[Intel-gfx] [PATCH] drm/i915/selftests: Spin on all engines simultaneously

[Vanshidhar Konda]

On Thu, Oct 31, 2019 at 09:23:36PM +0000, Chris Wilson wrote:
>Vanshidhar Konda asked for the simplest test "to verify that the kernel
>can submit and hardware can execute batch buffers on all the command
>streamers in parallel." We have a number of tests in userspace that
>submit load to each engine and verify that it is present, but strictly
>we have no selftest to prove that the kernel can _simultaneously_
>execute on all known engines. (We have tests to demonstrate that we can
>submit to HW in parallel, but we don't insist that they execute in
>parallel.)
>
>Suggested-by: Vanshidhar Konda <vanshidhar.r.konda at intel.com>
>Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
>Cc: Vanshidhar Konda <vanshidhar.r.konda at intel.com>
>Cc: Matthew Auld <matthew.auld at intel.com>
>---
> drivers/gpu/drm/i915/i915_drv.h               |  6 ++
> drivers/gpu/drm/i915/selftests/i915_request.c | 63 +++++++++++++++++++
> 2 files changed, 69 insertions(+)
>
>diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
>index a22d969cb352..0c3ab6020bc6 100644
>--- a/drivers/gpu/drm/i915/i915_drv.h
>+++ b/drivers/gpu/drm/i915/i915_drv.h
>@@ -891,6 +891,10 @@ struct intel_cdclk_state {
> 	u8 voltage_level;
> };
>
>+struct i915_selftest_stash {
>+	atomic_t counter;
>+};
>+
> struct drm_i915_private {
> 	struct drm_device drm;
>
>@@ -1286,6 +1290,8 @@ struct drm_i915_private {
> 	/* Mutex to protect the above hdcp component related values. */
> 	struct mutex hdcp_comp_mutex;
>
>+	I915_SELFTEST_DECLARE(struct i915_selftest_stash selftest;)
>+
> 	/*
> 	 * NOTE: This is the dri1/ums dungeon, don't add stuff here. Your patch
> 	 * will be rejected. Instead look for a better place.
>diff --git a/drivers/gpu/drm/i915/selftests/i915_request.c b/drivers/gpu/drm/i915/selftests/i915_request.c
>index 30ae34f62176..6181b327b4ac 100644
>--- a/drivers/gpu/drm/i915/selftests/i915_request.c
>+++ b/drivers/gpu/drm/i915/selftests/i915_request.c
>@@ -32,6 +32,7 @@
> #include "i915_random.h"
> #include "i915_selftest.h"
> #include "igt_live_test.h"
>+#include "igt_spinner.h"
> #include "lib_sw_fence.h"
>
> #include "mock_drm.h"
>@@ -1115,12 +1116,72 @@ static int __live_parallel_engineN(void *arg)
> 	return 0;
> }
>
>+static int wait_for_all(struct drm_i915_private *i915)
>+{
>+	if (atomic_dec_and_test(&i915->selftest.counter)) {
>+		wake_up_var(&i915->selftest.counter);
>+		return 0;
>+	}
>+
>+	if (wait_var_event_timeout(&i915->selftest.counter,
>+				   !atomic_read(&i915->selftest.counter),
>+				   i915_selftest.timeout_jiffies))
>+		return 0;
>+
>+	return -ETIME;
>+}
>+
>+static int __live_parallel_spin(void *arg)
>+{
>+	struct intel_engine_cs *engine = arg;
>+	struct igt_spinner spin;
>+	struct i915_request *rq;
>+	int err = 0;
>+
>+	/*
>+	 * Create a spinner running for eternity on each engine. If a second
>+	 * spinner is incorrectly placed on the same engine, it will not be
>+	 * able to start in time.
>+	 */
>+
>+	if (igt_spinner_init(&spin, engine->gt))
>+		return -ENOMEM;
>+
>+	rq = igt_spinner_create_request(&spin,
>+					engine->kernel_context,
>+					MI_NOOP); /* no preemption */
>+	if (IS_ERR(rq)) {
>+		err = PTR_ERR(rq);
>+		goto out_spin;
>+	}
>+
>+	i915_request_get(rq);
>+	i915_request_add(rq);
>+	if (igt_wait_for_spinner(&spin, rq)) {
>+		/* Occupy this engine for the whole test */
>+		err = wait_for_all(engine->i915);
>+	} else {
>+		pr_err("Failed to start spinner on %s\n", engine->name);
>+		err = -EINVAL;
>+	}
>+	igt_spinner_end(&spin);
>+
>+	if (err == 0 && i915_request_wait(rq, 0, HZ / 5) < 0)
>+		err = -EIO;
>+	i915_request_put(rq);
>+
>+out_spin:
>+	igt_spinner_fini(&spin);
>+	return err;
>+}
>+
> static int live_parallel_engines(void *arg)
> {
> 	struct drm_i915_private *i915 = arg;
> 	static int (* const func[])(void *arg) = {
> 		__live_parallel_engine1,
> 		__live_parallel_engineN,
>+		__live_parallel_spin,
> 		NULL,
> 	};
> 	const unsigned int nengines = num_uabi_engines(i915);
>@@ -1146,6 +1207,8 @@ static int live_parallel_engines(void *arg)
> 		if (err)
> 			break;
>
>+		atomic_set(&i915->selftest.counter, nengines);
>+
> 		idx = 0;
> 		for_each_uabi_engine(engine, i915) {
> 			tsk[idx] = kthread_run(*fn, engine,
>-- 
>2.24.0.rc2
>

Reviewed-by: Vanshidhar Konda <vanshidhar.r.konda at intel.com>