Add a regression test that ensures profiling signals are delivered to the

thread whose execution consumed the CPU time and resulted in the profiling
timer expiring. This test currently fails and will be fixed shortly.

Feedback from guenther@

3 files changed, 144 insertions, 2 deletions

diff --git a/regress/sys/kern/Makefile b/regress/sys/kern/Makefile
index 65ca6859d5b..77df15b6c47 100644
--- a/regress/sys/kern/Makefile
+++ b/regress/sys/kern/Makefile
@@ -1,4 +1,4 @@
-#	$OpenBSD: Makefile,v 1.60 2013/01/03 17:43:34 bluhm Exp $
+#	$OpenBSD: Makefile,v 1.61 2013/10/07 15:52:17 jsing Exp $
 
 SUBDIR+= __syscall accept dup2 dup2_self exec_self execve exit extent
 SUBDIR+= fchdir
@@ -10,7 +10,7 @@ SUBDIR+= main-thread-exited
 SUBDIR+= mmap mmap2 mmap3 mmap-fail
 #SUBDIR+= mquery
 SUBDIR+= nanosleep noexec pread preadv ptmget pty pwrite pwritev rcvtimeo
-SUBDIR+= rlimit-file signal signal-stress sigsuspend
+SUBDIR+= rlimit-file signal signal-stress sigprof sigsuspend
 SUBDIR+= sosplice
 SUBDIR+= syscall sysvmsg sysvsem
 SUBDIR+= sysvshm unalign unfdpass wait
diff --git a/regress/sys/kern/sigprof/Makefile b/regress/sys/kern/sigprof/Makefile
new file mode 100644
index 00000000000..0062d7e5b66
--- /dev/null
+++ b/regress/sys/kern/sigprof/Makefile
@@ -0,0 +1,10 @@
+#	$OpenBSD: Makefile,v 1.1 2013/10/07 15:52:18 jsing Exp $
+
+PROG=		sigprof
+
+LIBPTHREAD=	/usr/lib/libpthread.a
+
+LDADD+=		-lpthread
+DPADD+=		${LIBPTHREAD}
+
+.include <bsd.regress.mk>
diff --git a/regress/sys/kern/sigprof/sigprof.c b/regress/sys/kern/sigprof/sigprof.c
new file mode 100644
index 00000000000..9848c96580e
--- /dev/null
+++ b/regress/sys/kern/sigprof/sigprof.c
@@ -0,0 +1,132 @@
+/*	$OpenBSD: sigprof.c,v 1.1 2013/10/07 15:52:18 jsing 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;
+}