From: Arnaldo Carvalho de Melo <[email protected]>
IOW: Now 'perf record -a' works, this was a bug introduced in:
856e96608a72412d319e498a3a7c557571f811bd
"perf record: Properly synchronize child creation"
Reported-by: Pekka Enberg <[email protected]>
Cc: Frédéric Weisbecker <[email protected]>
Cc: Mike Galbraith <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Paul Mackerras <[email protected]>
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
---
tools/perf/builtin-record.c | 9 +++++----
1 files changed, 5 insertions(+), 4 deletions(-)
diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index 63136d0..90eedd9 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;
@@ -422,7 +422,8 @@ 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 (target_pid == -1 && argc > 0 &&
+ (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 (target_pid == -1 && argc > 0) {
pid = fork();
if (pid < 0) {
perror("failed to fork");
@@ -667,7 +668,7 @@ 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)
usage_with_options(record_usage, options);
symbol__init();
--
1.6.2.5
On Fri, 2009-12-18 at 18:42 -0200, Arnaldo Carvalho de Melo wrote:
> From: Arnaldo Carvalho de Melo <[email protected]>
>
> IOW: Now 'perf record -a' works, this was a bug introduced in:
>
> 856e96608a72412d319e498a3a7c557571f811bd
> "perf record: Properly synchronize child creation"
>
> Reported-by: Pekka Enberg <[email protected]>
> Cc: Frédéric Weisbecker <[email protected]>
> Cc: Mike Galbraith <[email protected]>
> Cc: Peter Zijlstra <[email protected]>
> Cc: Paul Mackerras <[email protected]>
> Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
> ---
> tools/perf/builtin-record.c | 9 +++++----
> 1 files changed, 5 insertions(+), 4 deletions(-)
>
> diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
> index 63136d0..90eedd9 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;
> @@ -422,7 +422,8 @@ 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 (target_pid == -1 && argc > 0 &&
> + (pipe(child_ready_pipe) < 0 || pipe(go_pipe) < 0)) {
> perror("failed to create pipes");
> exit(-1);
> }
Why bother?
> @@ -483,7 +484,7 @@ static int __cmd_record(int argc __used, const char **argv)
>
> atexit(atexit_header);
>
> - if (target_pid == -1) {
> + if (target_pid == -1 && argc > 0) {
> pid = fork();
> if (pid < 0) {
> perror("failed to fork");
I'd write:
target_pid == -1 && !system_wide
> @@ -667,7 +668,7 @@ 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)
> usage_with_options(record_usage, options);
>
> symbol__init();
Right, so I was thinking -C would be enough to also start profiling..
clearly messed up the logic though :/
Em Fri, Dec 18, 2009 at 09:52:41PM +0100, Peter Zijlstra escreveu:
> On Fri, 2009-12-18 at 18:42 -0200, Arnaldo Carvalho de Melo wrote:
> > From: Arnaldo Carvalho de Melo <[email protected]>
> > @@ -422,7 +422,8 @@ 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 (target_pid == -1 && argc > 0 &&
> > + (pipe(child_ready_pipe) < 0 || pipe(go_pipe) < 0)) {
> > perror("failed to create pipes");
> > exit(-1);
> > }
>
> Why bother?
Because we don't need it?
> > @@ -483,7 +484,7 @@ static int __cmd_record(int argc __used, const char **argv)
> >
> > atexit(atexit_header);
> >
> > - if (target_pid == -1) {
> > + if (target_pid == -1 && argc > 0) {
> > pid = fork();
> > if (pid < 0) {
> > perror("failed to fork");
>
> I'd write:
>
> target_pid == -1 && !system_wide
Because we want this to work:
[root@doppio linux-2.6-tip]# perf record -a -f sleep 2
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.243 MB perf.data (~10599 samples) ]
[root@doppio linux-2.6-tip]#
See, no hands mother! I.e. it is system wide, but just for 2 seconds,
its clever, but I like it, and it always worked :-)
> > @@ -667,7 +668,7 @@ 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)
> > usage_with_options(record_usage, options);
> >
> > symbol__init();
>
> Right, so I was thinking -C would be enough to also start profiling..
> clearly messed up the logic though :/
Yeah, it should, meaning "profile everything on CPU N"
- Arnaldo
On Fri, 2009-12-18 at 18:58 -0200, Arnaldo Carvalho de Melo wrote:
> Em Fri, Dec 18, 2009 at 09:52:41PM +0100, Peter Zijlstra escreveu:
> > On Fri, 2009-12-18 at 18:42 -0200, Arnaldo Carvalho de Melo wrote:
> > > From: Arnaldo Carvalho de Melo <[email protected]>
> > > @@ -422,7 +422,8 @@ 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 (target_pid == -1 && argc > 0 &&
> > > + (pipe(child_ready_pipe) < 0 || pipe(go_pipe) < 0)) {
> > > perror("failed to create pipes");
> > > exit(-1);
> > > }
> >
> > Why bother?
>
> Because we don't need it?
Well its a rare error, and the paranoid in me says bailing asap avoids
funny cases later.
> > > @@ -483,7 +484,7 @@ static int __cmd_record(int argc __used, const char **argv)
> > >
> > > atexit(atexit_header);
> > >
> > > - if (target_pid == -1) {
> > > + if (target_pid == -1 && argc > 0) {
> > > pid = fork();
> > > if (pid < 0) {
> > > perror("failed to fork");
> >
> > I'd write:
> >
> > target_pid == -1 && !system_wide
>
> Because we want this to work:
>
> [root@doppio linux-2.6-tip]# perf record -a -f sleep 2
> [ perf record: Woken up 1 times to write data ]
> [ perf record: Captured and wrote 0.243 MB perf.data (~10599 samples) ]
> [root@doppio linux-2.6-tip]#
>
> See, no hands mother! I.e. it is system wide, but just for 2 seconds,
> its clever, but I like it, and it always worked :-)
Ah, right.. yes, totally forgot about that.
> > > @@ -667,7 +668,7 @@ 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)
> > > usage_with_options(record_usage, options);
> > >
> > > symbol__init();
> >
> > Right, so I was thinking -C would be enough to also start profiling..
> > clearly messed up the logic though :/
>
> Yeah, it should, meaning "profile everything on CPU N"
Right, so I tried folding that in and goofed up.
Anyway, patch looks ok, thanks!
On Fri, 2009-12-18 at 18:58 -0200, Arnaldo Carvalho de Melo wrote:
> > > - if (pipe(child_ready_pipe) < 0 || pipe(go_pipe) < 0) {
> > > + if (target_pid == -1 && argc > 0 &&
> > > + (pipe(child_ready_pipe) < 0 || pipe(go_pipe) < 0)) {
> > > perror("failed to create pipes");
> > > exit(-1);
> > > }
Also, there's an unconditional close() a bit further down.
If not for that, I'd have put the whole mkpipe thing in the if
(target_pid == -1) branch.
Maybe I shouldn't have skimped on the extra state for that close
* Peter Zijlstra <[email protected]> wrote:
> > Because we want this to work:
> >
> > [root@doppio linux-2.6-tip]# perf record -a -f sleep 2
> > [ perf record: Woken up 1 times to write data ]
> > [ perf record: Captured and wrote 0.243 MB perf.data (~10599 samples) ]
> > [root@doppio linux-2.6-tip]#
> >
> > See, no hands mother! I.e. it is system wide, but just for 2 seconds,
> > its clever, but I like it, and it always worked :-)
>
> Ah, right.. yes, totally forgot about that.
I use the 'perf record -a -f sleep 1' trick all the time to capture a
system-wide snippet of a particular workload.
Ingo
Arnaldo Carvalho de Melo wrote:
> From: Arnaldo Carvalho de Melo <[email protected]>
>
> IOW: Now 'perf record -a' works, this was a bug introduced in:
>
> 856e96608a72412d319e498a3a7c557571f811bd
> "perf record: Properly synchronize child creation"
>
Sorry, i not noticed this patch and also send a patch to fix this bug,
See:
http://lkml.org/lkml/2009/12/20/7
please ignore my patch.
Thanks,
Xiao