igt/gem_exec_nop: Watch inter-ring synchronisation overhead
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
diff --git a/tests/gem_exec_nop.c b/tests/gem_exec_nop.c
index 78dccbb..ee471ac 100644
--- a/tests/gem_exec_nop.c
+++ b/tests/gem_exec_nop.c
@@ -267,6 +267,72 @@
1e6*time, 1e6*min, 1e6*max, 1e6*sum*2);
}
+static void sequential(int fd, uint32_t handle, int timeout)
+{
+ struct drm_i915_gem_execbuffer2 execbuf;
+ struct drm_i915_gem_exec_object2 obj[2];
+ struct timespec start, now, sync;
+ unsigned engines[16];
+ unsigned nengine;
+ unsigned engine;
+ unsigned long count;
+ double time, sum;
+
+ nengine = 0;
+ sum = 0;
+ for_each_engine(fd, engine) {
+ if (ignore_engine(fd, engine))
+ continue;
+
+ time = nop_on_ring(fd, handle, engine, 1, &count) / count;
+ sum += time;
+ igt_debug("%s: %.3fus\n", e__->name, 1e6*time);
+
+ engines[nengine++] = engine;
+ }
+ igt_require(nengine);
+ igt_info("Total (individual) execution latency %.3fus per cycle\n",
+ 1e6*sum);
+
+ memset(obj, 0, sizeof(obj));
+ obj[0].handle = gem_create(fd, 4096);
+ obj[0].flags = EXEC_OBJECT_WRITE;
+ obj[1].handle = handle;
+
+ memset(&execbuf, 0, sizeof(execbuf));
+ execbuf.buffers_ptr = to_user_pointer(obj);
+ execbuf.buffer_count = 2;
+ execbuf.flags |= LOCAL_I915_EXEC_HANDLE_LUT;
+ execbuf.flags |= LOCAL_I915_EXEC_NO_RELOC;
+ igt_require(__gem_execbuf(fd, &execbuf) == 0);
+
+ intel_detect_and_clear_missed_interrupts(fd);
+
+ count = 0;
+ clock_gettime(CLOCK_MONOTONIC, &start);
+ do {
+ for (int loop = 0; loop < 1024; loop++) {
+ for (int n = 0; n < nengine; n++) {
+ execbuf.flags &= ~ENGINE_FLAGS;
+ execbuf.flags |= engines[n];
+ gem_execbuf(fd, &execbuf);
+ }
+ }
+ count += 1024;
+ clock_gettime(CLOCK_MONOTONIC, &now);
+ } while (elapsed(&start, &now) < timeout); /* Hang detection ~120s */
+ gem_sync(fd, handle);
+ clock_gettime(CLOCK_MONOTONIC, &sync);
+ igt_debug("sync time: %.3fus\n", elapsed(&now, &sync)*1e6);
+ igt_assert_eq(intel_detect_and_clear_missed_interrupts(fd), 0);
+
+ time = elapsed(&start, &now) / count;
+ igt_info("Sequential (%d engines): %'lu cycles, average %.3fus per cycle [expected %.3fus]\n",
+ nengine, count, 1e6*time, 1e6*sum);
+
+ gem_close(fd, obj[0].handle);
+}
+
static void print_welcome(int fd)
{
bool active;
@@ -320,6 +386,9 @@
igt_subtest("basic-parallel")
parallel(device, handle, 5);
+ igt_subtest("basic-sequential")
+ sequential(device, handle, 5);
+
for (e = intel_execution_engines; e->name; e++)
igt_subtest_f("%s", e->name)
single(device, handle, e->exec_id | e->flags, e->name);
@@ -330,6 +399,9 @@
igt_subtest("parallel")
parallel(device, handle, 150);
+ igt_subtest("sequential")
+ sequential(device, handle, 150);
+
igt_fixture {
igt_stop_hang_detector();
gem_close(device, handle);