[PATCH 01/19] drm/i915/gt: Always enable busy-stats for execlists
Chris Wilson
chris at chris-wilson.co.uk
Sat Apr 25 20:22:51 UTC 2020
In the near future, we will utilize the busy-stats on each engine to
approximate the C0 cycles of each, and use that as an input to a manual
RPS mechanism. That entails having busy-stats always enabled and so we
can remove the enable/disable routines and simplify the pmu setup. As a
consequence of always having the stats enabled, we can also show the
current active time via sysfs/engine/xcs/active_time_ns.
Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
---
drivers/gpu/drm/i915/gt/intel_engine.h | 3 -
drivers/gpu/drm/i915/gt/intel_engine_cs.c | 76 +------------------
drivers/gpu/drm/i915/gt/intel_engine_types.h | 29 +++----
drivers/gpu/drm/i915/gt/intel_lrc.c | 44 +++--------
drivers/gpu/drm/i915/gt/sysfs_engines.c | 16 ++++
drivers/gpu/drm/i915/i915_pmu.c | 32 +-------
drivers/gpu/drm/i915/selftests/i915_request.c | 16 +---
7 files changed, 45 insertions(+), 171 deletions(-)
diff --git a/drivers/gpu/drm/i915/gt/intel_engine.h b/drivers/gpu/drm/i915/gt/intel_engine.h
index d9ee64e2ef79..d10e52ff059f 100644
--- a/drivers/gpu/drm/i915/gt/intel_engine.h
+++ b/drivers/gpu/drm/i915/gt/intel_engine.h
@@ -310,9 +310,6 @@ void intel_engine_dump(struct intel_engine_cs *engine,
struct drm_printer *m,
const char *header, ...);
-int intel_enable_engine_stats(struct intel_engine_cs *engine);
-void intel_disable_engine_stats(struct intel_engine_cs *engine);
-
ktime_t intel_engine_get_busy_time(struct intel_engine_cs *engine);
struct i915_request *
diff --git a/drivers/gpu/drm/i915/gt/intel_engine_cs.c b/drivers/gpu/drm/i915/gt/intel_engine_cs.c
index b1f8527f02c8..2c6b8a37c6e2 100644
--- a/drivers/gpu/drm/i915/gt/intel_engine_cs.c
+++ b/drivers/gpu/drm/i915/gt/intel_engine_cs.c
@@ -1589,58 +1589,6 @@ void intel_engine_dump(struct intel_engine_cs *engine,
intel_engine_print_breadcrumbs(engine, m);
}
-/**
- * intel_enable_engine_stats() - Enable engine busy tracking on engine
- * @engine: engine to enable stats collection
- *
- * Start collecting the engine busyness data for @engine.
- *
- * Returns 0 on success or a negative error code.
- */
-int intel_enable_engine_stats(struct intel_engine_cs *engine)
-{
- struct intel_engine_execlists *execlists = &engine->execlists;
- unsigned long flags;
- int err = 0;
-
- if (!intel_engine_supports_stats(engine))
- return -ENODEV;
-
- execlists_active_lock_bh(execlists);
- write_seqlock_irqsave(&engine->stats.lock, flags);
-
- if (unlikely(engine->stats.enabled == ~0)) {
- err = -EBUSY;
- goto unlock;
- }
-
- if (engine->stats.enabled++ == 0) {
- struct i915_request * const *port;
- struct i915_request *rq;
-
- engine->stats.enabled_at = ktime_get();
-
- /* XXX submission method oblivious? */
- for (port = execlists->active; (rq = *port); port++)
- engine->stats.active++;
-
- for (port = execlists->pending; (rq = *port); port++) {
- /* Exclude any contexts already counted in active */
- if (!intel_context_inflight_count(rq->context))
- engine->stats.active++;
- }
-
- if (engine->stats.active)
- engine->stats.start = engine->stats.enabled_at;
- }
-
-unlock:
- write_sequnlock_irqrestore(&engine->stats.lock, flags);
- execlists_active_unlock_bh(execlists);
-
- return err;
-}
-
static ktime_t __intel_engine_get_busy_time(struct intel_engine_cs *engine)
{
ktime_t total = engine->stats.total;
@@ -1649,7 +1597,7 @@ static ktime_t __intel_engine_get_busy_time(struct intel_engine_cs *engine)
* If the engine is executing something at the moment
* add it to the total.
*/
- if (engine->stats.active)
+ if (atomic_read(&engine->stats.active))
total = ktime_add(total,
ktime_sub(ktime_get(), engine->stats.start));
@@ -1675,28 +1623,6 @@ ktime_t intel_engine_get_busy_time(struct intel_engine_cs *engine)
return total;
}
-/**
- * intel_disable_engine_stats() - Disable engine busy tracking on engine
- * @engine: engine to disable stats collection
- *
- * Stops collecting the engine busyness data for @engine.
- */
-void intel_disable_engine_stats(struct intel_engine_cs *engine)
-{
- unsigned long flags;
-
- if (!intel_engine_supports_stats(engine))
- return;
-
- write_seqlock_irqsave(&engine->stats.lock, flags);
- WARN_ON_ONCE(engine->stats.enabled == 0);
- if (--engine->stats.enabled == 0) {
- engine->stats.total = __intel_engine_get_busy_time(engine);
- engine->stats.active = 0;
- }
- write_sequnlock_irqrestore(&engine->stats.lock, flags);
-}
-
static bool match_ring(struct i915_request *rq)
{
u32 ring = ENGINE_READ(rq->engine, RING_START);
diff --git a/drivers/gpu/drm/i915/gt/intel_engine_types.h b/drivers/gpu/drm/i915/gt/intel_engine_types.h
index bf395227c99f..d7250b2d4175 100644
--- a/drivers/gpu/drm/i915/gt/intel_engine_types.h
+++ b/drivers/gpu/drm/i915/gt/intel_engine_types.h
@@ -527,28 +527,16 @@ struct intel_engine_cs {
u32 (*get_cmd_length_mask)(u32 cmd_header);
struct {
- /**
- * @lock: Lock protecting the below fields.
- */
- seqlock_t lock;
- /**
- * @enabled: Reference count indicating number of listeners.
- */
- unsigned int enabled;
/**
* @active: Number of contexts currently scheduled in.
*/
- unsigned int active;
- /**
- * @enabled_at: Timestamp when busy stats were enabled.
- */
- ktime_t enabled_at;
+ atomic_t active;
+
/**
- * @start: Timestamp of the last idle to active transition.
- *
- * Idle is defined as active == 0, active is active > 0.
+ * @lock: Lock protecting the below fields.
*/
- ktime_t start;
+ seqlock_t lock;
+
/**
* @total: Total time this engine was busy.
*
@@ -556,6 +544,13 @@ struct intel_engine_cs {
* where engine is currently busy (active > 0).
*/
ktime_t total;
+
+ /**
+ * @start: Timestamp of the last idle to active transition.
+ *
+ * Idle is defined as active == 0, active is active > 0.
+ */
+ ktime_t start;
} stats;
struct {
diff --git a/drivers/gpu/drm/i915/gt/intel_lrc.c b/drivers/gpu/drm/i915/gt/intel_lrc.c
index c8014c265ffb..6ba476b1b84a 100644
--- a/drivers/gpu/drm/i915/gt/intel_lrc.c
+++ b/drivers/gpu/drm/i915/gt/intel_lrc.c
@@ -1212,17 +1212,14 @@ static void intel_engine_context_in(struct intel_engine_cs *engine)
{
unsigned long flags;
- if (READ_ONCE(engine->stats.enabled) == 0)
+ if (atomic_add_unless(&engine->stats.active, 1, 0))
return;
write_seqlock_irqsave(&engine->stats.lock, flags);
-
- if (engine->stats.enabled > 0) {
- if (engine->stats.active++ == 0)
- engine->stats.start = ktime_get();
- GEM_BUG_ON(engine->stats.active == 0);
+ if (!atomic_add_unless(&engine->stats.active, 1, 0)) {
+ engine->stats.start = ktime_get();
+ atomic_inc(&engine->stats.active);
}
-
write_sequnlock_irqrestore(&engine->stats.lock, flags);
}
@@ -1230,36 +1227,17 @@ static void intel_engine_context_out(struct intel_engine_cs *engine)
{
unsigned long flags;
- if (READ_ONCE(engine->stats.enabled) == 0)
+ GEM_BUG_ON(!atomic_read(&engine->stats.active));
+
+ if (atomic_add_unless(&engine->stats.active, -1, 1))
return;
write_seqlock_irqsave(&engine->stats.lock, flags);
-
- if (engine->stats.enabled > 0) {
- ktime_t last;
-
- if (engine->stats.active && --engine->stats.active == 0) {
- /*
- * Decrement the active context count and in case GPU
- * is now idle add up to the running total.
- */
- last = ktime_sub(ktime_get(), engine->stats.start);
-
- engine->stats.total = ktime_add(engine->stats.total,
- last);
- } else if (engine->stats.active == 0) {
- /*
- * After turning on engine stats, context out might be
- * the first event in which case we account from the
- * time stats gathering was turned on.
- */
- last = ktime_sub(ktime_get(), engine->stats.enabled_at);
-
- engine->stats.total = ktime_add(engine->stats.total,
- last);
- }
+ if (atomic_dec_and_test(&engine->stats.active)) {
+ engine->stats.total =
+ ktime_add(engine->stats.total,
+ ktime_sub(ktime_get(), engine->stats.start));
}
-
write_sequnlock_irqrestore(&engine->stats.lock, flags);
}
diff --git a/drivers/gpu/drm/i915/gt/sysfs_engines.c b/drivers/gpu/drm/i915/gt/sysfs_engines.c
index 8f9b2f33dbaf..14c8345d860e 100644
--- a/drivers/gpu/drm/i915/gt/sysfs_engines.c
+++ b/drivers/gpu/drm/i915/gt/sysfs_engines.c
@@ -57,6 +57,18 @@ mmio_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
static struct kobj_attribute mmio_attr =
__ATTR(mmio_base, 0444, mmio_show, NULL);
+static ssize_t
+active_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
+{
+ struct intel_engine_cs *engine = kobj_to_engine(kobj);
+
+ return sprintf(buf, "%llu\n",
+ ktime_to_ns(intel_engine_get_busy_time(engine)));
+}
+
+static struct kobj_attribute active_attr =
+__ATTR(active_time_ns, 0444, active_show, NULL);
+
static const char * const vcs_caps[] = {
[ilog2(I915_VIDEO_CLASS_CAPABILITY_HEVC)] = "hevc",
[ilog2(I915_VIDEO_AND_ENHANCE_CLASS_CAPABILITY_SFC)] = "sfc",
@@ -425,6 +437,10 @@ void intel_engines_add_sysfs(struct drm_i915_private *i915)
if (sysfs_create_files(kobj, files))
goto err_object;
+ if (intel_engine_supports_stats(engine) &&
+ sysfs_create_file(kobj, &active_attr.attr))
+ goto err_engine;
+
if (intel_engine_has_timeslices(engine) &&
sysfs_create_file(kobj, ×lice_duration_attr.attr))
goto err_engine;
diff --git a/drivers/gpu/drm/i915/i915_pmu.c b/drivers/gpu/drm/i915/i915_pmu.c
index 230e9256ab30..83c6a8ccd2cb 100644
--- a/drivers/gpu/drm/i915/i915_pmu.c
+++ b/drivers/gpu/drm/i915/i915_pmu.c
@@ -439,29 +439,9 @@ static u64 count_interrupts(struct drm_i915_private *i915)
return sum;
}
-static void engine_event_destroy(struct perf_event *event)
-{
- struct drm_i915_private *i915 =
- container_of(event->pmu, typeof(*i915), pmu.base);
- struct intel_engine_cs *engine;
-
- engine = intel_engine_lookup_user(i915,
- engine_event_class(event),
- engine_event_instance(event));
- if (drm_WARN_ON_ONCE(&i915->drm, !engine))
- return;
-
- if (engine_event_sample(event) == I915_SAMPLE_BUSY &&
- intel_engine_supports_stats(engine))
- intel_disable_engine_stats(engine);
-}
-
static void i915_pmu_event_destroy(struct perf_event *event)
{
WARN_ON(event->parent);
-
- if (is_engine_event(event))
- engine_event_destroy(event);
}
static int
@@ -514,23 +494,13 @@ static int engine_event_init(struct perf_event *event)
struct drm_i915_private *i915 =
container_of(event->pmu, typeof(*i915), pmu.base);
struct intel_engine_cs *engine;
- u8 sample;
- int ret;
engine = intel_engine_lookup_user(i915, engine_event_class(event),
engine_event_instance(event));
if (!engine)
return -ENODEV;
- sample = engine_event_sample(event);
- ret = engine_event_status(engine, sample);
- if (ret)
- return ret;
-
- if (sample == I915_SAMPLE_BUSY && intel_engine_supports_stats(engine))
- ret = intel_enable_engine_stats(engine);
-
- return ret;
+ return engine_event_status(engine, engine_event_sample(event));
}
static int i915_pmu_event_init(struct perf_event *event)
diff --git a/drivers/gpu/drm/i915/selftests/i915_request.c b/drivers/gpu/drm/i915/selftests/i915_request.c
index 3b319c0953cb..15b1ca9f7a01 100644
--- a/drivers/gpu/drm/i915/selftests/i915_request.c
+++ b/drivers/gpu/drm/i915/selftests/i915_request.c
@@ -1679,8 +1679,7 @@ static int perf_series_engines(void *arg)
p->engine = ps->ce[idx]->engine;
intel_engine_pm_get(p->engine);
- if (intel_engine_supports_stats(p->engine) &&
- !intel_enable_engine_stats(p->engine))
+ if (intel_engine_supports_stats(p->engine))
p->busy = intel_engine_get_busy_time(p->engine) + 1;
p->runtime = -intel_context_get_total_runtime_ns(ce);
p->time = ktime_get();
@@ -1700,7 +1699,6 @@ static int perf_series_engines(void *arg)
if (p->busy) {
p->busy = ktime_sub(intel_engine_get_busy_time(p->engine),
p->busy - 1);
- intel_disable_engine_stats(p->engine);
}
err = switch_to_kernel_sync(ce, err);
@@ -1762,8 +1760,7 @@ static int p_sync0(void *arg)
}
busy = false;
- if (intel_engine_supports_stats(engine) &&
- !intel_enable_engine_stats(engine)) {
+ if (intel_engine_supports_stats(engine)) {
p->busy = intel_engine_get_busy_time(engine);
busy = true;
}
@@ -1796,7 +1793,6 @@ static int p_sync0(void *arg)
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);
@@ -1830,8 +1826,7 @@ static int p_sync1(void *arg)
}
busy = false;
- if (intel_engine_supports_stats(engine) &&
- !intel_enable_engine_stats(engine)) {
+ if (intel_engine_supports_stats(engine)) {
p->busy = intel_engine_get_busy_time(engine);
busy = true;
}
@@ -1866,7 +1861,6 @@ static int p_sync1(void *arg)
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);
@@ -1899,8 +1893,7 @@ static int p_many(void *arg)
}
busy = false;
- if (intel_engine_supports_stats(engine) &&
- !intel_enable_engine_stats(engine)) {
+ if (intel_engine_supports_stats(engine)) {
p->busy = intel_engine_get_busy_time(engine);
busy = true;
}
@@ -1924,7 +1917,6 @@ static int p_many(void *arg)
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);
--
2.20.1
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