[PATCH] perf data: Allow to use stdio functions for pipe mode

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* [PATCH] perf data: Allow to use stdio functions for pipe mode
@ 2020-10-28  8:56 Namhyung Kim
  2020-10-28 16:37 ` Ian Rogers
  2020-10-29 11:57 ` Jiri Olsa
  0 siblings, 2 replies; 5+ messages in thread
From: Namhyung Kim @ 2020-10-28  8:56 UTC (permalink / raw)
  To: Arnaldo Carvalho de Melo, Jiri Olsa
  Cc: Ingo Molnar, Peter Zijlstra, Mark Rutland, Alexander Shishkin,
	LKML, Stephane Eranian, Ian Rogers

When perf data is in a pipe, it reads each event separately using
read(2) syscall.  This is a huge performance bottleneck when
processing large data like in perf inject.  Also perf inject needs to
use write(2) syscall for the output.

So convert it to use buffer I/O functions in stdio library for pipe
data.  This makes inject-build-id bench time drops from 20ms to 8ms.

  $ perf bench internals inject-build-id
  # Running 'internals/inject-build-id' benchmark:
    Average build-id injection took: 8.074 msec (+- 0.013 msec)
    Average time per event: 0.792 usec (+- 0.001 usec)
    Average memory usage: 8328 KB (+- 0 KB)
    Average build-id-all injection took: 5.490 msec (+- 0.008 msec)
    Average time per event: 0.538 usec (+- 0.001 usec)
    Average memory usage: 7563 KB (+- 0 KB)

This patch enables it just for perf inject when used with pipe (it's a
default behavior).  Maybe we could do it for perf record and/or report
later..

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
---
 tools/perf/builtin-inject.c |  2 ++
 tools/perf/util/data.c      | 36 +++++++++++++++++++++++++++++++++---
 tools/perf/util/data.h      | 11 ++++++++++-
 tools/perf/util/header.c    |  8 ++++----
 tools/perf/util/session.c   |  7 ++++---
 5 files changed, 53 insertions(+), 11 deletions(-)

diff --git a/tools/perf/builtin-inject.c b/tools/perf/builtin-inject.c
index 452a75fe68e5..14d6c88fed76 100644
--- a/tools/perf/builtin-inject.c
+++ b/tools/perf/builtin-inject.c
@@ -853,10 +853,12 @@ int cmd_inject(int argc, const char **argv)
 		.output = {
 			.path = "-",
 			.mode = PERF_DATA_MODE_WRITE,
+			.use_stdio = true,
 		},
 	};
 	struct perf_data data = {
 		.mode = PERF_DATA_MODE_READ,
+		.use_stdio = true,
 	};
 	int ret;
 
diff --git a/tools/perf/util/data.c b/tools/perf/util/data.c
index c47aa34fdc0a..47b5a4b50ca5 100644
--- a/tools/perf/util/data.c
+++ b/tools/perf/util/data.c
@@ -174,8 +174,16 @@ static bool check_pipe(struct perf_data *data)
 			is_pipe = true;
 	}
 
-	if (is_pipe)
-		data->file.fd = fd;
+	if (is_pipe) {
+		if (data->use_stdio) {
+			const char *mode;
+
+			mode = perf_data__is_read(data) ? "r" : "w";
+			data->file.fptr = fdopen(fd, mode);
+		} else {
+			data->file.fd = fd;
+		}
+	}
 
 	return data->is_pipe = is_pipe;
 }
@@ -334,6 +342,9 @@ int perf_data__open(struct perf_data *data)
 	if (check_pipe(data))
 		return 0;
 
+	/* currently it allows stdio for pipe only */
+	data->use_stdio = false;
+
 	if (!data->path)
 		data->path = "perf.data";
 
@@ -353,7 +364,21 @@ void perf_data__close(struct perf_data *data)
 		perf_data__close_dir(data);
 
 	zfree(&data->file.path);
-	close(data->file.fd);
+
+	if (data->use_stdio)
+		fclose(data->file.fptr);
+	else
+		close(data->file.fd);
+}
+
+ssize_t perf_data__read(struct perf_data *data, void *buf, size_t size)
+{
+	if (data->use_stdio) {
+		if (fread(buf, size, 1, data->file.fptr) == 1)
+			return size;
+		return feof(data->file.fptr) ? 0 : -1;
+	}
+	return readn(data->file.fd, buf, size);
 }
 
 ssize_t perf_data_file__write(struct perf_data_file *file,
@@ -365,6 +390,11 @@ ssize_t perf_data_file__write(struct perf_data_file *file,
 ssize_t perf_data__write(struct perf_data *data,
 			      void *buf, size_t size)
 {
+	if (data->use_stdio) {
+		if (fwrite(buf, size, 1, data->file.fptr) == 1)
+			return size;
+		return -1;
+	}
 	return perf_data_file__write(&data->file, buf, size);
 }
 
diff --git a/tools/perf/util/data.h b/tools/perf/util/data.h
index 75947ef6bc17..c563fcbb0288 100644
--- a/tools/perf/util/data.h
+++ b/tools/perf/util/data.h
@@ -2,6 +2,7 @@
 #ifndef __PERF_DATA_H
 #define __PERF_DATA_H
 
+#include <stdio.h>
 #include <stdbool.h>
 
 enum perf_data_mode {
@@ -16,7 +17,10 @@ enum perf_dir_version {
 
 struct perf_data_file {
 	char		*path;
-	int		 fd;
+	union {
+		int	 fd;
+		FILE	*fptr;
+	};
 	unsigned long	 size;
 };
 
@@ -26,6 +30,7 @@ struct perf_data {
 	bool			 is_pipe;
 	bool			 is_dir;
 	bool			 force;
+	bool			 use_stdio;
 	enum perf_data_mode	 mode;
 
 	struct {
@@ -62,11 +67,15 @@ static inline bool perf_data__is_single_file(struct perf_data *data)
 
 static inline int perf_data__fd(struct perf_data *data)
 {
+	if (data->use_stdio)
+		return fileno(data->file.fptr);
+
 	return data->file.fd;
 }
 
 int perf_data__open(struct perf_data *data);
 void perf_data__close(struct perf_data *data);
+ssize_t perf_data__read(struct perf_data *data, void *buf, size_t size);
 ssize_t perf_data__write(struct perf_data *data,
 			      void *buf, size_t size);
 ssize_t perf_data_file__write(struct perf_data_file *file,
diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
index be850e9f8852..d9a70154426b 100644
--- a/tools/perf/util/header.c
+++ b/tools/perf/util/header.c
@@ -3652,7 +3652,8 @@ static int perf_file_section__process(struct perf_file_section *section,
 }
 
 static int perf_file_header__read_pipe(struct perf_pipe_file_header *header,
-				       struct perf_header *ph, int fd,
+				       struct perf_header *ph,
+				       struct perf_data* data,
 				       bool repipe)
 {
 	struct feat_fd ff = {
@@ -3661,7 +3662,7 @@ static int perf_file_header__read_pipe(struct perf_pipe_file_header *header,
 	};
 	ssize_t ret;
 
-	ret = readn(fd, header, sizeof(*header));
+	ret = perf_data__read(data, header, sizeof(*header));
 	if (ret <= 0)
 		return -1;
 
@@ -3684,8 +3685,7 @@ static int perf_header__read_pipe(struct perf_session *session)
 	struct perf_header *header = &session->header;
 	struct perf_pipe_file_header f_header;
 
-	if (perf_file_header__read_pipe(&f_header, header,
-					perf_data__fd(session->data),
+	if (perf_file_header__read_pipe(&f_header, header, session->data,
 					session->repipe) < 0) {
 		pr_debug("incompatible file format\n");
 		return -EINVAL;
diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
index 7a5f03764702..f901a09a58e4 100644
--- a/tools/perf/util/session.c
+++ b/tools/perf/util/session.c
@@ -1923,7 +1923,6 @@ static int __perf_session__process_pipe_events(struct perf_session *session)
 {
 	struct ordered_events *oe = &session->ordered_events;
 	struct perf_tool *tool = session->tool;
-	int fd = perf_data__fd(session->data);
 	union perf_event *event;
 	uint32_t size, cur_size = 0;
 	void *buf = NULL;
@@ -1943,7 +1942,8 @@ static int __perf_session__process_pipe_events(struct perf_session *session)
 	ordered_events__set_copy_on_queue(oe, true);
 more:
 	event = buf;
-	err = readn(fd, event, sizeof(struct perf_event_header));
+	err = perf_data__read(session->data, event,
+			      sizeof(struct perf_event_header));
 	if (err <= 0) {
 		if (err == 0)
 			goto done;
@@ -1975,7 +1975,8 @@ static int __perf_session__process_pipe_events(struct perf_session *session)
 	p += sizeof(struct perf_event_header);
 
 	if (size - sizeof(struct perf_event_header)) {
-		err = readn(fd, p, size - sizeof(struct perf_event_header));
+		err = perf_data__read(session->data, p,
+				      size - sizeof(struct perf_event_header));
 		if (err <= 0) {
 			if (err == 0) {
 				pr_err("unexpected end of event stream\n");
-- 
2.29.0.rc2.309.g374f81d7ae-goog


^ permalink raw reply related	[flat|nested] 5+ messages in thread

* Re: [PATCH] perf data: Allow to use stdio functions for pipe mode
  2020-10-28  8:56 [PATCH] perf data: Allow to use stdio functions for pipe mode Namhyung Kim
@ 2020-10-28 16:37 ` Ian Rogers
  2020-10-29 11:15   ` Namhyung Kim
  2020-10-29 11:57 ` Jiri Olsa
  1 sibling, 1 reply; 5+ messages in thread
From: Ian Rogers @ 2020-10-28 16:37 UTC (permalink / raw)
  To: Namhyung Kim
  Cc: Arnaldo Carvalho de Melo, Jiri Olsa, Ingo Molnar, Peter Zijlstra,
	Mark Rutland, Alexander Shishkin, LKML, Stephane Eranian

On Wed, Oct 28, 2020 at 1:56 AM Namhyung Kim <namhyung@kernel.org> wrote:
>
> When perf data is in a pipe, it reads each event separately using
> read(2) syscall.  This is a huge performance bottleneck when
> processing large data like in perf inject.  Also perf inject needs to
> use write(2) syscall for the output.
>
> So convert it to use buffer I/O functions in stdio library for pipe
> data.  This makes inject-build-id bench time drops from 20ms to 8ms.

This is great! Reading the numbers below the times are reduced to
67.9% of their previous, this is a little less than 20ms to 8ms so
perhaps check that number.

>   $ perf bench internals inject-build-id
>   # Running 'internals/inject-build-id' benchmark:
>     Average build-id injection took: 8.074 msec (+- 0.013 msec)
>     Average time per event: 0.792 usec (+- 0.001 usec)
>     Average memory usage: 8328 KB (+- 0 KB)
>     Average build-id-all injection took: 5.490 msec (+- 0.008 msec)
>     Average time per event: 0.538 usec (+- 0.001 usec)
>     Average memory usage: 7563 KB (+- 0 KB)
>
> This patch enables it just for perf inject when used with pipe (it's a
> default behavior).  Maybe we could do it for perf record and/or report
> later..

For perf record there is also the async IO used for writing. I like
that this patch is adding the reading to perf_data. Should the async
IO code live in perf_data rather than record? Should async IO be used
for reading in that case? What would be the policy of using stdio,
not-stdio and async IO?

Thanks,
Ian

> Signed-off-by: Namhyung Kim <namhyung@kernel.org>
> ---
>  tools/perf/builtin-inject.c |  2 ++
>  tools/perf/util/data.c      | 36 +++++++++++++++++++++++++++++++++---
>  tools/perf/util/data.h      | 11 ++++++++++-
>  tools/perf/util/header.c    |  8 ++++----
>  tools/perf/util/session.c   |  7 ++++---
>  5 files changed, 53 insertions(+), 11 deletions(-)
>
> diff --git a/tools/perf/builtin-inject.c b/tools/perf/builtin-inject.c
> index 452a75fe68e5..14d6c88fed76 100644
> --- a/tools/perf/builtin-inject.c
> +++ b/tools/perf/builtin-inject.c
> @@ -853,10 +853,12 @@ int cmd_inject(int argc, const char **argv)
>                 .output = {
>                         .path = "-",
>                         .mode = PERF_DATA_MODE_WRITE,
> +                       .use_stdio = true,
>                 },
>         };
>         struct perf_data data = {
>                 .mode = PERF_DATA_MODE_READ,
> +               .use_stdio = true,
>         };
>         int ret;
>
> diff --git a/tools/perf/util/data.c b/tools/perf/util/data.c
> index c47aa34fdc0a..47b5a4b50ca5 100644
> --- a/tools/perf/util/data.c
> +++ b/tools/perf/util/data.c
> @@ -174,8 +174,16 @@ static bool check_pipe(struct perf_data *data)
>                         is_pipe = true;
>         }
>
> -       if (is_pipe)
> -               data->file.fd = fd;
> +       if (is_pipe) {
> +               if (data->use_stdio) {
> +                       const char *mode;
> +
> +                       mode = perf_data__is_read(data) ? "r" : "w";
> +                       data->file.fptr = fdopen(fd, mode);
> +               } else {
> +                       data->file.fd = fd;
> +               }
> +       }
>
>         return data->is_pipe = is_pipe;
>  }
> @@ -334,6 +342,9 @@ int perf_data__open(struct perf_data *data)
>         if (check_pipe(data))
>                 return 0;
>
> +       /* currently it allows stdio for pipe only */
> +       data->use_stdio = false;
> +
>         if (!data->path)
>                 data->path = "perf.data";
>
> @@ -353,7 +364,21 @@ void perf_data__close(struct perf_data *data)
>                 perf_data__close_dir(data);
>
>         zfree(&data->file.path);
> -       close(data->file.fd);
> +
> +       if (data->use_stdio)
> +               fclose(data->file.fptr);
> +       else
> +               close(data->file.fd);
> +}
> +
> +ssize_t perf_data__read(struct perf_data *data, void *buf, size_t size)
> +{
> +       if (data->use_stdio) {
> +               if (fread(buf, size, 1, data->file.fptr) == 1)
> +                       return size;
> +               return feof(data->file.fptr) ? 0 : -1;
> +       }
> +       return readn(data->file.fd, buf, size);
>  }
>
>  ssize_t perf_data_file__write(struct perf_data_file *file,
> @@ -365,6 +390,11 @@ ssize_t perf_data_file__write(struct perf_data_file *file,
>  ssize_t perf_data__write(struct perf_data *data,
>                               void *buf, size_t size)
>  {
> +       if (data->use_stdio) {
> +               if (fwrite(buf, size, 1, data->file.fptr) == 1)
> +                       return size;
> +               return -1;
> +       }
>         return perf_data_file__write(&data->file, buf, size);
>  }
>
> diff --git a/tools/perf/util/data.h b/tools/perf/util/data.h
> index 75947ef6bc17..c563fcbb0288 100644
> --- a/tools/perf/util/data.h
> +++ b/tools/perf/util/data.h
> @@ -2,6 +2,7 @@
>  #ifndef __PERF_DATA_H
>  #define __PERF_DATA_H
>
> +#include <stdio.h>
>  #include <stdbool.h>
>
>  enum perf_data_mode {
> @@ -16,7 +17,10 @@ enum perf_dir_version {
>
>  struct perf_data_file {
>         char            *path;
> -       int              fd;
> +       union {
> +               int      fd;
> +               FILE    *fptr;
> +       };
>         unsigned long    size;
>  };
>
> @@ -26,6 +30,7 @@ struct perf_data {
>         bool                     is_pipe;
>         bool                     is_dir;
>         bool                     force;
> +       bool                     use_stdio;
>         enum perf_data_mode      mode;
>
>         struct {
> @@ -62,11 +67,15 @@ static inline bool perf_data__is_single_file(struct perf_data *data)
>
>  static inline int perf_data__fd(struct perf_data *data)
>  {
> +       if (data->use_stdio)
> +               return fileno(data->file.fptr);
> +
>         return data->file.fd;
>  }
>
>  int perf_data__open(struct perf_data *data);
>  void perf_data__close(struct perf_data *data);
> +ssize_t perf_data__read(struct perf_data *data, void *buf, size_t size);
>  ssize_t perf_data__write(struct perf_data *data,
>                               void *buf, size_t size);
>  ssize_t perf_data_file__write(struct perf_data_file *file,
> diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
> index be850e9f8852..d9a70154426b 100644
> --- a/tools/perf/util/header.c
> +++ b/tools/perf/util/header.c
> @@ -3652,7 +3652,8 @@ static int perf_file_section__process(struct perf_file_section *section,
>  }
>
>  static int perf_file_header__read_pipe(struct perf_pipe_file_header *header,
> -                                      struct perf_header *ph, int fd,
> +                                      struct perf_header *ph,
> +                                      struct perf_data* data,
>                                        bool repipe)
>  {
>         struct feat_fd ff = {
> @@ -3661,7 +3662,7 @@ static int perf_file_header__read_pipe(struct perf_pipe_file_header *header,
>         };
>         ssize_t ret;
>
> -       ret = readn(fd, header, sizeof(*header));
> +       ret = perf_data__read(data, header, sizeof(*header));
>         if (ret <= 0)
>                 return -1;
>
> @@ -3684,8 +3685,7 @@ static int perf_header__read_pipe(struct perf_session *session)
>         struct perf_header *header = &session->header;
>         struct perf_pipe_file_header f_header;
>
> -       if (perf_file_header__read_pipe(&f_header, header,
> -                                       perf_data__fd(session->data),
> +       if (perf_file_header__read_pipe(&f_header, header, session->data,
>                                         session->repipe) < 0) {
>                 pr_debug("incompatible file format\n");
>                 return -EINVAL;
> diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
> index 7a5f03764702..f901a09a58e4 100644
> --- a/tools/perf/util/session.c
> +++ b/tools/perf/util/session.c
> @@ -1923,7 +1923,6 @@ static int __perf_session__process_pipe_events(struct perf_session *session)
>  {
>         struct ordered_events *oe = &session->ordered_events;
>         struct perf_tool *tool = session->tool;
> -       int fd = perf_data__fd(session->data);
>         union perf_event *event;
>         uint32_t size, cur_size = 0;
>         void *buf = NULL;
> @@ -1943,7 +1942,8 @@ static int __perf_session__process_pipe_events(struct perf_session *session)
>         ordered_events__set_copy_on_queue(oe, true);
>  more:
>         event = buf;
> -       err = readn(fd, event, sizeof(struct perf_event_header));
> +       err = perf_data__read(session->data, event,
> +                             sizeof(struct perf_event_header));
>         if (err <= 0) {
>                 if (err == 0)
>                         goto done;
> @@ -1975,7 +1975,8 @@ static int __perf_session__process_pipe_events(struct perf_session *session)
>         p += sizeof(struct perf_event_header);
>
>         if (size - sizeof(struct perf_event_header)) {
> -               err = readn(fd, p, size - sizeof(struct perf_event_header));
> +               err = perf_data__read(session->data, p,
> +                                     size - sizeof(struct perf_event_header));
>                 if (err <= 0) {
>                         if (err == 0) {
>                                 pr_err("unexpected end of event stream\n");
> --
> 2.29.0.rc2.309.g374f81d7ae-goog
>

^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: [PATCH] perf data: Allow to use stdio functions for pipe mode
  2020-10-28 16:37 ` Ian Rogers
@ 2020-10-29 11:15   ` Namhyung Kim
  0 siblings, 0 replies; 5+ messages in thread
From: Namhyung Kim @ 2020-10-29 11:15 UTC (permalink / raw)
  To: Ian Rogers
  Cc: Arnaldo Carvalho de Melo, Jiri Olsa, Ingo Molnar, Peter Zijlstra,
	Mark Rutland, Alexander Shishkin, LKML, Stephane Eranian

Hi Ian,

On Thu, Oct 29, 2020 at 1:37 AM Ian Rogers <irogers@google.com> wrote:
>
> On Wed, Oct 28, 2020 at 1:56 AM Namhyung Kim <namhyung@kernel.org> wrote:
> >
> > When perf data is in a pipe, it reads each event separately using
> > read(2) syscall.  This is a huge performance bottleneck when
> > processing large data like in perf inject.  Also perf inject needs to
> > use write(2) syscall for the output.
> >
> > So convert it to use buffer I/O functions in stdio library for pipe
> > data.  This makes inject-build-id bench time drops from 20ms to 8ms.
>
> This is great! Reading the numbers below the times are reduced to
> 67.9% of their previous, this is a little less than 20ms to 8ms so
> perhaps check that number.

The numbers before this patch:

$ ./perf bench internals inject-build-id
# Running 'internals/inject-build-id' benchmark:
  Average build-id injection took: 20.594 msec (+- 0.034 msec)
  Average time per event: 2.019 usec (+- 0.003 usec)
  Average memory usage: 8319 KB (+- 0 KB)
  Average build-id-all injection took: 19.443 msec (+- 0.177 msec)
  Average time per event: 1.906 usec (+- 0.017 usec)
  Average memory usage: 7490 KB (+- 0 KB)

>
> >   $ perf bench internals inject-build-id
> >   # Running 'internals/inject-build-id' benchmark:
> >     Average build-id injection took: 8.074 msec (+- 0.013 msec)
> >     Average time per event: 0.792 usec (+- 0.001 usec)
> >     Average memory usage: 8328 KB (+- 0 KB)
> >     Average build-id-all injection took: 5.490 msec (+- 0.008 msec)
> >     Average time per event: 0.538 usec (+- 0.001 usec)
> >     Average memory usage: 7563 KB (+- 0 KB)
> >
> > This patch enables it just for perf inject when used with pipe (it's a
> > default behavior).  Maybe we could do it for perf record and/or report
> > later..
>
> For perf record there is also the async IO used for writing. I like
> that this patch is adding the reading to perf_data. Should the async
> IO code live in perf_data rather than record? Should async IO be used
> for reading in that case? What would be the policy of using stdio,
> not-stdio and async IO?

I'm not sure but using async IO for read is meaningless since we cannot
do anything without the data.  The reason I added this was that the pipe
mode does so many small I/O with syscalls.  But perf record will mostly
do large I/O so I don't expect big speedup for that.

Thanks
Namhyung

^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: [PATCH] perf data: Allow to use stdio functions for pipe mode
  2020-10-28  8:56 [PATCH] perf data: Allow to use stdio functions for pipe mode Namhyung Kim
  2020-10-28 16:37 ` Ian Rogers
@ 2020-10-29 11:57 ` Jiri Olsa
  2020-10-30  5:34   ` Namhyung Kim
  1 sibling, 1 reply; 5+ messages in thread
From: Jiri Olsa @ 2020-10-29 11:57 UTC (permalink / raw)
  To: Namhyung Kim
  Cc: Arnaldo Carvalho de Melo, Ingo Molnar, Peter Zijlstra,
	Mark Rutland, Alexander Shishkin, LKML, Stephane Eranian,
	Ian Rogers

On Wed, Oct 28, 2020 at 05:56:32PM +0900, Namhyung Kim wrote:
> When perf data is in a pipe, it reads each event separately using
> read(2) syscall.  This is a huge performance bottleneck when
> processing large data like in perf inject.  Also perf inject needs to
> use write(2) syscall for the output.
> 
> So convert it to use buffer I/O functions in stdio library for pipe
> data.  This makes inject-build-id bench time drops from 20ms to 8ms.
> 
>   $ perf bench internals inject-build-id
>   # Running 'internals/inject-build-id' benchmark:
>     Average build-id injection took: 8.074 msec (+- 0.013 msec)
>     Average time per event: 0.792 usec (+- 0.001 usec)
>     Average memory usage: 8328 KB (+- 0 KB)
>     Average build-id-all injection took: 5.490 msec (+- 0.008 msec)
>     Average time per event: 0.538 usec (+- 0.001 usec)
>     Average memory usage: 7563 KB (+- 0 KB)
> 
> This patch enables it just for perf inject when used with pipe (it's a
> default behavior).  Maybe we could do it for perf record and/or report
> later..
> 
> Signed-off-by: Namhyung Kim <namhyung@kernel.org>
> ---
>  tools/perf/builtin-inject.c |  2 ++
>  tools/perf/util/data.c      | 36 +++++++++++++++++++++++++++++++++---
>  tools/perf/util/data.h      | 11 ++++++++++-
>  tools/perf/util/header.c    |  8 ++++----
>  tools/perf/util/session.c   |  7 ++++---
>  5 files changed, 53 insertions(+), 11 deletions(-)
> 
> diff --git a/tools/perf/builtin-inject.c b/tools/perf/builtin-inject.c
> index 452a75fe68e5..14d6c88fed76 100644
> --- a/tools/perf/builtin-inject.c
> +++ b/tools/perf/builtin-inject.c
> @@ -853,10 +853,12 @@ int cmd_inject(int argc, const char **argv)
>  		.output = {
>  			.path = "-",
>  			.mode = PERF_DATA_MODE_WRITE,
> +			.use_stdio = true,
>  		},
>  	};
>  	struct perf_data data = {
>  		.mode = PERF_DATA_MODE_READ,
> +		.use_stdio = true,
>  	};
>  	int ret;
>  
> diff --git a/tools/perf/util/data.c b/tools/perf/util/data.c
> index c47aa34fdc0a..47b5a4b50ca5 100644
> --- a/tools/perf/util/data.c
> +++ b/tools/perf/util/data.c
> @@ -174,8 +174,16 @@ static bool check_pipe(struct perf_data *data)
>  			is_pipe = true;
>  	}
>  
> -	if (is_pipe)
> -		data->file.fd = fd;
> +	if (is_pipe) {
> +		if (data->use_stdio) {
> +			const char *mode;
> +
> +			mode = perf_data__is_read(data) ? "r" : "w";
> +			data->file.fptr = fdopen(fd, mode);

I guess fdopen should never fail right? but I think we should
add BUG_ON(data->file.fptr == NULL) or something

other than this the change looks good, I can see the speedup
in bench as well

jirka


^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: [PATCH] perf data: Allow to use stdio functions for pipe mode
  2020-10-29 11:57 ` Jiri Olsa
@ 2020-10-30  5:34   ` Namhyung Kim
  0 siblings, 0 replies; 5+ messages in thread
From: Namhyung Kim @ 2020-10-30  5:34 UTC (permalink / raw)
  To: Jiri Olsa
  Cc: Arnaldo Carvalho de Melo, Ingo Molnar, Peter Zijlstra,
	Mark Rutland, Alexander Shishkin, LKML, Stephane Eranian,
	Ian Rogers

Hi Jiri,

On Thu, Oct 29, 2020 at 8:57 PM Jiri Olsa <jolsa@redhat.com> wrote:
>
> On Wed, Oct 28, 2020 at 05:56:32PM +0900, Namhyung Kim wrote:
> > When perf data is in a pipe, it reads each event separately using
> > read(2) syscall.  This is a huge performance bottleneck when
> > processing large data like in perf inject.  Also perf inject needs to
> > use write(2) syscall for the output.
> >
> > So convert it to use buffer I/O functions in stdio library for pipe
> > data.  This makes inject-build-id bench time drops from 20ms to 8ms.
> >
> >   $ perf bench internals inject-build-id
> >   # Running 'internals/inject-build-id' benchmark:
> >     Average build-id injection took: 8.074 msec (+- 0.013 msec)
> >     Average time per event: 0.792 usec (+- 0.001 usec)
> >     Average memory usage: 8328 KB (+- 0 KB)
> >     Average build-id-all injection took: 5.490 msec (+- 0.008 msec)
> >     Average time per event: 0.538 usec (+- 0.001 usec)
> >     Average memory usage: 7563 KB (+- 0 KB)
> >
> > This patch enables it just for perf inject when used with pipe (it's a
> > default behavior).  Maybe we could do it for perf record and/or report
> > later..
> >
> > Signed-off-by: Namhyung Kim <namhyung@kernel.org>
> > ---
> >  tools/perf/builtin-inject.c |  2 ++
> >  tools/perf/util/data.c      | 36 +++++++++++++++++++++++++++++++++---
> >  tools/perf/util/data.h      | 11 ++++++++++-
> >  tools/perf/util/header.c    |  8 ++++----
> >  tools/perf/util/session.c   |  7 ++++---
> >  5 files changed, 53 insertions(+), 11 deletions(-)
> >
> > diff --git a/tools/perf/builtin-inject.c b/tools/perf/builtin-inject.c
> > index 452a75fe68e5..14d6c88fed76 100644
> > --- a/tools/perf/builtin-inject.c
> > +++ b/tools/perf/builtin-inject.c
> > @@ -853,10 +853,12 @@ int cmd_inject(int argc, const char **argv)
> >               .output = {
> >                       .path = "-",
> >                       .mode = PERF_DATA_MODE_WRITE,
> > +                     .use_stdio = true,
> >               },
> >       };
> >       struct perf_data data = {
> >               .mode = PERF_DATA_MODE_READ,
> > +             .use_stdio = true,
> >       };
> >       int ret;
> >
> > diff --git a/tools/perf/util/data.c b/tools/perf/util/data.c
> > index c47aa34fdc0a..47b5a4b50ca5 100644
> > --- a/tools/perf/util/data.c
> > +++ b/tools/perf/util/data.c
> > @@ -174,8 +174,16 @@ static bool check_pipe(struct perf_data *data)
> >                       is_pipe = true;
> >       }
> >
> > -     if (is_pipe)
> > -             data->file.fd = fd;
> > +     if (is_pipe) {
> > +             if (data->use_stdio) {
> > +                     const char *mode;
> > +
> > +                     mode = perf_data__is_read(data) ? "r" : "w";
> > +                     data->file.fptr = fdopen(fd, mode);
>
> I guess fdopen should never fail right? but I think we should
> add BUG_ON(data->file.fptr == NULL) or something

The man page says it may fail when mode is invalid or malloc
failed internally.  Will add the check.

>
> other than this the change looks good, I can see the speedup
> in bench as well

Thanks!
Namhyung

^ permalink raw reply	[flat|nested] 5+ messages in thread

end of thread, other threads:[~2020-10-30  5:34 UTC | newest]

Thread overview: 5+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2020-10-28  8:56 [PATCH] perf data: Allow to use stdio functions for pipe mode Namhyung Kim
2020-10-28 16:37 ` Ian Rogers
2020-10-29 11:15   ` Namhyung Kim
2020-10-29 11:57 ` Jiri Olsa
2020-10-30  5:34   ` Namhyung Kim

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