Messages in this thread | | | Subject | Re: [PATCH 1/1] perf record: We should fork only if a program was specified to run | From | Peter Zijlstra <> | Date | Fri, 18 Dec 2009 22:13:38 +0100 |
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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 <acme@redhat.com> > > > @@ -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!
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