[Intel-gfx] [PATCH 9/9] drm/i915/pmu: Enable legacy PMU events for MTL

Umesh Nerlige Ramappa umesh.nerlige.ramappa at intel.com
Thu Mar 30 18:31:53 UTC 2023


+ Joonas for comments on this

On Thu, Mar 30, 2023 at 02:38:03PM +0100, Tvrtko Ursulin wrote:
>
>On 30/03/2023 01:41, Umesh Nerlige Ramappa wrote:
>>MTL introduces separate GTs for render and media. This complicates the
>>definition of frequency and rc6 counters for the GPU as a whole since
>>each GT has an independent counter. The best way to support this change
>>is to deprecate the GPU-specific counters and create GT-specific
>>counters, however that just breaks ABI. Since perf tools and scripts may
>>be decentralized with probably many users, it's hard to deprecate the
>>legacy counters and have all the users on board with that.
>>
>>Re-introduce the legacy counters and support them as min/max of
>>GT-specific counters as necessary to ensure backwards compatibility.
>>
>>I915_PMU_ACTUAL_FREQUENCY - will show max of GT-specific counters
>>I915_PMU_REQUESTED_FREQUENCY - will show max of GT-specific counters
>>I915_PMU_INTERRUPTS - no changes since it is GPU specific on all platforms
>>I915_PMU_RC6_RESIDENCY - will show min of GT-specific counters
>>I915_PMU_SOFTWARE_GT_AWAKE_TIME - will show max of GT-specific counters
>
>IMO max/min games are _very_ low value and probably just confusing.

By value, do you mean ROI or actually that the values would be 
incorrect?

>
>I am not convinced we need to burden the kernel with this. New 
>platform, new counters.. userspace can just deal with it.

I agree and would prefer to drop this patch. There are some counter 
arguments, I have added Joonas here for comments.

1) an app/script hard-coded with the legacy events would be used on a 
new platform and fail and we should maintain backwards compatibility.

2) the sysfs attributes for rc6/frequency have already adopted an 
aggregate vs gt0/gt1 approach to address that and pmu should have a 
similar solution (or rather, PMU and the sysfs approaches should match 
based on whatever is the approach)

Regards,
Umesh

>
>In intel_gpu_top we can do the smarts in maybe default aggregated view 
>(piggy back/extend on engines aggregation via command line '-p' or '1' 
>at runtime). But then it's not min/max but probably normalized by 
>number of gts.
>
>Regards,
>
>Tvrtko
>
>>
>>Note:
>>- For deeper debugging of performance issues, tools must be upgraded to
>>   read the GT-specific counters.
>>- This patch deserves to be separate from the other PMU features so that
>>   it can be easily dropped if legacy events are ever deprecated.
>>- Internal implementation relies on creating an extra entry in the
>>   arrays used for GT specific counters. Index 0 is empty.
>>   Index 1 through N are mapped to GTs 0 through N - 1.
>>- User interface will use GT numbers indexed from 0 to specify the GT of
>>   interest.
>>
>>Signed-off-by: Umesh Nerlige Ramappa <umesh.nerlige.ramappa at intel.com>
>>---
>>  drivers/gpu/drm/i915/i915_pmu.c | 134 +++++++++++++++++++++++++++-----
>>  drivers/gpu/drm/i915/i915_pmu.h |   2 +-
>>  include/uapi/drm/i915_drm.h     |  14 ++--
>>  3 files changed, 125 insertions(+), 25 deletions(-)
>>
>>diff --git a/drivers/gpu/drm/i915/i915_pmu.c b/drivers/gpu/drm/i915/i915_pmu.c
>>index 9bd9605d2662..0dc7711c3b4b 100644
>>--- a/drivers/gpu/drm/i915/i915_pmu.c
>>+++ b/drivers/gpu/drm/i915/i915_pmu.c
>>@@ -221,7 +221,7 @@ add_sample_mult(struct i915_pmu *pmu, unsigned int gt_id, int sample, u32 val,
>>  static u64 get_rc6(struct intel_gt *gt)
>>  {
>>  	struct drm_i915_private *i915 = gt->i915;
>>-	const unsigned int gt_id = gt->info.id;
>>+	const unsigned int gt_id = gt->info.id + 1;
>>  	struct i915_pmu *pmu = &i915->pmu;
>>  	unsigned long flags;
>>  	bool awake = false;
>>@@ -267,24 +267,26 @@ static void init_rc6(struct i915_pmu *pmu)
>>  	for_each_gt(gt, i915, i) {
>>  		intel_wakeref_t wakeref;
>>+		const unsigned int gt_id = i + 1;
>>  		with_intel_runtime_pm(gt->uncore->rpm, wakeref) {
>>  			u64 val = __get_rc6(gt);
>>-			store_sample(pmu, i, __I915_SAMPLE_RC6, val);
>>-			store_sample(pmu, i, __I915_SAMPLE_RC6_LAST_REPORTED,
>>+			store_sample(pmu, gt_id, __I915_SAMPLE_RC6, val);
>>+			store_sample(pmu, gt_id, __I915_SAMPLE_RC6_LAST_REPORTED,
>>  				     val);
>>-			pmu->sleep_last[i] = ktime_get_raw();
>>+			pmu->sleep_last[gt_id] = ktime_get_raw();
>>  		}
>>  	}
>>  }
>>  static void park_rc6(struct intel_gt *gt)
>>  {
>>+	const unsigned int gt_id = gt->info.id + 1;
>>  	struct i915_pmu *pmu = &gt->i915->pmu;
>>-	store_sample(pmu, gt->info.id, __I915_SAMPLE_RC6, __get_rc6(gt));
>>-	pmu->sleep_last[gt->info.id] = ktime_get_raw();
>>+	store_sample(pmu, gt_id, __I915_SAMPLE_RC6, __get_rc6(gt));
>>+	pmu->sleep_last[gt_id] = ktime_get_raw();
>>  }
>>  static void __i915_pmu_maybe_start_timer(struct i915_pmu *pmu)
>>@@ -436,18 +438,18 @@ static void
>>  frequency_sample(struct intel_gt *gt, unsigned int period_ns)
>>  {
>>  	struct drm_i915_private *i915 = gt->i915;
>>-	const unsigned int gt_id = gt->info.id;
>>+	const unsigned int gt_id = gt->info.id + 1;
>>  	struct i915_pmu *pmu = &i915->pmu;
>>  	struct intel_rps *rps = &gt->rps;
>>-	if (!frequency_sampling_enabled(pmu, gt_id))
>>+	if (!frequency_sampling_enabled(pmu, gt->info.id))
>>  		return;
>>  	/* Report 0/0 (actual/requested) frequency while parked. */
>>  	if (!intel_gt_pm_get_if_awake(gt))
>>  		return;
>>-	if (pmu->enable & config_mask(__I915_PMU_ACTUAL_FREQUENCY(gt_id))) {
>>+	if (pmu->enable & config_mask(__I915_PMU_ACTUAL_FREQUENCY(gt->info.id))) {
>>  		u32 val;
>>  		/*
>>@@ -467,7 +469,7 @@ frequency_sample(struct intel_gt *gt, unsigned int period_ns)
>>  				val, period_ns / 1000);
>>  	}
>>-	if (pmu->enable & config_mask(__I915_PMU_REQUESTED_FREQUENCY(gt_id))) {
>>+	if (pmu->enable & config_mask(__I915_PMU_REQUESTED_FREQUENCY(gt->info.id))) {
>>  		add_sample_mult(pmu, gt_id, __I915_SAMPLE_FREQ_REQ,
>>  				intel_rps_get_requested_frequency(rps),
>>  				period_ns / 1000);
>>@@ -545,14 +547,15 @@ engine_event_status(struct intel_engine_cs *engine,
>>  static int
>>  config_status(struct drm_i915_private *i915, u64 config)
>>  {
>>-	struct intel_gt *gt = to_gt(i915);
>>-
>>  	unsigned int gt_id = config_gt_id(config);
>>-	unsigned int max_gt_id = HAS_EXTRA_GT_LIST(i915) ? 1 : 0;
>>+	unsigned int max_gt_id = HAS_EXTRA_GT_LIST(i915) ? 2 : 1;
>>+	struct intel_gt *gt;
>>  	if (gt_id > max_gt_id)
>>  		return -ENOENT;
>>+	gt = !gt_id ? to_gt(i915) : i915->gt[gt_id - 1];
>>+
>>  	switch (config_counter(config)) {
>>  	case I915_PMU_ACTUAL_FREQUENCY:
>>  		if (IS_VALLEYVIEW(i915) || IS_CHERRYVIEW(i915))
>>@@ -673,23 +676,58 @@ static u64 __i915_pmu_event_read_other(struct perf_event *event)
>>  	const unsigned int gt_id = config_gt_id(event->attr.config);
>>  	const u64 config = config_counter(event->attr.config);
>>  	struct i915_pmu *pmu = &i915->pmu;
>>+	struct intel_gt *gt;
>>  	u64 val = 0;
>>+	int i;
>>  	switch (config) {
>>  	case I915_PMU_ACTUAL_FREQUENCY:
>>-		val = read_sample_us(pmu, gt_id, __I915_SAMPLE_FREQ_ACT);
>>+		if (gt_id)
>>+			return read_sample_us(pmu, gt_id, __I915_SAMPLE_FREQ_ACT);
>>+
>>+		if (!HAS_EXTRA_GT_LIST(i915))
>>+			return read_sample_us(pmu, 1, __I915_SAMPLE_FREQ_ACT);
>>+
>>+		for_each_gt(gt, i915, i)
>>+			val = max(val, read_sample_us(pmu, i + 1, __I915_SAMPLE_FREQ_ACT));
>>+
>>  		break;
>>  	case I915_PMU_REQUESTED_FREQUENCY:
>>-		val = read_sample_us(pmu, gt_id, __I915_SAMPLE_FREQ_REQ);
>>+		if (gt_id)
>>+			return read_sample_us(pmu, gt_id, __I915_SAMPLE_FREQ_REQ);
>>+
>>+		if (!HAS_EXTRA_GT_LIST(i915))
>>+			return read_sample_us(pmu, 1, __I915_SAMPLE_FREQ_REQ);
>>+
>>+		for_each_gt(gt, i915, i)
>>+			val = max(val, read_sample_us(pmu, i + 1, __I915_SAMPLE_FREQ_REQ));
>>+
>>  		break;
>>  	case I915_PMU_INTERRUPTS:
>>  		val = READ_ONCE(pmu->irq_count);
>>  		break;
>>  	case I915_PMU_RC6_RESIDENCY:
>>-		val = get_rc6(i915->gt[gt_id]);
>>+		if (gt_id)
>>+			return get_rc6(i915->gt[gt_id - 1]);
>>+
>>+		if (!HAS_EXTRA_GT_LIST(i915))
>>+			return get_rc6(i915->gt[0]);
>>+
>>+		val = U64_MAX;
>>+		for_each_gt(gt, i915, i)
>>+			val = min(val, get_rc6(gt));
>>+
>>  		break;
>>  	case I915_PMU_SOFTWARE_GT_AWAKE_TIME:
>>-		val = ktime_to_ns(intel_gt_get_awake_time(to_gt(i915)));
>>+		if (gt_id)
>>+			return ktime_to_ns(intel_gt_get_awake_time(i915->gt[gt_id - 1]));
>>+
>>+		if (!HAS_EXTRA_GT_LIST(i915))
>>+			return ktime_to_ns(intel_gt_get_awake_time(i915->gt[0]));
>>+
>>+		val = 0;
>>+		for_each_gt(gt, i915, i)
>>+			val = max((s64)val, ktime_to_ns(intel_gt_get_awake_time(gt)));
>>  		break;
>>  	}
>>@@ -728,11 +766,14 @@ static void i915_pmu_event_read(struct perf_event *event)
>>  static void i915_pmu_enable(struct perf_event *event)
>>  {
>>+	const unsigned int gt_id = config_gt_id(event->attr.config);
>>  	struct drm_i915_private *i915 =
>>  		container_of(event->pmu, typeof(*i915), pmu.base);
>>  	struct i915_pmu *pmu = &i915->pmu;
>>+	struct intel_gt *gt;
>>  	unsigned long flags;
>>  	unsigned int bit;
>>+	u64 i;
>>  	bit = event_bit(event);
>>  	if (bit == -1)
>>@@ -745,12 +786,42 @@ static void i915_pmu_enable(struct perf_event *event)
>>  	 * the event reference counter.
>>  	 */
>>  	BUILD_BUG_ON(ARRAY_SIZE(pmu->enable_count) != I915_PMU_MASK_BITS);
>>+	BUILD_BUG_ON(BITS_PER_TYPE(pmu->enable) < I915_PMU_MASK_BITS);
>>  	GEM_BUG_ON(bit >= ARRAY_SIZE(pmu->enable_count));
>>  	GEM_BUG_ON(pmu->enable_count[bit] == ~0);
>>  	pmu->enable |= BIT_ULL(bit);
>>  	pmu->enable_count[bit]++;
>>+	/*
>>+	 * The arrays that i915_pmu maintains are now indexed as
>>+	 *
>>+	 * 0 - aggregate events (a.k.a !gt_id)
>>+	 * 1 - gt0
>>+	 * 2 - gt1
>>+	 *
>>+	 * The same logic applies to event_bit masks. The first set of mask are
>>+	 * for aggregate, followed by gt0 and gt1 masks. The idea here is to
>>+	 * enable the event on all gts if the aggregate event bit is set. This
>>+	 * applies only to the non-engine-events.
>>+	 */
>>+	if (!gt_id && !is_engine_event(event)) {
>>+		for_each_gt(gt, i915, i) {
>>+			u64 counter = config_counter(event->attr.config);
>>+			u64 config = ((i + 1) << __I915_PMU_GT_SHIFT) | counter;
>>+			unsigned int bit = config_bit(config);
>>+
>>+			if (bit == -1)
>>+				continue;
>>+
>>+			GEM_BUG_ON(bit >= ARRAY_SIZE(pmu->enable_count));
>>+			GEM_BUG_ON(pmu->enable_count[bit] == ~0);
>>+
>>+			pmu->enable |= BIT_ULL(bit);
>>+			pmu->enable_count[bit]++;
>>+		}
>>+	}
>>+
>>  	/*
>>  	 * Start the sampling timer if needed and not already enabled.
>>  	 */
>>@@ -793,6 +864,7 @@ static void i915_pmu_enable(struct perf_event *event)
>>  static void i915_pmu_disable(struct perf_event *event)
>>  {
>>+	const unsigned int gt_id = config_gt_id(event->attr.config);
>>  	struct drm_i915_private *i915 =
>>  		container_of(event->pmu, typeof(*i915), pmu.base);
>>  	unsigned int bit = event_bit(event);
>>@@ -822,6 +894,26 @@ static void i915_pmu_disable(struct perf_event *event)
>>  		 */
>>  		if (--engine->pmu.enable_count[sample] == 0)
>>  			engine->pmu.enable &= ~BIT(sample);
>>+	} else if (!gt_id) {
>>+		struct intel_gt *gt;
>>+		u64 i;
>>+
>>+		for_each_gt(gt, i915, i) {
>>+			u64 counter = config_counter(event->attr.config);
>>+			u64 config = ((i + 1) << __I915_PMU_GT_SHIFT) | counter;
>>+			unsigned int bit = config_bit(config);
>>+
>>+			if (bit == -1)
>>+				continue;
>>+
>>+			GEM_BUG_ON(bit >= ARRAY_SIZE(pmu->enable_count));
>>+			GEM_BUG_ON(pmu->enable_count[bit] == 0);
>>+
>>+			if (--pmu->enable_count[bit] == 0) {
>>+				pmu->enable &= ~BIT_ULL(bit);
>>+				pmu->timer_enabled &= pmu_needs_timer(pmu, true);
>>+			}
>>+		}
>>  	}
>>  	GEM_BUG_ON(bit >= ARRAY_SIZE(pmu->enable_count));
>>@@ -1002,7 +1094,11 @@ create_event_attributes(struct i915_pmu *pmu)
>>  		const char *name;
>>  		const char *unit;
>>  	} global_events[] = {
>>+		__event(0, "actual-frequency", "M"),
>>+		__event(1, "requested-frequency", "M"),
>>  		__event(2, "interrupts", NULL),
>>+		__event(3, "rc6-residency", "ns"),
>>+		__event(4, "software-gt-awake-time", "ns"),
>>  	};
>>  	static const struct {
>>  		enum drm_i915_pmu_engine_sample sample;
>>@@ -1024,7 +1120,7 @@ create_event_attributes(struct i915_pmu *pmu)
>>  	/* per gt counters */
>>  	for_each_gt(gt, i915, j) {
>>  		for (i = 0; i < ARRAY_SIZE(events); i++) {
>>-			u64 config = ___I915_PMU_OTHER(j, events[i].counter);
>>+			u64 config = ___I915_PMU_OTHER(j + 1, events[i].counter);
>>  			if (!config_status(i915, config))
>>  				count++;
>>@@ -1070,7 +1166,7 @@ create_event_attributes(struct i915_pmu *pmu)
>>  	/* per gt counters */
>>  	for_each_gt(gt, i915, j) {
>>  		for (i = 0; i < ARRAY_SIZE(events); i++) {
>>-			u64 config = ___I915_PMU_OTHER(j, events[i].counter);
>>+			u64 config = ___I915_PMU_OTHER(j + 1, events[i].counter);
>>  			char *str;
>>  			if (config_status(i915, config))
>>diff --git a/drivers/gpu/drm/i915/i915_pmu.h b/drivers/gpu/drm/i915/i915_pmu.h
>>index a708e44a227e..a4cc1eb218fc 100644
>>--- a/drivers/gpu/drm/i915/i915_pmu.h
>>+++ b/drivers/gpu/drm/i915/i915_pmu.h
>>@@ -38,7 +38,7 @@ enum {
>>  	__I915_NUM_PMU_SAMPLERS
>>  };
>>-#define I915_PMU_MAX_GTS (4) /* FIXME */
>>+#define I915_PMU_MAX_GTS (4 + 1) /* FIXME */
>>  /**
>>   * How many different events we track in the global PMU mask.
>>diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h
>>index bbab7f3dbeb4..18794c30027f 100644
>>--- a/include/uapi/drm/i915_drm.h
>>+++ b/include/uapi/drm/i915_drm.h
>>@@ -290,6 +290,7 @@ enum drm_i915_pmu_engine_sample {
>>  	(((__u64)__I915_PMU_ENGINE(0xff, 0xff, 0xf) + 1 + (x)) | \
>>  	((__u64)(gt) << __I915_PMU_GT_SHIFT))
>>+/* Aggregate from all gts */
>>  #define __I915_PMU_OTHER(x) ___I915_PMU_OTHER(0, x)
>>  #define I915_PMU_ACTUAL_FREQUENCY	__I915_PMU_OTHER(0)
>>@@ -300,11 +301,14 @@ enum drm_i915_pmu_engine_sample {
>>  #define I915_PMU_LAST /* Deprecated - do not use */ I915_PMU_RC6_RESIDENCY
>>-#define __I915_PMU_ACTUAL_FREQUENCY(gt)		___I915_PMU_OTHER(gt, 0)
>>-#define __I915_PMU_REQUESTED_FREQUENCY(gt)	___I915_PMU_OTHER(gt, 1)
>>-#define __I915_PMU_INTERRUPTS(gt)		___I915_PMU_OTHER(gt, 2)
>>-#define __I915_PMU_RC6_RESIDENCY(gt)		___I915_PMU_OTHER(gt, 3)
>>-#define __I915_PMU_SOFTWARE_GT_AWAKE_TIME(gt)	___I915_PMU_OTHER(gt, 4)
>>+/* GT specific counters */
>>+#define ____I915_PMU_OTHER(gt, x) ___I915_PMU_OTHER(((gt) + 1), x)
>>+
>>+#define __I915_PMU_ACTUAL_FREQUENCY(gt)		____I915_PMU_OTHER(gt, 0)
>>+#define __I915_PMU_REQUESTED_FREQUENCY(gt)	____I915_PMU_OTHER(gt, 1)
>>+#define __I915_PMU_INTERRUPTS(gt)		____I915_PMU_OTHER(gt, 2)
>>+#define __I915_PMU_RC6_RESIDENCY(gt)		____I915_PMU_OTHER(gt, 3)
>>+#define __I915_PMU_SOFTWARE_GT_AWAKE_TIME(gt)	____I915_PMU_OTHER(gt, 4)
>>  /* Each region is a minimum of 16k, and there are at most 255 of them.
>>   */


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