Re: [PATCH 43/47] drm/i915/guc: Hook GuC scheduling policies up

[John Harrison <john.c.harrison@xxxxxxxxx>]

On 6/24/2021 17:59, Matthew Brost wrote:
> On Thu, Jun 24, 2021 at 12:05:12AM -0700, Matthew Brost wrote:
> > From: John Harrison <John.C.Harrison@xxxxxxxxx>
> >
> > Use the official driver default scheduling policies for configuring
> > the GuC scheduler rather than a bunch of hardcoded values.
> >
> > Signed-off-by: John Harrison <john.c.harrison@xxxxxxxxx>
> > Signed-off-by: Matthew Brost <matthew.brost@xxxxxxxxx>
> > Cc: Jose Souza <jose.souza@xxxxxxxxx>
> > ---
> >   drivers/gpu/drm/i915/gt/intel_engine_types.h  |  1 +
> >   drivers/gpu/drm/i915/gt/uc/intel_guc.h        |  2 +
> >   drivers/gpu/drm/i915/gt/uc/intel_guc_ads.c    | 44 ++++++++++++++++++-
> >   .../gpu/drm/i915/gt/uc/intel_guc_submission.c | 11 +++--
> >   4 files changed, 53 insertions(+), 5 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/i915/gt/intel_engine_types.h b/drivers/gpu/drm/i915/gt/intel_engine_types.h
> > index 0ceffa2be7a7..37db857bb56c 100644
> > --- a/drivers/gpu/drm/i915/gt/intel_engine_types.h
> > +++ b/drivers/gpu/drm/i915/gt/intel_engine_types.h
> > @@ -455,6 +455,7 @@ struct intel_engine_cs {
> >   #define I915_ENGINE_IS_VIRTUAL       BIT(5)
> >   #define I915_ENGINE_HAS_RELATIVE_MMIO BIT(6)
> >   #define I915_ENGINE_REQUIRES_CMD_PARSER BIT(7)
> > +#define I915_ENGINE_WANT_FORCED_PREEMPTION BIT(8)
> >   	unsigned int flags;
> >   
> >   	/*
> > diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc.h b/drivers/gpu/drm/i915/gt/uc/intel_guc.h
> > index c38365cd5fab..905ecbc7dbe3 100644
> > --- a/drivers/gpu/drm/i915/gt/uc/intel_guc.h
> > +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc.h
> > @@ -270,6 +270,8 @@ int intel_guc_engine_failure_process_msg(struct intel_guc *guc,
> >   
> >   void intel_guc_find_hung_context(struct intel_engine_cs *engine);
> >   
> > +int intel_guc_global_policies_update(struct intel_guc *guc);
> > +
> >   void intel_guc_submission_reset_prepare(struct intel_guc *guc);
> >   void intel_guc_submission_reset(struct intel_guc *guc, bool stalled);
> >   void intel_guc_submission_reset_finish(struct intel_guc *guc);
> > diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_ads.c b/drivers/gpu/drm/i915/gt/uc/intel_guc_ads.c
> > index d3e86ab7508f..2ad5fcd4e1b7 100644
> > --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_ads.c
> > +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_ads.c
> > @@ -77,14 +77,54 @@ static u32 guc_ads_blob_size(struct intel_guc *guc)
> >   	       guc_ads_private_data_size(guc);
> >   }
> >   
> > -static void guc_policies_init(struct guc_policies *policies)
> > +static void guc_policies_init(struct intel_guc *guc, struct guc_policies *policies)
> >   {
> > +	struct intel_gt *gt = guc_to_gt(guc);
> > +	struct drm_i915_private *i915 = gt->i915;
> > +
> >   	policies->dpc_promote_time = GLOBAL_POLICY_DEFAULT_DPC_PROMOTE_TIME_US;
> >   	policies->max_num_work_items = GLOBAL_POLICY_MAX_NUM_WI;
> > +
> >   	policies->global_flags = 0;
> > +	if (i915->params.reset < 2)
> > +		policies->global_flags |= GLOBAL_POLICY_DISABLE_ENGINE_RESET;
> > +
> >   	policies->is_valid = 1;
> >   }
> >   
> > +static int guc_action_policies_update(struct intel_guc *guc, u32 policy_offset)
> > +{
> > +	u32 action[] = {
> > +		INTEL_GUC_ACTION_GLOBAL_SCHED_POLICY_CHANGE,
> > +		policy_offset
> > +	};
> > +
> > +	return intel_guc_send(guc, action, ARRAY_SIZE(action));
> > +}
> > +
> > +int intel_guc_global_policies_update(struct intel_guc *guc)
> > +{
> > +	struct __guc_ads_blob *blob = guc->ads_blob;
> > +	struct intel_gt *gt = guc_to_gt(guc);
> > +	intel_wakeref_t wakeref;
> > +	int ret;
> > +
> > +	if (!blob)
> > +		return -ENOTSUPP;
> > +
> > +	GEM_BUG_ON(!blob->ads.scheduler_policies);
> > +
> > +	guc_policies_init(guc, &blob->policies);
> > +
> > +	if (!intel_guc_is_ready(guc))
> > +		return 0;
> > +
> > +	with_intel_runtime_pm(&gt->i915->runtime_pm, wakeref)
> > +		ret = guc_action_policies_update(guc, blob->ads.scheduler_policies);
> > +
> > +	return ret;
> > +}
> > +
> >   static void guc_mapping_table_init(struct intel_gt *gt,
> >   				   struct guc_gt_system_info *system_info)
> >   {
> > @@ -281,7 +321,7 @@ static void __guc_ads_init(struct intel_guc *guc)
> >   	u8 engine_class, guc_class;
> >   
> >   	/* GuC scheduling policies */
> > -	guc_policies_init(&blob->policies);
> > +	guc_policies_init(guc, &blob->policies);
> >   
> >   	/*
> >   	 * GuC expects a per-engine-class context image and size
> > diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
> > index 6188189314d5..a427336ce916 100644
> > --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
> > +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
> > @@ -873,6 +873,7 @@ void intel_guc_submission_reset_finish(struct intel_guc *guc)
> >   	GEM_WARN_ON(atomic_read(&guc->outstanding_submission_g2h));
> >   	atomic_set(&guc->outstanding_submission_g2h, 0);
> >   
> > +	intel_guc_global_policies_update(guc);
> >   	enable_submission(guc);
> >   	intel_gt_unpark_heartbeats(guc_to_gt(guc));
> >   }
> > @@ -1161,8 +1162,12 @@ static void guc_context_policy_init(struct intel_engine_cs *engine,
> >   {
> >   	desc->policy_flags = 0;
> >   
> > -	desc->execution_quantum = CONTEXT_POLICY_DEFAULT_EXECUTION_QUANTUM_US;
> > -	desc->preemption_timeout = CONTEXT_POLICY_DEFAULT_PREEMPTION_TIME_US;
> > +	if (engine->flags & I915_ENGINE_WANT_FORCED_PREEMPTION)
> I can't see where we set this in this series, although I do see a
> selftest we need to fixup that sets this. Perhaps we drop this until we
> fix that selftest? Or at minimum add a comment saying it will be used in
> the future by selftests. What do you think John?
Yeah, it is only ever intended to be used by selftests. So yes, it could 
be punted down the road until the selftest patch. Likewise the 
definition for the flag, too.

John.

> > +		desc->policy_flags |= CONTEXT_POLICY_FLAG_PREEMPT_TO_IDLE;
> > +
> > +	/* NB: For both of these, zero means disabled. */
> > +	desc->execution_quantum = engine->props.timeslice_duration_ms * 1000;
> > +	desc->preemption_timeout = engine->props.preempt_timeout_ms * 1000;
> >   }
> >   
> >   static int guc_lrc_desc_pin(struct intel_context *ce, bool loop)
> > @@ -1945,13 +1950,13 @@ static void guc_default_vfuncs(struct intel_engine_cs *engine)
> >   	engine->set_default_submission = guc_set_default_submission;
> >   
> >   	engine->flags |= I915_ENGINE_HAS_PREEMPTION;
> > +	engine->flags |= I915_ENGINE_HAS_TIMESLICES;
> >   
> >   	/*
> >   	 * TODO: GuC supports timeslicing and semaphores as well, but they're
> Nit, we now support timeslicing. I can fix that up in next rev.
>
> Matt
>
> >   	 * handled by the firmware so some minor tweaks are required before
> >   	 * enabling.
> >   	 *
> > -	 * engine->flags |= I915_ENGINE_HAS_TIMESLICES;
> >   	 * engine->flags |= I915_ENGINE_HAS_SEMAPHORES;
> >   	 */
> >   
> > --
> > 2.28.0
> >
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