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

Clark Williams
2013-03-11T17:16:44Z

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On Mon, 11 Mar 2013 17:54:05 +0100
David Sommerseth <davids@redhat.com> wrote:

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> On 11/03/13 17:25, Paul Gortmaker wrote:
> > On Mon, Mar 11, 2013 at 12:16 PM, Clark Williams
> > <williams@redhat.com> 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.
> >
> > Is USR1 already in use for something? That would be consistent
> > with how things like dd use USR1 signal - to report interim stats.
> >
> > P.
>
> +1 ... I was just about to say exactly the same.
>
>

Good points. As I recall SIGHUP is usually used to force a re-read of
configs (which doesn't really apply here).

Here's a revised version using SIGUSR1:

diff --git a/src/cyclictest/cyclictest.c b/src/cyclictest/cyclictest.c
index 0a15dcb..be4046f 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 == SIGUSR1) {
+ 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(SIGUSR1, sighand);

parameters = calloc(num_threads, sizeof(struct thread_param *));
if (!parameters)