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Subject[PATCH 01/10] perf record: We should fork only if a program was specified to run
Date
From: Arnaldo Carvalho de Melo <acme@redhat.com>

IOW: Now 'perf record -a' works, this was a bug introduced in:

856e96608a72412d319e498a3a7c557571f811bd
"perf record: Properly synchronize child creation"

Also fix the -C usage, i.e. allow for profiling all the tasks in one
CPU.

Reported-by: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Frédéric Weisbecker <fweisbec@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
tools/perf/builtin-record.c | 14 ++++++++------
1 files changed, 8 insertions(+), 6 deletions(-)
diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index 63136d0..2654253 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -402,7 +402,7 @@ static void atexit_header(void)
perf_header__write(&session->header, output, true);
}

-static int __cmd_record(int argc __used, const char **argv)
+static int __cmd_record(int argc, const char **argv)
{
int i, counter;
struct stat st;
@@ -411,6 +411,7 @@ static int __cmd_record(int argc __used, const char **argv)
int err;
unsigned long waking = 0;
int child_ready_pipe[2], go_pipe[2];
+ const bool forks = target_pid == -1 && argc > 0;
char buf;

page_size = sysconf(_SC_PAGE_SIZE);
@@ -422,7 +423,7 @@ static int __cmd_record(int argc __used, const char **argv)
signal(SIGCHLD, sig_handler);
signal(SIGINT, sig_handler);

- if (pipe(child_ready_pipe) < 0 || pipe(go_pipe) < 0) {
+ if (forks && (pipe(child_ready_pipe) < 0 || pipe(go_pipe) < 0)) {
perror("failed to create pipes");
exit(-1);
}
@@ -483,7 +484,7 @@ static int __cmd_record(int argc __used, const char **argv)

atexit(atexit_header);

- if (target_pid == -1) {
+ if (forks) {
pid = fork();
if (pid < 0) {
perror("failed to fork");
@@ -550,7 +551,7 @@ static int __cmd_record(int argc __used, const char **argv)
return err;
}

- if (!system_wide)
+ if (!system_wide && profile_cpu == -1)
event__synthesize_thread(pid, process_synthesized_event,
session);
else
@@ -569,7 +570,8 @@ static int __cmd_record(int argc __used, const char **argv)
/*
* Let the child rip
*/
- close(go_pipe[1]);
+ if (forks)
+ close(go_pipe[1]);

for (;;) {
int hits = samples;
@@ -667,7 +669,7 @@ int cmd_record(int argc, const char **argv, const char *prefix __used)

argc = parse_options(argc, argv, options, record_usage,
PARSE_OPT_STOP_AT_NON_OPTION);
- if (!argc && target_pid == -1 && (!system_wide || profile_cpu == -1))
+ if (!argc && target_pid == -1 && !system_wide && profile_cpu == -1)
usage_with_options(record_usage, options);

symbol__init();
--
1.6.2.5
--
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