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/* $OpenBSD: sigprof.c,v 1.1 2020/09/16 14:02:24 mpi Exp $ */
/*
* Copyright (c) 2013 Joel Sing <jsing@openbsd.org>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
/*
* Test that profiling signals are delivered to the thread whose execution
* consumed the CPU time and resulted in the profiling timer expiring.
* Inspired by a problem report test case from Russ Cox <rsc@golang.org>.
*/
#include <err.h>
#include <pthread.h>
#include <signal.h>
#include <stdio.h>
#include <string.h>
#define NTHREADS 4
#define NSIGNALS 100
#define NSIGTOTAL (NTHREADS * NSIGNALS)
#define NMINSIG ((NSIGNALS * 75) / 100)
void handler(int);
void *spinloop(void *);
pthread_t threads[NTHREADS + 1];
int sigcount[NTHREADS + 1];
volatile int sigtotal;
volatile int done;
void
handler(int sig)
{
pthread_t self;
int i;
/*
* pthread_self() is not required to be async-signal-safe, however
* the OpenBSD implementation currently is.
*/
self = pthread_self();
for (i = 0; i <= NTHREADS; i++)
if (threads[i] == self)
sigcount[i]++;
if (++sigtotal >= NSIGTOTAL)
done = 1;
}
void *
spinloop(void *arg)
{
while (!done)
;
pthread_exit(NULL);
}
int
main(int argc, char **argv)
{
struct sigaction sa;
struct itimerval it;
int i;
bzero(&sa, sizeof(sa));
sa.sa_handler = handler;
sa.sa_flags = SA_RESTART;
sigfillset(&sa.sa_mask);
sigaction(SIGPROF, &sa, 0);
threads[0] = pthread_self();
for (i = 1; i <= NTHREADS; i++)
if (pthread_create(&threads[i], NULL, spinloop, NULL) != 0)
err(1, "pthread_create");
bzero(&it, sizeof(it));
it.it_interval.tv_usec = 10000;
it.it_value = it.it_interval;
setitimer(ITIMER_PROF, &it, NULL);
for (i = 1; i <= NTHREADS; i++)
if (pthread_join(threads[i], NULL) != 0)
err(1, "pthread_join");
bzero(&it, sizeof(it));
setitimer(ITIMER_PROF, &it, NULL);
fprintf(stderr, "total profiling signals: %d\n", sigtotal);
fprintf(stderr, "minimum signals per thread: %d\n", NMINSIG);
fprintf(stderr, "main thread - %d\n", sigcount[0]);
for (i = 1; i <= NTHREADS; i++)
fprintf(stderr, "thread %d - %d\n", i, sigcount[i]);
if (sigtotal < NSIGTOTAL)
errx(1, "insufficient profiling signals (%d < %d)",
sigtotal, NSIGTOTAL);
/*
* The main thread is effectively sleeping and should have received
* almost no profiling signals. Allow a small tolerance.
*/
if (sigcount[0] > ((NSIGNALS * 10) / 100))
errx(1, "main thread received too many signals (%d)",
sigcount[0]);
/*
* Ensure that the kernel delivered the profiling signals to the
* thread that consumed the CPU time. In an ideal world each thread
* would have received equal CPU time and an equal number of signals.
* In the less than ideal world we'll just settle for a percentage.
*/
for (i = 1; i <= NTHREADS; i++)
if (sigcount[i] < NMINSIG)
errx(1, "thread %d received only %d signals (%d < %d)",
i, sigcount[i], sigcount[i], NMINSIG);
return 0;
}
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