Commit 426d0073 authored by Chris Wilson's avatar Chris Wilson

drm/i915/gt: Always enable busy-stats for execlists

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: default avatarChris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: default avatarTvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200429205446.3259-1-chris@chris-wilson.co.uk
parent be1cb55a
......@@ -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 *
......
......@@ -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);
......
......@@ -531,28 +531,16 @@ 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.
*
......@@ -560,6 +548,13 @@ 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 {
......
......@@ -1199,17 +1199,14 @@ 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)
if (!atomic_add_unless(&engine->stats.active, 1, 0)) {
engine->stats.start = ktime_get();
GEM_BUG_ON(engine->stats.active == 0);
atomic_inc(&engine->stats.active);
}
write_sequnlock_irqrestore(&engine->stats.lock, flags);
}
......@@ -1217,36 +1214,17 @@ 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);
}
......
......@@ -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)
......
......@@ -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);
......
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