[PATCH 11/22] drm/i915/selftests: Add request throughput measurement to perf

Chris Wilson chris at chris-wilson.co.uk
Sun Mar 1 14:48:21 UTC 2020


Under ideal circumstances, the driver should be able to keep the GPU
fully saturated with work. Measure how close to ideal we get under the
harshest of conditions with no user payload.

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
---
 .../drm/i915/selftests/i915_perf_selftests.h  |   1 +
 drivers/gpu/drm/i915/selftests/i915_request.c | 285 +++++++++++++++++-
 2 files changed, 285 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/selftests/i915_perf_selftests.h b/drivers/gpu/drm/i915/selftests/i915_perf_selftests.h
index 3bf7f53e9924..d8da142985eb 100644
--- a/drivers/gpu/drm/i915/selftests/i915_perf_selftests.h
+++ b/drivers/gpu/drm/i915/selftests/i915_perf_selftests.h
@@ -16,5 +16,6 @@
  * Tests are executed in order by igt/i915_selftest
  */
 selftest(engine_cs, intel_engine_cs_perf_selftests)
+selftest(request, i915_request_perf_selftests)
 selftest(blt, i915_gem_object_blt_perf_selftests)
 selftest(region, intel_memory_region_perf_selftests)
diff --git a/drivers/gpu/drm/i915/selftests/i915_request.c b/drivers/gpu/drm/i915/selftests/i915_request.c
index f89d9c42f1fa..d4c088cfe4e1 100644
--- a/drivers/gpu/drm/i915/selftests/i915_request.c
+++ b/drivers/gpu/drm/i915/selftests/i915_request.c
@@ -23,6 +23,7 @@
  */
 
 #include <linux/prime_numbers.h>
+#include <linux/pm_qos.h>
 
 #include "gem/i915_gem_pm.h"
 #include "gem/selftests/mock_context.h"
@@ -1233,7 +1234,7 @@ static int live_parallel_engines(void *arg)
 		struct igt_live_test t;
 		unsigned int idx;
 
-		snprintf(name, sizeof(name), "%pS", fn);
+		snprintf(name, sizeof(name), "%ps", *fn);
 		err = igt_live_test_begin(&t, i915, __func__, name);
 		if (err)
 			break;
@@ -1470,3 +1471,285 @@ int i915_request_live_selftests(struct drm_i915_private *i915)
 
 	return i915_subtests(tests, i915);
 }
+
+struct perf_parallel {
+	struct intel_engine_cs *engine;
+	unsigned long count;
+	ktime_t time;
+	ktime_t busy;
+	u64 runtime;
+};
+
+static int switch_to_kernel_sync(struct intel_context *ce, int err)
+{
+	struct i915_request *rq;
+	struct dma_fence *fence;
+
+	rq = intel_engine_create_kernel_request(ce->engine);
+	if (IS_ERR(rq))
+		return PTR_ERR(rq);
+
+	fence = i915_active_fence_get(&ce->timeline->last_request);
+	if (fence) {
+		i915_request_await_dma_fence(rq, fence);
+		dma_fence_put(fence);
+	}
+
+	rq = i915_request_get(rq);
+	i915_request_add(rq);
+	if (i915_request_wait(rq, 0, HZ / 2) < 0 && !err)
+		err = -ETIME;
+	i915_request_put(rq);
+
+	while (!err && !intel_engine_is_idle(ce->engine))
+		intel_engine_flush_submission(ce->engine);
+
+	return err;
+}
+
+static int perf_sync(void *arg)
+{
+	struct perf_parallel *p = arg;
+	struct intel_engine_cs *engine = p->engine;
+	struct intel_context *ce;
+	IGT_TIMEOUT(end_time);
+	unsigned long count;
+	bool busy;
+	int err = 0;
+
+	ce = intel_context_create(engine);
+	if (IS_ERR(ce))
+		return PTR_ERR(ce);
+
+	err = intel_context_pin(ce);
+	if (err) {
+		intel_context_put(ce);
+		return err;
+	}
+
+	busy = false;
+	if (intel_engine_supports_stats(engine) &&
+	    !intel_enable_engine_stats(engine)) {
+		p->busy = intel_engine_get_busy_time(engine);
+		busy = true;
+	}
+
+	p->time = ktime_get();
+	count = 0;
+	do {
+		struct i915_request *rq;
+
+		rq = i915_request_create(ce);
+		if (IS_ERR(rq)) {
+			err = PTR_ERR(rq);
+			break;
+		}
+
+		i915_request_get(rq);
+		i915_request_add(rq);
+
+		err = 0;
+		if (i915_request_wait(rq, 0, HZ / 5) < 0)
+			err = -ETIME;
+		i915_request_put(rq);
+		if (err)
+			break;
+
+		count++;
+	} while (!__igt_timeout(end_time, NULL));
+	p->time = ktime_sub(ktime_get(), p->time);
+
+	if (busy) {
+		p->busy = ktime_sub(intel_engine_get_busy_time(engine),
+				    p->busy);
+		intel_disable_engine_stats(engine);
+	}
+
+	err = switch_to_kernel_sync(ce, err);
+	p->runtime = intel_context_get_total_runtime_ns(ce);
+	p->count = count;
+
+	intel_context_unpin(ce);
+	intel_context_put(ce);
+	return err;
+}
+
+static int perf_many(void *arg)
+{
+	struct perf_parallel *p = arg;
+	struct intel_engine_cs *engine = p->engine;
+	struct intel_context *ce;
+	IGT_TIMEOUT(end_time);
+	unsigned long count;
+	int err = 0;
+	bool busy;
+
+	ce = intel_context_create(engine);
+	if (IS_ERR(ce))
+		return PTR_ERR(ce);
+
+	err = intel_context_pin(ce);
+	if (err) {
+		intel_context_put(ce);
+		return err;
+	}
+
+	busy = false;
+	if (intel_engine_supports_stats(engine) &&
+	    !intel_enable_engine_stats(engine)) {
+		p->busy = intel_engine_get_busy_time(engine);
+		busy = true;
+	}
+
+	count = 0;
+	p->time = ktime_get();
+	do {
+		struct i915_request *rq;
+
+		rq = i915_request_create(ce);
+		if (IS_ERR(rq)) {
+			err = PTR_ERR(rq);
+			break;
+		}
+
+		i915_request_add(rq);
+		count++;
+	} while (!__igt_timeout(end_time, NULL));
+	p->time = ktime_sub(ktime_get(), p->time);
+
+	if (busy) {
+		p->busy = ktime_sub(intel_engine_get_busy_time(engine),
+				    p->busy);
+		intel_disable_engine_stats(engine);
+	}
+
+	err = switch_to_kernel_sync(ce, err);
+	p->runtime = intel_context_get_total_runtime_ns(ce);
+	p->count = count;
+
+	intel_context_unpin(ce);
+	intel_context_put(ce);
+	return err;
+}
+
+static int perf_parallel_engines(void *arg)
+{
+	struct drm_i915_private *i915 = arg;
+	static int (* const func[])(void *arg) = {
+		perf_sync,
+		perf_many,
+		NULL,
+	};
+	const unsigned int nengines = num_uabi_engines(i915);
+	struct intel_engine_cs *engine;
+	int (* const *fn)(void *arg);
+	struct pm_qos_request *qos;
+	struct {
+		struct perf_parallel p;
+		struct task_struct *tsk;
+	} *engines;
+	int err = 0;
+
+	engines = kcalloc(nengines, sizeof(*engines), GFP_KERNEL);
+	if (!engines)
+		return -ENOMEM;
+
+	qos = kzalloc(sizeof(*qos), GFP_KERNEL);
+	if (qos)
+		pm_qos_add_request(qos, PM_QOS_CPU_DMA_LATENCY, 0);
+
+	for (fn = func; *fn; fn++) {
+		char name[KSYM_NAME_LEN];
+		struct igt_live_test t;
+		unsigned int idx;
+
+		snprintf(name, sizeof(name), "%ps", *fn);
+		err = igt_live_test_begin(&t, i915, __func__, name);
+		if (err)
+			break;
+
+		atomic_set(&i915->selftest.counter, nengines);
+
+		idx = 0;
+		for_each_uabi_engine(engine, i915) {
+			intel_engine_pm_get(engine);
+
+			memset(&engines[idx].p, 0, sizeof(engines[idx].p));
+			engines[idx].p.engine = engine;
+
+			engines[idx].tsk = kthread_run(*fn, &engines[idx].p,
+						       "igt:%s", engine->name);
+			if (IS_ERR(engines[idx].tsk)) {
+				err = PTR_ERR(engines[idx].tsk);
+				intel_engine_pm_put(engine);
+				break;
+			}
+			get_task_struct(engines[idx++].tsk);
+		}
+
+		yield(); /* start all threads before we kthread_stop() */
+
+		idx = 0;
+		for_each_uabi_engine(engine, i915) {
+			int status;
+
+			if (IS_ERR(engines[idx].tsk))
+				break;
+
+			status = kthread_stop(engines[idx].tsk);
+			if (status && !err)
+				err = status;
+
+			intel_engine_pm_put(engine);
+			put_task_struct(engines[idx++].tsk);
+		}
+
+		if (igt_live_test_end(&t))
+			err = -EIO;
+		if (err)
+			break;
+
+		idx = 0;
+		for_each_uabi_engine(engine, i915) {
+			struct perf_parallel *p = &engines[idx].p;
+			u64 busy = 100 * ktime_to_ns(p->busy);
+			u64 dt = ktime_to_ns(p->time);
+			int integer, decimal;
+
+			if (dt) {
+				integer = div64_u64(busy, dt);
+				busy -= integer * dt;
+				decimal = div64_u64(100 * busy, dt);
+			} else {
+				integer = 0;
+				decimal = 0;
+			}
+
+			GEM_BUG_ON(engine != p->engine);
+			pr_info("%s %5s: { count:%lu, busy:%d.%02d%%, runtime:%lldms, walltime:%lldms }\n",
+				name, engine->name, p->count, integer, decimal,
+				div_u64(p->runtime, 1000 * 1000),
+				div_u64(ktime_to_ns(p->time), 1000 * 1000));
+			idx++;
+		}
+	}
+
+	if (qos) {
+		pm_qos_remove_request(qos);
+		kfree(qos);
+	}
+	kfree(engines);
+	return err;
+}
+
+int i915_request_perf_selftests(struct drm_i915_private *i915)
+{
+	static const struct i915_subtest tests[] = {
+		SUBTEST(perf_parallel_engines),
+	};
+
+	if (intel_gt_is_wedged(&i915->gt))
+		return 0;
+
+	return i915_subtests(tests, i915);
+}
-- 
2.25.1



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