[09/10] drm/i915: Track context current active time
diff mbox series

Message ID 20200318121138.909-10-tvrtko.ursulin@linux.intel.com
State New
Headers show
Series
  • Per client engine busyness
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Commit Message

Tvrtko Ursulin March 18, 2020, 12:11 p.m. UTC
From: Tvrtko Ursulin <tvrtko.ursulin@intel.com>

Track context active (on hardware) status together with the start
timestamp.

This will be used to provide better granularity of context
runtime reporting in conjunction with already tracked pphwsp accumulated
runtime.

The latter is only updated on context save so does not give us visibility
to any currently executing work.

As part of the patch the existing runtime tracking data is moved under the
new ce->stats member and updated under the seqlock. This provides the
ability to atomically read out accumulated plus active runtime.

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
---
 drivers/gpu/drm/i915/gem/i915_gem_context.c   |  3 +-
 drivers/gpu/drm/i915/gt/intel_context.c       | 18 +++++-
 drivers/gpu/drm/i915/gt/intel_context.h       |  6 +-
 drivers/gpu/drm/i915/gt/intel_context_types.h | 24 +++++---
 drivers/gpu/drm/i915/gt/intel_lrc.c           | 55 +++++++++++++++----
 drivers/gpu/drm/i915/gt/selftest_lrc.c        | 10 ++--
 drivers/gpu/drm/i915/i915_drm_client.c        |  2 +-
 drivers/gpu/drm/i915/i915_gpu_error.c         |  4 +-
 8 files changed, 90 insertions(+), 32 deletions(-)

Patch
diff mbox series

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context.c b/drivers/gpu/drm/i915/gem/i915_gem_context.c
index 9654f0ab3f45..8c67a1269142 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_context.c
@@ -266,7 +266,8 @@  static void free_engines_rcu(struct rcu_head *rcu)
 		unsigned int class = ce->engine->uabi_class;
 
 		GEM_BUG_ON(class >= ARRAY_SIZE(ctx->past_runtime));
-		atomic64_add(ce->runtime.total, &ctx->past_runtime[class]);
+		atomic64_add(ce->stats.runtime.total,
+			     &ctx->past_runtime[class]);
 	}
 
 	i915_gem_context_put(ctx);
diff --git a/drivers/gpu/drm/i915/gt/intel_context.c b/drivers/gpu/drm/i915/gt/intel_context.c
index 01474d3a558b..1f371f8b202a 100644
--- a/drivers/gpu/drm/i915/gt/intel_context.c
+++ b/drivers/gpu/drm/i915/gt/intel_context.c
@@ -288,7 +288,7 @@  intel_context_init(struct intel_context *ce,
 	ce->sseu = engine->sseu;
 	ce->ring = __intel_context_ring_size(SZ_4K);
 
-	ewma_runtime_init(&ce->runtime.avg);
+	ewma_runtime_init(&ce->stats.runtime.avg);
 
 	ce->vm = i915_vm_get(engine->gt->vm);
 
@@ -296,6 +296,7 @@  intel_context_init(struct intel_context *ce,
 	INIT_LIST_HEAD(&ce->signals);
 
 	mutex_init(&ce->pin_mutex);
+	seqlock_init(&ce->stats.lock);
 
 	i915_active_init(&ce->active,
 			 __intel_context_active, __intel_context_retire);
@@ -390,6 +391,21 @@  struct i915_request *intel_context_create_request(struct intel_context *ce)
 	return rq;
 }
 
+ktime_t intel_context_get_active_time(struct intel_context *ce)
+{
+	struct intel_context_stats *stats = &ce->stats;
+	unsigned int seq;
+	ktime_t total = 0;
+
+	do {
+		seq = read_seqbegin(&stats->lock);
+		if (stats->active)
+			total = ktime_sub(ktime_get(), stats->start);
+	} while (read_seqretry(&stats->lock, seq));
+
+	return total;
+}
+
 #if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)
 #include "selftest_context.c"
 #endif
diff --git a/drivers/gpu/drm/i915/gt/intel_context.h b/drivers/gpu/drm/i915/gt/intel_context.h
index 18efad255124..1f8b6e0bbfaf 100644
--- a/drivers/gpu/drm/i915/gt/intel_context.h
+++ b/drivers/gpu/drm/i915/gt/intel_context.h
@@ -233,7 +233,7 @@  static inline u64 intel_context_get_total_runtime_ns(struct intel_context *ce)
 	const u32 period =
 		RUNTIME_INFO(ce->engine->i915)->cs_timestamp_period_ns;
 
-	return READ_ONCE(ce->runtime.total) * period;
+	return READ_ONCE(ce->stats.runtime.total) * period;
 }
 
 static inline u64 intel_context_get_avg_runtime_ns(struct intel_context *ce)
@@ -241,7 +241,9 @@  static inline u64 intel_context_get_avg_runtime_ns(struct intel_context *ce)
 	const u32 period =
 		RUNTIME_INFO(ce->engine->i915)->cs_timestamp_period_ns;
 
-	return mul_u32_u32(ewma_runtime_read(&ce->runtime.avg), period);
+	return mul_u32_u32(ewma_runtime_read(&ce->stats.runtime.avg), period);
 }
 
+ktime_t intel_context_get_active_time(struct intel_context *ce);
+
 #endif /* __INTEL_CONTEXT_H__ */
diff --git a/drivers/gpu/drm/i915/gt/intel_context_types.h b/drivers/gpu/drm/i915/gt/intel_context_types.h
index d5925c25f109..fe85a3b0b7f4 100644
--- a/drivers/gpu/drm/i915/gt/intel_context_types.h
+++ b/drivers/gpu/drm/i915/gt/intel_context_types.h
@@ -12,6 +12,7 @@ 
 #include <linux/list.h>
 #include <linux/mutex.h>
 #include <linux/types.h>
+#include <linux/seqlock.h>
 
 #include "i915_active_types.h"
 #include "i915_utils.h"
@@ -72,14 +73,21 @@  struct intel_context {
 	u64 lrc_desc;
 	u32 tag; /* cookie passed to HW to track this context on submission */
 
-	/* Time on GPU as tracked by the hw. */
-	struct {
-		struct ewma_runtime avg;
-		u64 total;
-		u32 last;
-		I915_SELFTEST_DECLARE(u32 num_underflow);
-		I915_SELFTEST_DECLARE(u32 max_underflow);
-	} runtime;
+	/** stats: Context GPU engine busyness tracking. */
+	struct intel_context_stats {
+		seqlock_t lock;
+		bool active;
+		ktime_t start;
+
+		/* Time on GPU as tracked by the hw. */
+		struct {
+			struct ewma_runtime avg;
+			u64 total;
+			u32 last;
+			I915_SELFTEST_DECLARE(u32 num_underflow);
+			I915_SELFTEST_DECLARE(u32 max_underflow);
+		} runtime;
+	} stats;
 
 	unsigned int active_count; /* protected by timeline->mutex */
 
diff --git a/drivers/gpu/drm/i915/gt/intel_lrc.c b/drivers/gpu/drm/i915/gt/intel_lrc.c
index 112531b29f59..6143c6a9dea4 100644
--- a/drivers/gpu/drm/i915/gt/intel_lrc.c
+++ b/drivers/gpu/drm/i915/gt/intel_lrc.c
@@ -1206,35 +1206,61 @@  static u32 intel_context_get_runtime(const struct intel_context *ce)
 	return READ_ONCE(ce->lrc_reg_state[CTX_TIMESTAMP]);
 }
 
-static void st_update_runtime_underflow(struct intel_context *ce, s32 dt)
+static void
+st_update_runtime_underflow(struct intel_context_stats *stats, s32 dt)
 {
 #if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)
-	ce->runtime.num_underflow += dt < 0;
-	ce->runtime.max_underflow = max_t(u32, ce->runtime.max_underflow, -dt);
+	stats->runtime.num_underflow += dt < 0;
+	stats->runtime.max_underflow =
+		max_t(u32, stats->runtime.max_underflow, -dt);
 #endif
 }
 
 static void intel_context_update_runtime(struct intel_context *ce)
 {
+	struct intel_context_stats *stats = &ce->stats;
 	u32 old;
 	s32 dt;
 
 	if (intel_context_is_barrier(ce))
 		return;
 
-	old = ce->runtime.last;
-	ce->runtime.last = intel_context_get_runtime(ce);
-	dt = ce->runtime.last - old;
+	old = stats->runtime.last;
+	stats->runtime.last = intel_context_get_runtime(ce);
+	dt = stats->runtime.last - old;
 
 	if (unlikely(dt <= 0)) {
 		CE_TRACE(ce, "runtime underflow: last=%u, new=%u, delta=%d\n",
-			 old, ce->runtime.last, dt);
-		st_update_runtime_underflow(ce, dt);
+			 old, stats->runtime.last, dt);
+		st_update_runtime_underflow(stats, dt);
 		return;
 	}
 
-	ewma_runtime_add(&ce->runtime.avg, dt);
-	ce->runtime.total += dt;
+	ewma_runtime_add(&stats->runtime.avg, dt);
+	stats->runtime.total += dt;
+}
+
+static void intel_context_stats_start(struct intel_context *ce)
+{
+	struct intel_context_stats *stats = &ce->stats;
+	unsigned long flags;
+
+	write_seqlock_irqsave(&stats->lock, flags);
+	stats->start = ktime_get();
+	stats->active = true;
+	write_sequnlock_irqrestore(&stats->lock, flags);
+}
+
+static void intel_context_stats_stop(struct intel_context *ce)
+{
+	struct intel_context_stats *stats = &ce->stats;
+	unsigned long flags;
+
+	write_seqlock_irqsave(&stats->lock, flags);
+	stats->active = false;
+	stats->start = 0;
+	intel_context_update_runtime(ce);
+	write_sequnlock_irqrestore(&stats->lock, flags);
 }
 
 static inline struct intel_engine_cs *
@@ -1304,7 +1330,7 @@  static inline void
 __execlists_schedule_out(struct i915_request *rq,
 			 struct intel_engine_cs * const engine)
 {
-	struct intel_context * const ce = rq->context;
+	struct intel_context *ce = rq->context;
 
 	/*
 	 * NB process_csb() is not under the engine->active.lock and hence
@@ -1320,8 +1346,8 @@  __execlists_schedule_out(struct i915_request *rq,
 	    i915_request_completed(rq))
 		intel_engine_add_retire(engine, ce->timeline);
 
-	intel_context_update_runtime(ce);
 	intel_engine_context_out(engine);
+	intel_context_stats_stop(ce);
 	execlists_context_status_change(rq, INTEL_CONTEXT_SCHEDULE_OUT);
 	intel_gt_pm_put_async(engine->gt);
 
@@ -1790,6 +1816,11 @@  active_timeslice(const struct intel_engine_cs *engine)
 
 static void set_timeslice(struct intel_engine_cs *engine)
 {
+	struct intel_engine_execlists * const execlists = &engine->execlists;
+
+	if (*execlists->active)
+		intel_context_stats_start((*execlists->active)->context);
+
 	if (!intel_engine_has_timeslices(engine))
 		return;
 
diff --git a/drivers/gpu/drm/i915/gt/selftest_lrc.c b/drivers/gpu/drm/i915/gt/selftest_lrc.c
index 6f06ba750a0a..6a51e7fa03ca 100644
--- a/drivers/gpu/drm/i915/gt/selftest_lrc.c
+++ b/drivers/gpu/drm/i915/gt/selftest_lrc.c
@@ -5479,8 +5479,8 @@  static int __live_pphwsp_runtime(struct intel_engine_cs *engine)
 	if (IS_ERR(ce))
 		return PTR_ERR(ce);
 
-	ce->runtime.num_underflow = 0;
-	ce->runtime.max_underflow = 0;
+	ce->stats.runtime.num_underflow = 0;
+	ce->stats.runtime.max_underflow = 0;
 
 	do {
 		unsigned int loop = 1024;
@@ -5518,11 +5518,11 @@  static int __live_pphwsp_runtime(struct intel_engine_cs *engine)
 		intel_context_get_avg_runtime_ns(ce));
 
 	err = 0;
-	if (ce->runtime.num_underflow) {
+	if (ce->stats.runtime.num_underflow) {
 		pr_err("%s: pphwsp underflow %u time(s), max %u cycles!\n",
 		       engine->name,
-		       ce->runtime.num_underflow,
-		       ce->runtime.max_underflow);
+		       ce->stats.runtime.num_underflow,
+		       ce->stats.runtime.max_underflow);
 		GEM_TRACE_DUMP();
 		err = -EOVERFLOW;
 	}
diff --git a/drivers/gpu/drm/i915/i915_drm_client.c b/drivers/gpu/drm/i915/i915_drm_client.c
index 0a2d933fe83c..485a2b75d3e1 100644
--- a/drivers/gpu/drm/i915/i915_drm_client.c
+++ b/drivers/gpu/drm/i915/i915_drm_client.c
@@ -67,7 +67,7 @@  pphwsp_busy_add(struct i915_gem_context *ctx, unsigned int class)
 
 	for_each_gem_engine(ce, engines, it) {
 		if (ce->engine->uabi_class == class)
-			total += ce->runtime.total;
+			total += ce->stats.runtime.total;
 	}
 
 	return total;
diff --git a/drivers/gpu/drm/i915/i915_gpu_error.c b/drivers/gpu/drm/i915/i915_gpu_error.c
index 653e1bc5050e..ce752572c38f 100644
--- a/drivers/gpu/drm/i915/i915_gpu_error.c
+++ b/drivers/gpu/drm/i915/i915_gpu_error.c
@@ -1267,8 +1267,8 @@  static bool record_context(struct i915_gem_context_coredump *e,
 	e->guilty = atomic_read(&ctx->guilty_count);
 	e->active = atomic_read(&ctx->active_count);
 
-	e->total_runtime = rq->context->runtime.total;
-	e->avg_runtime = ewma_runtime_read(&rq->context->runtime.avg);
+	e->total_runtime = rq->context->stats.runtime.total;
+	e->avg_runtime = ewma_runtime_read(&rq->context->stats.runtime.avg);
 
 	simulated = i915_gem_context_no_error_capture(ctx);