[Intel-gfx] [RFC 12/14] drm/i915: Interface for controling engine stats collection
Tvrtko Ursulin
tvrtko.ursulin at linux.intel.com
Wed Jul 19 09:34:14 UTC 2017
Hi Ben,
On 18/07/2017 15:36, Tvrtko Ursulin wrote:
> From: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
>
> Enables other i915 components to enable and disable
> the facility as needed.
>
> Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
> ---
> drivers/gpu/drm/i915/intel_engine_cs.c | 53 +++++++++++++++++++++++++++++++++
> drivers/gpu/drm/i915/intel_ringbuffer.h | 5 ++++
> 2 files changed, 58 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/intel_engine_cs.c b/drivers/gpu/drm/i915/intel_engine_cs.c
> index 3e5e08c6b5ef..03e7459bad06 100644
> --- a/drivers/gpu/drm/i915/intel_engine_cs.c
> +++ b/drivers/gpu/drm/i915/intel_engine_cs.c
> @@ -29,6 +29,8 @@
> #include "intel_lrc.h"
>
> DEFINE_STATIC_KEY_FALSE(i915_engine_stats_key);
> +static DEFINE_MUTEX(i915_engine_stats_mutex);
> +static int i915_engine_stats_ref;
>
> /* Haswell does have the CXT_SIZE register however it does not appear to be
> * valid. Now, docs explain in dwords what is in the context object. The full
> @@ -1340,6 +1342,57 @@ void intel_engines_mark_idle(struct drm_i915_private *i915)
> }
> }
>
> +int intel_enable_engine_stats(struct drm_i915_private *dev_priv)
> +{
> + if (!i915.enable_execlists)
> + return -ENODEV;
> +
> + mutex_lock(&i915_engine_stats_mutex);
> + if (i915_engine_stats_ref++ == 0) {
> + struct intel_engine_cs *engine;
> + enum intel_engine_id id;
> +
> + for_each_engine(engine, dev_priv, id) {
> + memset(&engine->stats, 0, sizeof(engine->stats));
> + spin_lock_init(&engine->stats.lock);
> + }
> +
> + static_branch_enable(&i915_engine_stats_key);
> + }
> + mutex_unlock(&i915_engine_stats_mutex);
> +
> + return 0;
> +}
> +
> +void intel_disable_engine_stats(void)
> +{
> + mutex_lock(&i915_engine_stats_mutex);
> + if (--i915_engine_stats_ref == 0)
> + static_branch_disable(&i915_engine_stats_key);
> + mutex_unlock(&i915_engine_stats_mutex);
> +}
> +
> +u64 intel_engine_get_current_busy_ns(struct intel_engine_cs *engine)
> +{
> + unsigned long flags;
> + u64 total;
> +
> + spin_lock_irqsave(&engine->stats.lock, flags);
> +
> + total = engine->stats.total;
> +
> + /*
> + * If the engine is executing something at the moment
> + * add it to the total.
> + */
> + if (engine->stats.ref)
> + total += ktime_get_real_ns() - engine->stats.start;
> +
> + spin_unlock_irqrestore(&engine->stats.lock, flags);
> +
> + return total;
> +}
> +
> #if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)
> #include "selftests/mock_engine.c"
> #endif
> diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.h b/drivers/gpu/drm/i915/intel_ringbuffer.h
> index 2eb1e970ad06..e0f495a6d0d9 100644
> --- a/drivers/gpu/drm/i915/intel_ringbuffer.h
> +++ b/drivers/gpu/drm/i915/intel_ringbuffer.h
> @@ -776,4 +776,9 @@ static inline void intel_engine_context_out(struct intel_engine_cs *engine)
> }
> }
>
> +int intel_enable_engine_stats(struct drm_i915_private *i915);
> +void intel_disable_engine_stats(void);
> +
> +u64 intel_engine_get_current_busy_ns(struct intel_engine_cs *engine);
If we exported these symbols for other modules to use, what kind of API
would they need? Presumably not per-engine but something to give the
aggregated busyness of all engines? Or I have misunderstood you that
there is this requirement?
Regards,
Tvrtko
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