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From: Wang Nan <wangnan0@huawei.com>
To: Alexei Starovoitov <ast@kernel.org>,
	Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Brendan Gregg <brendan.d.gregg@gmail.com>,
	Daniel Borkmann <daniel@iogearbox.net>,
	"David S. Miller" <davem@davemloft.net>,
	He Kuang <hekuang@huawei.com>, Jiri Olsa <jolsa@kernel.org>,
	Li Zefan <lizefan@huawei.com>,
	Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>,
	Namhyung Kim <namhyung@kernel.org>,
	Peter Zijlstra <peterz@infradead.org>, <pi3orama@163.com>,
	Will Deacon <will.deacon@arm.com>, <linux-kernel@vger.kernel.org>,
	Wang Nan <wangnan0@huawei.com>
Subject: [PATCH 22/54] perf core: Reduce perf event output overhead by new overflow handler
Date: Mon, 25 Jan 2016 09:56:09 +0000	[thread overview]
Message-ID: <1453715801-7732-23-git-send-email-wangnan0@huawei.com> (raw)
In-Reply-To: <1453715801-7732-1-git-send-email-wangnan0@huawei.com>

By creating onward and backward specific overflow handlers and setting
them according to event's backward setting, normal sampling events
don't need checking backward setting of an event any more.

This is the last patch of backward writing patchset. After this patch,
there's no extra overhead introduced to the fast path of sampling
output.

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Cc: He Kuang <hekuang@huawei.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Brendan Gregg <brendan.d.gregg@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
---
 include/linux/perf_event.h  | 17 +++++++++++++++--
 kernel/events/core.c        | 41 ++++++++++++++++++++++++++++++++++++-----
 kernel/events/ring_buffer.c | 12 ++++++++++++
 3 files changed, 63 insertions(+), 7 deletions(-)

diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index 54c3fb2..c0335b9 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -830,9 +830,15 @@ extern int perf_event_overflow(struct perf_event *event,
 				 struct perf_sample_data *data,
 				 struct pt_regs *regs);
 
+extern void perf_event_output_onward(struct perf_event *event,
+				     struct perf_sample_data *data,
+				     struct pt_regs *regs);
+extern void perf_event_output_backward(struct perf_event *event,
+				       struct perf_sample_data *data,
+				       struct pt_regs *regs);
 extern void perf_event_output(struct perf_event *event,
-				struct perf_sample_data *data,
-				struct pt_regs *regs);
+			      struct perf_sample_data *data,
+			      struct pt_regs *regs);
 
 extern void
 perf_event_header__init_id(struct perf_event_header *header,
@@ -1039,6 +1045,13 @@ static inline bool is_write_backward(struct perf_event *event)
 
 extern int perf_output_begin(struct perf_output_handle *handle,
 			     struct perf_event *event, unsigned int size);
+extern int perf_output_begin_onward(struct perf_output_handle *handle,
+				    struct perf_event *event,
+				    unsigned int size);
+extern int perf_output_begin_backward(struct perf_output_handle *handle,
+				      struct perf_event *event,
+				      unsigned int size);
+
 extern void perf_output_end(struct perf_output_handle *handle);
 extern unsigned int perf_output_copy(struct perf_output_handle *handle,
 			     const void *buf, unsigned int len);
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 8ad22a5..8a25e46 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -5541,9 +5541,13 @@ void perf_prepare_sample(struct perf_event_header *header,
 	}
 }
 
-void perf_event_output(struct perf_event *event,
-			struct perf_sample_data *data,
-			struct pt_regs *regs)
+static void __always_inline
+__perf_event_output(struct perf_event *event,
+		    struct perf_sample_data *data,
+		    struct pt_regs *regs,
+		    int (*output_begin)(struct perf_output_handle *,
+					struct perf_event *,
+					unsigned int))
 {
 	struct perf_output_handle handle;
 	struct perf_event_header header;
@@ -5553,7 +5557,7 @@ void perf_event_output(struct perf_event *event,
 
 	perf_prepare_sample(&header, data, event, regs);
 
-	if (perf_output_begin(&handle, event, header.size))
+	if (output_begin(&handle, event, header.size))
 		goto exit;
 
 	perf_output_sample(&handle, &header, data, event);
@@ -5564,6 +5568,30 @@ exit:
 	rcu_read_unlock();
 }
 
+void
+perf_event_output_onward(struct perf_event *event,
+			 struct perf_sample_data *data,
+			 struct pt_regs *regs)
+{
+	__perf_event_output(event, data, regs, perf_output_begin_onward);
+}
+
+void
+perf_event_output_backward(struct perf_event *event,
+			   struct perf_sample_data *data,
+			   struct pt_regs *regs)
+{
+	__perf_event_output(event, data, regs, perf_output_begin_backward);
+}
+
+void
+perf_event_output(struct perf_event *event,
+		  struct perf_sample_data *data,
+		  struct pt_regs *regs)
+{
+	__perf_event_output(event, data, regs, perf_output_begin);
+}
+
 /*
  * read event_id
  */
@@ -7874,8 +7902,11 @@ perf_event_alloc(struct perf_event_attr *attr, int cpu,
 	if (overflow_handler) {
 		event->overflow_handler	= overflow_handler;
 		event->overflow_handler_context = context;
+	} else if (is_write_backward(event)){
+		event->overflow_handler = perf_event_output_backward;
+		event->overflow_handler_context = NULL;
 	} else {
-		event->overflow_handler = perf_event_output;
+		event->overflow_handler = perf_event_output_onward;
 		event->overflow_handler_context = NULL;
 	}
 
diff --git a/kernel/events/ring_buffer.c b/kernel/events/ring_buffer.c
index 28543e1..ca11809 100644
--- a/kernel/events/ring_buffer.c
+++ b/kernel/events/ring_buffer.c
@@ -230,6 +230,18 @@ out:
 	return -ENOSPC;
 }
 
+int perf_output_begin_onward(struct perf_output_handle *handle,
+			     struct perf_event *event, unsigned int size)
+{
+	return __perf_output_begin(handle, event, size, false);
+}
+
+int perf_output_begin_backward(struct perf_output_handle *handle,
+			       struct perf_event *event, unsigned int size)
+{
+	return __perf_output_begin(handle, event, size, true);
+}
+
 int perf_output_begin(struct perf_output_handle *handle,
 		      struct perf_event *event, unsigned int size)
 {
-- 
1.8.3.4

  parent reply	other threads:[~2016-01-25 10:00 UTC|newest]

Thread overview: 79+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-01-25  9:55 [GIT PULL 00/54] perf tools: Bugfix, BPF improvements and overwrite ring buffer support Wang Nan
2016-01-25  9:55 ` [PATCH 01/54] perf test: Add libbpf relocation checker Wang Nan
2016-01-26 14:58   ` Arnaldo Carvalho de Melo
2016-01-26 15:07     ` Arnaldo Carvalho de Melo
2016-02-03 10:13   ` [tip:perf/core] " tip-bot for Wang Nan
2016-01-25  9:55 ` [PATCH 02/54] perf bpf: Check relocation target section Wang Nan
2016-02-03 10:14   ` [tip:perf/core] " tip-bot for Wang Nan
2016-01-25  9:55 ` [PATCH 03/54] tools build: Allow subprojects select all feature checkers Wang Nan
2016-02-03 10:14   ` [tip:perf/core] " tip-bot for Wang Nan
2016-01-25  9:55 ` [PATCH 04/54] perf build: Select all feature checkers for feature-dump Wang Nan
2016-02-03 10:14   ` [tip:perf/core] " tip-bot for Wang Nan
2016-01-25  9:55 ` [PATCH 05/54] perf build: Use feature dump file for build-test Wang Nan
2016-01-26 16:59   ` Arnaldo Carvalho de Melo
2016-01-27  2:36     ` Wangnan (F)
2016-01-27 13:54       ` Arnaldo Carvalho de Melo
2016-01-27 11:22     ` [PATCH] tools build: Check basic headers for test-compile feature checker Wang Nan
2016-01-27 13:23       ` Jiri Olsa
2016-01-27 13:55         ` Arnaldo Carvalho de Melo
2016-02-03 10:15       ` [tip:perf/core] " tip-bot for Wang Nan
2016-01-25  9:55 ` [PATCH 06/54] perf test: Check environment before start real BPF test Wang Nan
2016-02-03 10:18   ` [tip:perf/core] " tip-bot for Wang Nan
2016-01-25  9:55 ` [PATCH 07/54] perf tools: Fix symbols searching for offline module in buildid-cache Wang Nan
2016-01-25  9:55 ` [PATCH 08/54] perf test: Improve bp_signal Wang Nan
2016-02-03 10:18   ` [tip:perf/core] " tip-bot for Wang Nan
2016-01-25  9:55 ` [PATCH 09/54] perf tools: Add API to config maps in bpf object Wang Nan
2016-02-03 23:29   ` Arnaldo Carvalho de Melo
2016-02-04 12:59     ` Wangnan (F)
2016-01-25  9:55 ` [PATCH 10/54] perf tools: Enable BPF object configure syntax Wang Nan
2016-01-25  9:55 ` [PATCH 11/54] perf record: Apply config to BPF objects before recording Wang Nan
2016-01-25  9:55 ` [PATCH 12/54] perf tools: Enable passing event to BPF object Wang Nan
2016-01-25  9:56 ` [PATCH 13/54] perf tools: Support perf event alias name Wang Nan
2016-02-03 23:35   ` Arnaldo Carvalho de Melo
2016-01-25  9:56 ` [PATCH 14/54] perf tools: Support setting different slots in a BPF map separately Wang Nan
2016-01-25  9:56 ` [PATCH 15/54] perf tools: Enable indices setting syntax for BPF maps Wang Nan
2016-01-25  9:56 ` [PATCH 16/54] perf tools: Introduce bpf-output event Wang Nan
2016-01-25  9:56 ` [PATCH 17/54] perf data: Support converting data from bpf_perf_event_output() Wang Nan
2016-01-25  9:56 ` [PATCH 18/54] perf core: Introduce new ioctl options to pause and resume ring buffer Wang Nan
2016-01-25  9:56 ` [PATCH 19/54] perf core: Set event's default overflow_handler Wang Nan
2016-01-25  9:56 ` [PATCH 20/54] perf core: Prepare writing into ring buffer from end Wang Nan
2016-01-25  9:56 ` [PATCH 21/54] perf core: Add backward attribute to perf event Wang Nan
2016-01-25  9:56 ` Wang Nan [this message]
2016-01-25  9:56 ` [PATCH 23/54] perf tools: Introduce API to pause ring buffer Wang Nan
2016-01-25  9:56 ` [PATCH 24/54] perf tools: Only validate is_pos for tracking evsels Wang Nan
2016-01-25  9:56 ` [PATCH 25/54] perf tools: Print write_backward value in perf_event_attr__fprintf Wang Nan
2016-01-25  9:56 ` [PATCH 26/54] perf tools: Move timestamp creation to util Wang Nan
2016-02-03 10:18   ` [tip:perf/core] " tip-bot for Wang Nan
2016-01-25  9:56 ` [PATCH 27/54] perf tools: Make ordered_events reusable Wang Nan
2016-01-25  9:56 ` [PATCH 28/54] perf record: Extract synthesize code to record__synthesize() Wang Nan
2016-01-29 20:37   ` Arnaldo Carvalho de Melo
2016-01-25  9:56 ` [PATCH 29/54] perf tools: Add perf_data_file__switch() helper Wang Nan
2016-01-25  9:56 ` [PATCH 30/54] perf record: Turns auxtrace_snapshot_enable into 3 states Wang Nan
2016-01-25  9:56 ` [PATCH 31/54] perf record: Introduce record__finish_output() to finish a perf.data Wang Nan
2016-01-25  9:56 ` [PATCH 32/54] perf record: Use OPT_BOOLEAN_SET for buildid cache related options Wang Nan
2016-02-03 10:19   ` [tip:perf/core] " tip-bot for Wang Nan
2016-01-25  9:56 ` [PATCH 33/54] perf record: Add '--timestamp-filename' option to append timestamp to output filename Wang Nan
2016-01-25  9:56 ` [PATCH 34/54] perf record: Split output into multiple files via '--switch-output' Wang Nan
2016-01-25  9:56 ` [PATCH 35/54] perf record: Force enable --timestamp-filename when --switch-output is provided Wang Nan
2016-01-25  9:56 ` [PATCH 36/54] perf record: Disable buildid cache options by default in switch output mode Wang Nan
2016-01-25  9:56 ` [PATCH 37/54] perf record: Re-synthesize tracking events after output switching Wang Nan
2016-01-25  9:56 ` [PATCH 38/54] perf record: Generate tracking events for process forked by perf Wang Nan
2016-01-25  9:56 ` [PATCH 39/54] perf record: Ensure return non-zero rc when mmap fail Wang Nan
2016-01-25  9:56 ` [PATCH 40/54] perf record: Prevent reading invalid data in record__mmap_read Wang Nan
2016-01-25  9:56 ` [PATCH 41/54] perf tools: Add evlist channel helpers Wang Nan
2016-01-25  9:56 ` [PATCH 42/54] perf tools: Automatically add new channel according to evlist Wang Nan
2016-01-25  9:56 ` [PATCH 43/54] perf tools: Operate multiple channels Wang Nan
2016-01-25  9:56 ` [PATCH 44/54] perf tools: Squash overwrite setting into channel Wang Nan
2016-01-25  9:56 ` [PATCH 45/54] perf record: Don't read from and poll overwrite channel Wang Nan
2016-01-25  9:56 ` [PATCH 46/54] perf record: Don't poll on " Wang Nan
2016-01-25  9:56 ` [PATCH 47/54] perf tools: Detect avalibility of write_backward Wang Nan
2016-01-25  9:56 ` [PATCH 48/54] perf tools: Enable overwrite settings Wang Nan
2016-01-25  9:56 ` [PATCH 49/54] perf tools: Set write_backward attribut bit for overwrite events Wang Nan
2016-01-25  9:56 ` [PATCH 50/54] perf record: Toggle overwrite ring buffer for reading Wang Nan
2016-01-26  8:25   ` Wangnan (F)
2016-01-25  9:56 ` [PATCH 51/54] perf record: Rename variable to make code clear Wang Nan
2016-01-25  9:56 ` [PATCH 52/54] perf record: Read from backward ring buffer Wang Nan
2016-01-25  9:56 ` [PATCH 53/54] perf record: Allow generate tracking events at the end of output Wang Nan
2016-01-25  9:56 ` [PATCH 54/54] perf tools: Don't warn about out of order event if write_backward is used Wang Nan
2016-01-26  9:11 ` [offlist] Re: [GIT PULL 00/54] perf tools: Bugfix, BPF improvements and overwrite ring buffer support Wangnan (F)
2016-01-26 14:11   ` Arnaldo Carvalho de Melo

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