Re: [PATCH v2] perf data: Allow to use stdio functions for pipe mode
From: Arnaldo Carvalho de Melo
Date: Mon Nov 16 2020 - 11:40:07 EST
Em Sat, Nov 14, 2020 at 09:55:34PM +0100, Jiri Olsa escreveu:
> On Fri, Oct 30, 2020 at 02:47:42PM +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@xxxxxxxxxx>
>
> Acked-by: Jiri Olsa <jolsa@xxxxxxxxxx>
Thanks, tested and applied.
- Arnaldo
> thanks,
> jirka
>
> > ---
> > v2: check result of fdopen()
> >
> > tools/perf/builtin-inject.c | 2 ++
> > tools/perf/util/data.c | 41 ++++++++++++++++++++++++++++++++++---
> > tools/perf/util/data.h | 11 +++++++++-
> > tools/perf/util/header.c | 8 ++++----
> > tools/perf/util/session.c | 7 ++++---
> > 5 files changed, 58 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..05bbcb663c41 100644
> > --- a/tools/perf/util/data.c
> > +++ b/tools/perf/util/data.c
> > @@ -174,8 +174,21 @@ 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);
> > +
> > + if (data->file.fptr == NULL) {
> > + data->file.fd = fd;
> > + data->use_stdio = false;
> > + }
> > + } else {
> > + data->file.fd = fd;
> > + }
> > + }
> >
> > return data->is_pipe = is_pipe;
> > }
> > @@ -334,6 +347,9 @@ 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 +369,21 @@ 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 +395,11 @@ 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");
> > --
> > 2.29.1.341.ge80a0c044ae-goog
> >
>
--
- Arnaldo