gem_stress: Add an option to test handling of signals

As signals cause the syscalls to be interrupted, we often need to clean
up partial state before returning to userspace. Often a source of
unamusing bugs, so encourage gem_stress to provoke them.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

2 files changed, 41 insertions, 0 deletions

diff --git a/tests/gem_stress.c b/tests/gem_stress.c
index 3bc538ab..a4a5edf2 100644
--- a/tests/gem_stress.c
+++ b/tests/gem_stress.c
@@ -51,6 +51,8 @@
 
 #include "gem_stress.h"
 
+#include <signal.h>
+
 #define CMD_POLY_STIPPLE_OFFSET       0x7906
 
 /** TODO:
@@ -100,6 +102,29 @@ struct {
 	unsigned max_failed_reads;
 } stats;
 
+static void signal_helper_process(pid_t pid)
+{
+	/* Interrupt the parent process at 500Hz, just to be annoying */
+	while (1) {
+		usleep(1000 * 1000 / 500);
+		if (kill(pid, SIGUSR1)) /* Parent has died, so must we. */
+			exit(0);
+	}
+}
+
+static pid_t fork_signal_helper(void)
+{
+	pid_t pid;
+
+	pid = fork();
+	if (pid == 0) {
+		signal_helper_process(getppid());
+		return -1;
+	}
+
+	return pid;
+}
+
 static void tile2xy(struct scratch_buf *buf, unsigned tile, unsigned *x, unsigned *y)
 {
 	assert(tile < buf->num_tiles);
@@ -651,6 +676,7 @@ static void parse_options(int argc, char **argv)
 		{"no-hw", 0, 0, 'd'},
 		{"buf-size", 1, 0, 's'},
 		{"gpu-busy-load", 1, 0, 'g'},
+		{"no-signals", 0, 0, 'S'},
 		{"buffer-count", 1, 0, 'c'},
 		{"trace-tile", 1, 0, 't'},
 		{"disable-blt", 0, 0, 'b'},
@@ -671,6 +697,7 @@ static void parse_options(int argc, char **argv)
 
 	options.scratch_buf_size = 256*4096;
 	options.no_hw = 0;
+	options.use_signal_helper = 1;
 	options.gpu_busy_load = 0;
 	options.num_buffers = 0;
 	options.trace_tile = -1;
@@ -692,6 +719,10 @@ static void parse_options(int argc, char **argv)
 			options.no_hw = 1;
 			printf("no-hw debug mode\n");
 			break;
+		case 'S':
+			options.use_signal_helper = 0;
+			printf("disabling that pesky nuisance who keeps interrupting us\n");
+			break;
 		case 's':
 			tmp = atoi(optarg);
 			if (tmp < options.tile_size*8192)
@@ -881,12 +912,18 @@ int main(int argc, char **argv)
 {
 	int i, j;
 	unsigned *current_permutation, *tmp_permutation;
+	pid_t signal_helper = -1;
 
 	drm_fd = drm_open_any();
 	devid = intel_get_drm_devid(drm_fd);
 
 	parse_options(argc, argv);
 
+	/* start our little helper early before too may allocations occur */
+	signal(SIGUSR1, SIG_IGN);
+	if (options.use_signal_helper)
+		signal_helper = fork_signal_helper();
+
 	init();
 
 	check_render_copyfunc();
@@ -935,5 +972,8 @@ int main(int argc, char **argv)
 
 	close(drm_fd);
 
+	if (signal_helper != -1)
+		kill(signal_helper, SIGQUIT);
+
 	return 0;
 }
diff --git a/tests/gem_stress.h b/tests/gem_stress.h
index 759a5296..f44773d6 100644
--- a/tests/gem_stress.h
+++ b/tests/gem_stress.h
@@ -42,6 +42,7 @@ struct option_struct {
     int ducttape;
     int tile_size;
     int check_render_cpyfn;
+    int use_signal_helper;
 };
 
 extern struct option_struct options;