tests: Add basic gem_sync test

A very basic test of functionality, execute a nop and wait for it to
complete. It should be very effective at stimulating the "missed
interrupt syndrome" on all devices.

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

tests/Makefile.sources

@@ -148,6 +148,7 @@ TESTS_progs = \
 	gem_set_tiling_vs_gtt \
 	gem_set_tiling_vs_pwrite \
 	gem_storedw_loop \
+	gem_sync \
 	gem_threaded_access_tiled \
 	gem_tiled_fence_blits \
 	gem_tiled_pread_basic \

tests/gem_sync.c

@@ -0,0 +1,160 @@
+/*
+ * Copyright © 2016 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#include <time.h>
+
+#include "igt.h"
+
+IGT_TEST_DESCRIPTION("Basic check of ring<->ring write synchronisation.");
+
+/*
+ * Testcase: Basic check of sync
+ *
+ * Extremely efficient at catching missed irqs
+ */
+
+static unsigned intel_detect_and_clear_missed_irq(int fd)
+{
+	unsigned missed = 0;
+	FILE *file;
+
+	gem_quiescent_gpu(fd);
+
+	file = igt_debugfs_fopen("i915_ring_missed_irq", "r");
+	if (file) {
+		igt_assert(fscanf(file, "%x", &missed) == 1);
+		fclose(file);
+	}
+	if (missed) {
+		file = igt_debugfs_fopen("i915_ring_missed_irq", "w");
+		if (file) {
+			fwrite("0\n", 1, 2, file);
+			fclose(file);
+		}
+	}
+
+	return missed;
+}
+
+static double gettime(void)
+{
+	static clockid_t clock = -1;
+	struct timespec ts;
+
+	/* Stay on the same clock for consistency. */
+	if (clock != (clockid_t)-1) {
+		if (clock_gettime(clock, &ts))
+			goto error;
+		goto out;
+	}
+
+#ifdef CLOCK_MONOTONIC_RAW
+	if (!clock_gettime(clock = CLOCK_MONOTONIC_RAW, &ts))
+		goto out;
+#endif
+#ifdef CLOCK_MONOTONIC_COARSE
+	if (!clock_gettime(clock = CLOCK_MONOTONIC_COARSE, &ts))
+		goto out;
+#endif
+	if (!clock_gettime(clock = CLOCK_MONOTONIC, &ts))
+		goto out;
+error:
+	igt_warn("Could not read monotonic time: %s\n",
+			strerror(errno));
+	igt_assert(0);
+	return 0;
+
+out:
+	return ts.tv_sec + 1e-9*ts.tv_nsec;
+}
+
+static int __gem_execbuf(int fd, struct drm_i915_gem_execbuffer2 *eb)
+{
+	int err = 0;
+	if (drmIoctl(fd, DRM_IOCTL_I915_GEM_EXECBUFFER2, eb))
+		err = -errno;
+	return err;
+}
+
+static void
+sync_ring(int fd, int ring, unsigned flags)
+{
+	const uint32_t bbe = MI_BATCH_BUFFER_END;
+	struct drm_i915_gem_execbuffer2 execbuf;
+	struct drm_i915_gem_exec_object2 object;
+	double start, elapsed;
+	unsigned long cycles;
+
+	intel_detect_and_clear_missed_irq(fd); /* clear before we begin */
+
+	memset(&object, 0, sizeof(object));
+	object.handle = gem_create(fd, 4096);
+	gem_write(fd, object.handle, 4096-sizeof(bbe), &bbe, sizeof(bbe));
+
+	memset(&execbuf, 0, sizeof(execbuf));
+	execbuf.buffers_ptr = (uintptr_t)&object;
+	execbuf.buffer_count = 1;
+	execbuf.flags = ring | flags;
+
+	igt_require(__gem_execbuf(fd, &execbuf) == 0);
+
+	srandom(0xdeadbeef);
+
+	start = gettime();
+	cycles = 0;
+	do {
+		gem_execbuf(fd, &execbuf);
+		gem_sync(fd, object.handle);
+		cycles++;
+	} while ((elapsed = gettime() - start) < SLOW_QUICK(10, 1));
+	igt_info("Completed %ld cycles: %.3f us\n", cycles, elapsed*1e6/cycles);
+
+	gem_close(fd, object.handle);
+	igt_assert_eq(intel_detect_and_clear_missed_irq(fd), 0);
+}
+
+igt_main
+{
+	int fd = -1;
+
+	igt_skip_on_simulation();
+
+	igt_fixture
+		fd = drm_open_driver(DRIVER_INTEL);
+
+	igt_subtest("basic-render")
+		sync_ring(fd, I915_EXEC_RENDER, 0);
+	igt_subtest("basic-blt")
+		sync_ring(fd, I915_EXEC_BLT, 0);
+	igt_subtest("bsd")
+		sync_ring(fd, I915_EXEC_BSD, 0);
+	igt_subtest("bsd1")
+		sync_ring(fd, I915_EXEC_BSD, 1<<13 /*I915_EXEC_BSD_RING1*/);
+	igt_subtest("bsd2")
+		sync_ring(fd, I915_EXEC_BSD, 2<<13 /*I915_EXEC_BSD_RING2*/);
+	igt_subtest("vebox")
+		sync_ring(fd, I915_EXEC_VEBOX, 0);
+
+	igt_fixture
+		close(fd);
+}