[PATCH 20/23] perf util: Save pid-cmdline mapping into tracing header

Arnaldo Carvalho de Melo
2017-01-25T13:54:30Z

From: Namhyung Kim <namhyung.kim@lge.com>

Current trace info data lacks the saved cmdline mapping which is needed
for pevent to find out the comm of a task. Add this and bump up the
version number so that perf can determine its presence when reading.

This is mostly corresponding to trace.dat file version 6, but still
lacks 4 byte of number of cpus, and 10 bytes of type string - and I
think we don't need those anyway.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Tested-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jeremy Eder <jeder@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>,
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Stephane Eranian <eranian@google.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
[ Change version test from == to >= ]
Link: http://lkml.kernel.org/n/tip-vaooqpxsikxbb3359p0corcb@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
tools/perf/util/trace-event-info.c | 33 ++++++++++++++++++++++++++++++++-
tools/perf/util/trace-event-parse.c | 17 +++++++++++++++++
tools/perf/util/trace-event-read.c | 36 ++++++++++++++++++++++++++++++++++--
tools/perf/util/trace-event.h | 1 +
4 files changed, 84 insertions(+), 3 deletions(-)

diff --git a/tools/perf/util/trace-event-info.c b/tools/perf/util/trace-event-info.c
index d995743cb673..ceb0e2720223 100644
--- a/tools/perf/util/trace-event-info.c
+++ b/tools/perf/util/trace-event-info.c
@@ -42,7 +42,7 @@
#include "evsel.h"
#include "debug.h"

-#define VERSION "0.5"
+#define VERSION "0.6"

static int output_fd;

@@ -379,6 +379,34 @@ static int record_ftrace_printk(void)
return err;
}

+static int record_saved_cmdline(void)
+{
+ unsigned int size;
+ char *path;
+ struct stat st;
+ int ret, err = 0;
+
+ path = get_tracing_file("saved_cmdlines");
+ if (!path) {
+ pr_debug("can't get tracing/saved_cmdline");
+ return -ENOMEM;
+ }
+
+ ret = stat(path, &st);
+ if (ret < 0) {
+ /* not found */
+ size = 0;
+ if (write(output_fd, &size, 8) != 8)
+ err = -EIO;
+ goto out;
+ }
+ err = record_file(path, 8);
+
+out:
+ put_tracing_file(path);
+ return err;
+}
+
static void
put_tracepoints_path(struct tracepoint_path *tps)
{
@@ -539,6 +567,9 @@ struct tracing_data *tracing_data_get(struct list_head *pattrs,
if (err)
goto out;
err = record_ftrace_printk();
+ if (err)
+ goto out;
+ err = record_saved_cmdline();

out:
/*
diff --git a/tools/perf/util/trace-event-parse.c b/tools/perf/util/trace-event-parse.c
index 33b52eaa39db..de0078e21408 100644
--- a/tools/perf/util/trace-event-parse.c
+++ b/tools/perf/util/trace-event-parse.c
@@ -160,6 +160,23 @@ void parse_ftrace_printk(struct pevent *pevent,
}
}

+void parse_saved_cmdline(struct pevent *pevent,
+ char *file, unsigned int size __maybe_unused)
+{
+ char *comm;
+ char *line;
+ char *next = NULL;
+ int pid;
+
+ line = strtok_r(file, "\n", &next);
+ while (line) {
+ sscanf(line, "%d %ms", &pid, &comm);
+ pevent_register_comm(pevent, comm, pid);
+ free(comm);
+ line = strtok_r(NULL, "\n", &next);
+ }
+}
+
int parse_ftrace_file(struct pevent *pevent, char *buf, unsigned long size)
{
return pevent_parse_event(pevent, buf, size, "ftrace");
diff --git a/tools/perf/util/trace-event-read.c b/tools/perf/util/trace-event-read.c
index b67a0ccf5ab9..61c7162c31c7 100644
--- a/tools/perf/util/trace-event-read.c
+++ b/tools/perf/util/trace-event-read.c
@@ -341,6 +341,31 @@ static int read_event_files(struct pevent *pevent)
return 0;
}

+static int read_saved_cmdline(struct pevent *pevent)
+{
+ unsigned long long size;
+ char *buf;
+
+ /* it can have 0 size */
+ size = read8(pevent);
+ if (!size)
+ return 0;
+
+ buf = malloc(size + 1);
+ if (buf == NULL)
+ return -1;
+
+ if (do_read(buf, size) < 0) {
+ free(buf);
+ return -1;
+ }
+
+ parse_saved_cmdline(pevent, buf, size);
+
+ free(buf);
+ return 0;
+}
+
ssize_t trace_report(int fd, struct trace_event *tevent, bool __repipe)
{
char buf[BUFSIZ];
@@ -379,10 +404,11 @@ ssize_t trace_report(int fd, struct trace_event *tevent, bool __repipe)
return -1;
if (show_version)
printf("version = %s\n", version);
- free(version);

- if (do_read(buf, 1) < 0)
+ if (do_read(buf, 1) < 0) {
+ free(version);
return -1;
+ }
file_bigendian = buf[0];
host_bigendian = bigendian();

@@ -423,6 +449,11 @@ ssize_t trace_report(int fd, struct trace_event *tevent, bool __repipe)
err = read_ftrace_printk(pevent);
if (err)
goto out;
+ if (atof(version) >= 0.6) {
+ err = read_saved_cmdline(pevent);
+ if (err)
+ goto out;
+ }

size = trace_data_size;
repipe = false;
@@ -438,5 +469,6 @@ ssize_t trace_report(int fd, struct trace_event *tevent, bool __repipe)
out:
if (pevent)
trace_event__cleanup(tevent);
+ free(version);
return size;
}
diff --git a/tools/perf/util/trace-event.h b/tools/perf/util/trace-event.h
index b0af9c81bb0d..1fbc044f9eb0 100644
--- a/tools/perf/util/trace-event.h
+++ b/tools/perf/util/trace-event.h
@@ -42,6 +42,7 @@ raw_field_value(struct event_format *event, const char *name, void *data);

void parse_proc_kallsyms(struct pevent *pevent, char *file, unsigned int size);
void parse_ftrace_printk(struct pevent *pevent, char *file, unsigned int size);
+void parse_saved_cmdline(struct pevent *pevent, char *file, unsigned int size);

ssize_t trace_report(int fd, struct trace_event *tevent, bool repipe);

--
2.9.3