From: Arnaldo Carvalho de Melo <acme@kernel.org>
To: Ingo Molnar <mingo@kernel.org>
Cc: linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org,
Jiri Olsa <jolsa@kernel.org>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Andi Kleen <ak@linux.intel.com>, David Ahern <dsahern@gmail.com>,
Namhyung Kim <namhyung@kernel.org>,
Arnaldo Carvalho de Melo <acme@redhat.com>
Subject: [PATCH 15/27] perf: Allocate context task_ctx_data for child event
Date: Wed, 10 Jan 2018 18:28:32 -0300 [thread overview]
Message-ID: <20180110212844.12441-16-acme@kernel.org> (raw)
In-Reply-To: <20180110212844.12441-1-acme@kernel.org>
From: Jiri Olsa <jolsa@kernel.org>
Currently we use perf_event_context::task_ctx_data to save and restore
the LBR status when the task is scheduled out and in.
We don't allocate it for child contexts, which results in shorter task's
LBR stack, because we don't save the history from previous run and start
over every time we schedule the task in.
I made a test to generate samples with LBR call stack and got higher
numbers on bigger chain depths:
before: after:
LBR call chain: nr: 1 60561 498127
LBR call chain: nr: 2 0 0
LBR call chain: nr: 3 107030 2172
LBR call chain: nr: 4 466685 62758
LBR call chain: nr: 5 2307319 878046
LBR call chain: nr: 6 48713 495218
LBR call chain: nr: 7 1040 4551
LBR call chain: nr: 8 481 172
LBR call chain: nr: 9 878 120
LBR call chain: nr: 10 2377 6698
LBR call chain: nr: 11 28830 151487
LBR call chain: nr: 12 29347 339867
LBR call chain: nr: 13 4 22
LBR call chain: nr: 14 3 53
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Fixes: 4af57ef28c2c ("perf: Add pmu specific data for perf task context")
Link: http://lkml.kernel.org/r/20180107160356.28203-4-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
kernel/events/core.c | 14 ++++++++++++++
1 file changed, 14 insertions(+)
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 4df5b695bf0d..55fb648a32b0 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -10703,6 +10703,19 @@ inherit_event(struct perf_event *parent_event,
if (IS_ERR(child_event))
return child_event;
+
+ if ((child_event->attach_state & PERF_ATTACH_TASK_DATA) &&
+ !child_ctx->task_ctx_data) {
+ struct pmu *pmu = child_event->pmu;
+
+ child_ctx->task_ctx_data = kzalloc(pmu->task_ctx_size,
+ GFP_KERNEL);
+ if (!child_ctx->task_ctx_data) {
+ free_event(child_event);
+ return NULL;
+ }
+ }
+
/*
* is_orphaned_event() and list_add_tail(&parent_event->child_list)
* must be under the same lock in order to serialize against
@@ -10713,6 +10726,7 @@ inherit_event(struct perf_event *parent_event,
if (is_orphaned_event(parent_event) ||
!atomic_long_inc_not_zero(&parent_event->refcount)) {
mutex_unlock(&parent_event->child_mutex);
+ /* task_ctx_data is freed with child_ctx */
free_event(child_event);
return NULL;
}
--
2.14.3
next prev parent reply other threads:[~2018-01-10 21:29 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-10 21:28 [GIT PULL 00/27] perf/core improvements and fixes Arnaldo Carvalho de Melo
2018-01-10 21:28 ` [PATCH 01/27] perf test bpf: Improve message about expected samples Arnaldo Carvalho de Melo
2018-01-10 21:28 ` [PATCH 02/27] perf test bpf: Use designated struct field initializers Arnaldo Carvalho de Melo
2018-01-10 21:28 ` [PATCH 03/27] perf test bpf: Hook on epoll_pwait() Arnaldo Carvalho de Melo
2018-01-10 21:28 ` [PATCH 04/27] perf tools: Fix compile error with libunwind x86 Arnaldo Carvalho de Melo
2018-01-10 21:28 ` [PATCH 05/27] perf report: Fix a wrong offset issue when using /proc/kcore Arnaldo Carvalho de Melo
2018-01-10 21:28 ` [PATCH 06/27] perf report: Fix a no annotate browser displayed issue Arnaldo Carvalho de Melo
2018-01-10 21:28 ` [PATCH 07/27] perf header: Add infrastructure to record first and last sample time Arnaldo Carvalho de Melo
2018-01-10 21:28 ` [PATCH 08/27] perf record: Record the first and last sample time in the header Arnaldo Carvalho de Melo
2018-01-11 13:29 ` Paul Clarke
2018-01-11 14:46 ` Arnaldo Carvalho de Melo
2018-01-10 21:28 ` [PATCH 09/27] perf tools: Create function to parse time percent Arnaldo Carvalho de Melo
2018-01-10 21:28 ` [PATCH 10/27] perf tools: Create function to perform multiple time range checking Arnaldo Carvalho de Melo
2018-01-10 21:28 ` [PATCH 11/27] perf report: Support time percent and multiple time ranges Arnaldo Carvalho de Melo
2018-01-10 21:28 ` [PATCH 12/27] perf script: " Arnaldo Carvalho de Melo
2018-01-10 21:28 ` [PATCH 13/27] perf tools: Enable LIBBABELTRACE by default Arnaldo Carvalho de Melo
2018-01-10 21:28 ` [PATCH 14/27] perf tools: Display perf_event_attr::namespaces debug info Arnaldo Carvalho de Melo
2018-01-10 21:28 ` Arnaldo Carvalho de Melo [this message]
2018-01-10 21:28 ` [PATCH 16/27] perf: Add sample_id to PERF_RECORD_ITRACE_START event comment Arnaldo Carvalho de Melo
2018-01-10 21:28 ` [PATCH 17/27] perf: Make perf_callchain function static Arnaldo Carvalho de Melo
2018-01-10 21:28 ` [PATCH 18/27] perf: Return empty callchain instead of NULL Arnaldo Carvalho de Melo
2018-01-10 21:28 ` [PATCH 19/27] perf: Update PERF_RECORD_MISC_* comment for perf_event_header::misc bit 13 Arnaldo Carvalho de Melo
2018-01-10 21:28 ` [PATCH 20/27] perf script: Add support to display sample misc field Arnaldo Carvalho de Melo
2018-01-10 21:28 ` [PATCH 21/27] perf script: Add support to display lost events Arnaldo Carvalho de Melo
2018-01-10 21:28 ` [PATCH 22/27] perf tools: Make the tool's warning messages optional Arnaldo Carvalho de Melo
2018-01-10 21:28 ` [PATCH 23/27] perf report: Add --stats option to display quick data statistics Arnaldo Carvalho de Melo
2018-01-10 21:28 ` [PATCH 24/27] perf trace: Beautify 'gettid' syscall result Arnaldo Carvalho de Melo
2018-01-10 21:28 ` [PATCH 25/27] perf report: Add --tasks option to display monitored tasks Arnaldo Carvalho de Melo
2018-01-10 21:28 ` [PATCH 26/27] perf report: Introduce --mmaps Arnaldo Carvalho de Melo
2018-01-10 21:28 ` [PATCH 27/27] tools headers: Synchronize kernel <-> tooling headers Arnaldo Carvalho de Melo
2018-01-11 5:54 ` [GIT PULL 00/27] perf/core improvements and fixes Ingo Molnar
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