[PATCH v4 7/8] drm/i915: count powergating transitions per engine

[Lionel Landwerlin <lionel.g.landwerlin@intel.com>]

This can be used to monitor the number of powergating transition
changes for a particular workload.

Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
---
 drivers/gpu/drm/i915/intel_engine_cs.c  | 3 +++
 drivers/gpu/drm/i915/intel_lrc.c        | 1 +
 drivers/gpu/drm/i915/intel_ringbuffer.h | 6 ++++++
 3 files changed, 10 insertions(+)

diff --git a/drivers/gpu/drm/i915/intel_engine_cs.c b/drivers/gpu/drm/i915/intel_engine_cs.c
index 1bab0447c9dc..c795a674abf0 100644
--- a/drivers/gpu/drm/i915/intel_engine_cs.c
+++ b/drivers/gpu/drm/i915/intel_engine_cs.c
@@ -505,6 +505,7 @@ void intel_engine_setup_common(struct intel_engine_cs *engine)
 	i915_timeline_init(engine->i915, &engine->timeline, engine->name);
 
 	memset(&engine->last_sseu, 0, sizeof(engine->last_sseu));
+	atomic_set(&engine->sseu_transitions, 0);
 
 	intel_engine_init_execlist(engine);
 	intel_engine_init_hangcheck(engine);
@@ -1439,6 +1440,8 @@ void intel_engine_dump(struct intel_engine_cs *engine,
 	hexdump(m, engine->status_page.page_addr, PAGE_SIZE);
 
 	drm_printf(m, "Idle? %s\n", yesno(intel_engine_is_idle(engine)));
+
+	drm_printf(m, "Powergating transitions: %u\n", atomic_read(&engine->sseu_transitions));
 }
 
 static u8 user_class_map[] = {
diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
index c9a51185b7fe..d0c429c4bd35 100644
--- a/drivers/gpu/drm/i915/intel_lrc.c
+++ b/drivers/gpu/drm/i915/intel_lrc.c
@@ -542,6 +542,7 @@ static void maybe_enable_noa_reprogram(struct i915_request *rq)
 	*cs++ = upper_32_bits(engine->noa_reprogram_vma->node.start);
 
 	engine->last_sseu = rq->sseu;
+	atomic_inc(&engine->sseu_transitions);
 }
 
 static void port_assign(struct execlist_port *port, struct i915_request *rq)
diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.h b/drivers/gpu/drm/i915/intel_ringbuffer.h
index 955518a5396f..80819172619e 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.h
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.h
@@ -357,6 +357,12 @@ struct intel_engine_cs {
 	 */
 	union intel_sseu last_sseu;
 
+	/**
+	 * @sseu_transitions: A counter of the number of powergating
+	 * transition this engine has gone through.
+	 */
+	atomic_t sseu_transitions;
+
 	atomic_t irq_count;
 	unsigned long irq_posted;
 #define ENGINE_IRQ_BREADCRUMB 0
-- 
2.17.0

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