
*/
static void __perf_event_read(void *info)
{
- struct perf_event *event = info;
+ struct perf_read_data *data = info;
+ struct perf_event *sub, *event = data->event;
struct perf_event_context *ctx = event->ctx;
struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);

@@ -3208,9 +3214,21 @@ static void __perf_event_read(void *info)
update_context_time(ctx);
update_cgrp_time_from_event(event);
}
+
update_event_times(event);
if (event->state == PERF_EVENT_STATE_ACTIVE)
event->pmu->read(event);
+
+ if (!data->group)
+ goto unlock;
+
+ list_for_each_entry(sub, &event->sibling_list, group_entry) {
+ update_event_times(sub);
+ if (sub->state == PERF_EVENT_STATE_ACTIVE)
+ sub->pmu->read(sub);
+ }
+
+unlock:
raw_spin_unlock(&ctx->lock);
}

@@ -3275,15 +3293,19 @@ u64 perf_event_read_local(struct perf_event *event)
return val;
}

-static void perf_event_read(struct perf_event *event)
+static void perf_event_read(struct perf_event *event, bool group)
{
/*
* If event is enabled and currently active on a CPU, update the
* value in the event structure:
*/
if (event->state == PERF_EVENT_STATE_ACTIVE) {
+ struct perf_read_data data = {
+ .event = event,
+ .group = group,
+ };
smp_call_function_single(event->oncpu,
- __perf_event_read, event, 1);
+ __perf_event_read, &data, 1);
} else if (event->state == PERF_EVENT_STATE_INACTIVE) {
struct perf_event_context *ctx = event->ctx;
unsigned long flags;
@@ -3298,7 +3320,10 @@ static void perf_event_read(struct perf_event *event)
update_context_time(ctx);
update_cgrp_time_from_event(event);
}
- update_event_times(event);
+ if (group)
+ update_group_times(event);
+ else
+ update_event_times(event);
raw_spin_unlock_irqrestore(&ctx->lock, flags);
}
}
@@ -3817,7 +3842,7 @@ u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)

mutex_lock(&event->child_mutex);

- perf_event_read(event);
+ perf_event_read(event, false);
total += perf_event_count(event);

*enabled += event->total_time_enabled +
@@ -3826,7 +3851,7 @@ u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
atomic64_read(&event->child_total_time_running);

list_for_each_entry(child, &event->child_list, child_list) {
- perf_event_read(child);
+ perf_event_read(child, false);
total += perf_event_count(child);
*enabled += child->total_time_enabled;
*running += child->total_time_running;
@@ -3987,7 +4012,7 @@ static unsigned int perf_poll(struct file *file, poll_table *wait)

static void _perf_event_reset(struct perf_event *event)
{
- perf_event_read(event);
+ perf_event_read(event, false);
local64_set(&event->count, 0);
perf_event_update_userpage(event);
}
--
1.7.9.5


\
 
 \ /
  Last update: 2015-09-04 05:21    [W:0.144 / U:7.968 seconds]
©2003-2017 Jasper Spaans. hosted at Digital OceanAdvertise on this site