Re: RFC: patch to trigger thread stats output from cyclictest with SIGHUP

Clark Williams
2013-03-12T13:43:21Z

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On Tue, 12 Mar 2013 13:10:43 +0100 (CET)
John Kacur <jkacur@redhat.com> wrote:

>
>
> On Mon, 11 Mar 2013, Clark Williams wrote:
>
> > John,
> >
> > Steven suggested a feature for cyclictest that I'd actually been
> > whining about (internally anyway). During long rteval runs there's
> > really no feedback available if you want to know how the run is
> > progressing. Steven suggested sending SIGHUP and dumping the current
> > state. Below is a patch that seems to work for cyclictest; just
> > wanted to get some feedback on whether this would be acceptable
> > behaviour.
> >
> > Of course if we get this going then we need to figure out how to wire
> > it into rteval as well :).
> >
> > Clark
> >
> >
> > diff --git a/src/cyclictest/cyclictest.c b/src/cyclictest/cyclictest.c
> > index 0a15dcb..51b97cf 100644
> > --- a/src/cyclictest/cyclictest.c
> > +++ b/src/cyclictest/cyclictest.c
> > @@ -199,6 +199,11 @@ static char **traceptr;
> > static int traceopt_count;
> > static int traceopt_size;
> >
> > +static struct thread_param **parameters;
> > +static struct thread_stat **statistics;
> > +
> > +static void print_stat(struct thread_param *par, int index, int verbose);
> > +
> > static int latency_target_fd = -1;
> > static int32_t latency_target_value = 0;
> >
> > @@ -1368,6 +1373,19 @@ static int check_timer(void)
> >
> > static void sighand(int sig)
> > {
> > + if (sig == SIGHUP) {
> > + int i;
> > + int oldquiet = quiet;
> > +
> > + quiet = 0;
> > + printf("#---------------------------\n");
> > + printf("# cyclictest current status:\n");
> > + for (i = 0; i < num_threads; i++)
> > + print_stat(parameters[i], i, 0);
> > + printf("#---------------------------\n");
> > + quiet = oldquiet;
> > + return;
> > + }
> > shutdown = 1;
> > if (refresh_on_max)
> > pthread_cond_signal(&refresh_on_max_cond);
> > @@ -1503,8 +1521,6 @@ int main(int argc, char **argv)
> > sigset_t sigset;
> > int signum = SIGALRM;
> > int mode;
> > - struct thread_param **parameters;
> > - struct thread_stat **statistics;
> > int max_cpus = sysconf(_SC_NPROCESSORS_CONF);
> > int i, ret = -1;
> > int status;
> > @@ -1642,6 +1658,7 @@ int main(int argc, char **argv)
> >
> > signal(SIGINT, sighand);
> > signal(SIGTERM, sighand);
> > + signal(SIGHUP, sighand);
> >
> > parameters = calloc(num_threads, sizeof(struct thread_param *));
> > if (!parameters)
> >
>
> Where's your SOB Clark? I'm assuming that you and not Steve are the
> author. I can add this to my development dir for people to try.
>
> Thanks
>
> John

I haven't even committed this to my tree yet :). I was actually toying
with the idea of having an option to setup a fifo what would allow you
to get the stats without having to screen-scrape stdout. Was thinking
about adding a -F/--fifo option where you tell cyclictest where to put
the fifo:

# cyclictest --numa -p95 -m -F /tmp/cyclictest.fifo

Then you could just cat the fifo and get a snapshot, or your program
could open and read it. Still turning this over in my head though.

Clark