[igt-dev] [PATCH i-g-t] igt/gem_eio: Exercise set-wedging against request submission

[Chris Wilson]

Build up a large stockpile of requests, ~500,000, and feed them into the
system at 20KHz whilst simultaneously triggering set-wedged in order to
try and race i915_gem_set_wedged() against the engine->submit_request()
callback.

v2: Tweak sleep for flushing timer signals.

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala at linux.intel.com>
Acked-by: Antonio Argenziano <antonio.argenziano at intel.com>
---
 tests/gem_eio.c | 111 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 111 insertions(+)

diff --git a/tests/gem_eio.c b/tests/gem_eio.c
index 5faf7502b..f0dda8150 100644
--- a/tests/gem_eio.c
+++ b/tests/gem_eio.c
@@ -34,6 +34,8 @@
 #include <fcntl.h>
 #include <inttypes.h>
 #include <errno.h>
+#include <sched.h>
+#include <signal.h>
 #include <sys/ioctl.h>
 #include <signal.h>
 #include <time.h>
@@ -43,6 +45,7 @@
 #include "igt.h"
 #include "igt_device.h"
 #include "igt_sysfs.h"
+#include "i915/gem_ring.h"
 #include "sw_sync.h"
 
 IGT_TEST_DESCRIPTION("Test that specific ioctls report a wedged GPU (EIO).");
@@ -705,6 +708,111 @@ static void test_reset_stress(int fd, unsigned int flags)
 	gem_context_destroy(fd, ctx0);
 }
 
+static void notify(union sigval arg)
+{
+	sw_sync_timeline_inc(arg.sival_int, 1);
+}
+
+static void test_set_wedged(int fd)
+{
+#define NCTX 4096
+	const uint32_t bbe = MI_BATCH_BUFFER_END;
+	const unsigned int ring_size = gem_measure_ring_inflight(fd, 0, 0) - 1;
+	struct drm_i915_gem_execbuffer2 execbuf;
+	struct drm_i915_gem_exec_object2 obj;
+	int dir = igt_debugfs_dir(fd);
+	struct itimerspec its;
+	struct sigevent sev;
+	uint32_t *contexts;
+	timer_t timer;
+	int timeline;
+	int syncpt;
+
+	igt_require_sw_sync();
+	igt_require(gem_has_contexts(fd));
+
+	contexts = calloc(NCTX, sizeof(*contexts));
+	igt_assert(contexts);
+
+	for (int n = 0; n < NCTX; n++)
+		contexts[n] = context_create_safe(fd);
+
+	memset(&obj, 0, sizeof(obj));
+	obj.handle = gem_create(fd, 4096);
+	gem_write(fd, obj.handle, 0, &bbe, sizeof(bbe));
+
+	memset(&execbuf, 0, sizeof(execbuf));
+	execbuf.buffers_ptr = to_user_pointer(&obj);
+	execbuf.buffer_count = 1;
+	execbuf.flags = I915_EXEC_FENCE_IN;
+
+	for (unsigned int nctx = 1; nctx <= NCTX; nctx <<= 1) {
+		unsigned int nrq = ring_size;
+		if (!gem_has_execlists(fd)) {
+			nrq = (ring_size + nctx - 1) / nctx + 1;
+			nctx = ring_size / nrq + 1;
+		}
+		igt_assert(nrq);
+		igt_assert(nctx);
+
+		timeline = sw_sync_timeline_create();
+
+		/* Build up a large orderly queue of requests */
+		syncpt = 1;
+		for (int m = 0; m < nrq; m++) {
+			for (int n = 0; n < nctx; n++) {
+				execbuf.rsvd1 = contexts[n];
+				execbuf.rsvd2 =
+					sw_sync_timeline_create_fence(timeline, syncpt);
+				gem_execbuf(fd, &execbuf);
+				close(execbuf.rsvd2);
+
+				syncpt++;
+			}
+		}
+		igt_debug("Queued %d requests over %d contexts\n",
+			  syncpt, nctx);
+
+		igt_require(i915_reset_control(false));
+
+		/* Feed each request in at 20KHz */
+		memset(&sev, 0, sizeof(sev));
+		sev.sigev_notify = SIGEV_THREAD;
+		sev.sigev_value.sival_int = timeline;
+		sev.sigev_notify_function = notify;
+		igt_assert(timer_create(CLOCK_MONOTONIC, &sev, &timer) == 0);
+
+		memset(&its, 0, sizeof(its));
+		its.it_interval.tv_sec = 0;
+		its.it_interval.tv_nsec = 5000;
+		its.it_value = its.it_interval;
+		igt_assert(timer_settime(timer, 0, &its, NULL) == 0);
+		usleep(10);
+
+		igt_debug("Triggering wedge\n");
+		igt_sysfs_set(dir, "i915_wedged", "-1");
+
+		igt_debug("Disabling timer\n");
+		timer_delete(timer);
+		usleep(10000);/* timer_delete() doesn't flush pending signals */
+
+		igt_debug("Cleaning up\n");
+		close(timeline);
+
+		sched_yield();
+		igt_assert(!gem_bo_busy(fd, obj.handle));
+
+		igt_assert(i915_reset_control(true));
+		trigger_reset(fd);
+	}
+
+	gem_close(fd, obj.handle);
+	for (int n = 0; n < NCTX; n++)
+		gem_context_destroy(fd, contexts[n]);
+	free(contexts);
+	close(dir);
+}
+
 static int fd = -1;
 
 static void
@@ -795,4 +903,7 @@ igt_main
 			}
 		}
 	}
+
+	igt_subtest("set-wedged-racing")
+		test_set_wedged(fd);
 }
-- 
2.17.1