Messages in this thread | | | Date | Wed, 7 May 2014 17:04:04 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCH v3 2/3] perf record: Propagate exit status of a command line workload |
| |
On Wed, Apr 30, 2014 at 09:24:08AM +0900, Namhyung Kim wrote: > Hi Jiri and Peter, > > On Tue, 29 Apr 2014 13:37:47 +0200, Jiri Olsa wrote: > > On Tue, Apr 29, 2014 at 01:19:39PM +0200, Peter Zijlstra wrote: > >> On Tue, Apr 29, 2014 at 12:56:54PM +0200, Jiri Olsa wrote: > >> > > >> > perf_counter tools: Propagate signals properly > >> > commit f7b7c26e01e51fe46097e11f179dc71ce7950084 > >> > Author: Peter Zijlstra <a.p.zijlstra@chello.nl> > >> > Date: Wed Jun 10 15:55:59 2009 +0200 > >> > > >> > but I dont think we need to do that > >> > >> But but but, then you're re-introducing that fail again? That no good. > > FYI, it's already gone with 804f7ac78803 ("perf record: handle death by > SIGTERM"). > > > > > well, I was trying the testcase you mentioned in the changelog > > and it seemed to work for me.. ;-) I guess I was lucky to hit > > the bash time window.. > > > > while :; do perf stat ./foo ; done > > > > so how does this work? bash will kill the loop if perf's wait > > status is WIFSIGNALED? > > I'm not sure but isn't it *bash* to catch signal and terminate the > loop? It seems the wait status of child has no business with the loop > termination. Am I missing something? > > $ cat suicide.c > #include <signal.h> > > int main(void) > { > raise(SIGTERM); > return 0; > } >
SIGTERM isn't the problem. SIGINT is. Typically when you run:
while :; do perf stat ./foo ; done
Its foo that is running, so when you press ^C, you'll SIGINT foo. foo will then exit, perf stat will notice the exit, exit itself and because the loop doesn't look at the return value of perf stat, simply continues.
What I want, and fixed back then, is that if you press ^C foo terminates, perf stat/record/etc. will finish, but then terminate with the same signal. In that case bash finally sees the SIGINT and will in fact terminate the loop.
try:
$ while :; do ./foo /bin/sleep 5 ; done
and try and break out using ^C
--- #include <stdio.h> #include <stdlib.h> #include <unistd.h> #include <signal.h> #include <sys/types.h> #include <sys/wait.h>
int main(int argc, char *argv[], char *envp[]) { pid_t pid = fork(); if (!pid) /* child */ { execve(argv[1], argv+1, envp); perror("execve"); return; }
signal(SIGINT, SIG_IGN); waitpid(pid, NULL, 0); return 0; } [unhandled content-type:application/pgp-signature] | |