[PATCH v3] drm/i915/guc: Use context hints for GT frequency

Rodrigo Vivi rodrigo.vivi at intel.com
Tue Mar 5 22:47:34 UTC 2024


On Mon, Mar 04, 2024 at 03:34:50PM -0800, Vinay Belgaumkar wrote:
> Allow user to provide a low latency context hint. When set, KMD
> sends a hint to GuC which results in special handling for this
> context. SLPC will ramp the GT frequency aggressively every time
> it switches to this context. The down freq threshold will also be
> lower so GuC will ramp down the GT freq for this context more slowly.
> We also disable waitboost for this context as that will interfere with
> the strategy.
> 
> We need to enable the use of SLPC Compute strategy during init, but
> it will apply only to contexts that set this bit during context
> creation.
> 
> Userland can check whether this feature is supported using a new param-
> I915_PARAM_HAS_CONTEXT_FREQ_HINTS. This flag is true for all guc submission
> enabled platforms as they use SLPC for frequency management.
> 
> The Mesa usage model for this flag is here -
> https://gitlab.freedesktop.org/sushmave/mesa/-/commits/compute_hint
> 
> v2: Rename flags as per review suggestions (Rodrigo, Tvrtko).
> Also, use flag bits in intel_context as it allows finer control for
> toggling per engine if needed (Tvrtko).
> 
> v3: Minor review comments (Tvrtko)
> 
> Cc: Rodrigo Vivi <rodrigo.vivi at intel.com>
> Cc: Tvrtko Ursulin <tvrtko.ursulin at linux.intel.com>
> Cc: Sushma Venkatesh Reddy <sushma.venkatesh.reddy at intel.com>
> Acked-by: Rodrigo Vivi <rodrigo.vivi at intel.com>

Reviewed-by: Rodrigo Vivi <rodrigo.vivi at intel.com>

> Signed-off-by: Vinay Belgaumkar <vinay.belgaumkar at intel.com>
> ---
>  drivers/gpu/drm/i915/gem/i915_gem_context.c   | 16 ++++++++++++--
>  .../gpu/drm/i915/gem/i915_gem_context_types.h |  1 +
>  drivers/gpu/drm/i915/gt/intel_context_types.h |  1 +
>  drivers/gpu/drm/i915/gt/intel_rps.c           |  4 ++++
>  .../drm/i915/gt/uc/abi/guc_actions_slpc_abi.h | 21 +++++++++++++++++++
>  drivers/gpu/drm/i915/gt/uc/intel_guc_slpc.c   | 17 +++++++++++++++
>  drivers/gpu/drm/i915/gt/uc/intel_guc_slpc.h   |  1 +
>  .../gpu/drm/i915/gt/uc/intel_guc_submission.c |  6 ++++++
>  drivers/gpu/drm/i915/i915_getparam.c          |  6 ++++++
>  include/uapi/drm/i915_drm.h                   | 15 +++++++++++++
>  10 files changed, 86 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context.c b/drivers/gpu/drm/i915/gem/i915_gem_context.c
> index dcbfe32fd30c..81f65cab1330 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_context.c
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_context.c
> @@ -879,6 +879,7 @@ static int set_proto_ctx_param(struct drm_i915_file_private *fpriv,
>  			       struct i915_gem_proto_context *pc,
>  			       struct drm_i915_gem_context_param *args)
>  {
> +	struct drm_i915_private *i915 = fpriv->i915;
>  	int ret = 0;
>  
>  	switch (args->param) {
> @@ -904,6 +905,13 @@ static int set_proto_ctx_param(struct drm_i915_file_private *fpriv,
>  			pc->user_flags &= ~BIT(UCONTEXT_BANNABLE);
>  		break;
>  
> +	case I915_CONTEXT_PARAM_LOW_LATENCY:
> +		if (intel_uc_uses_guc_submission(&to_gt(i915)->uc))
> +			pc->user_flags |= BIT(UCONTEXT_LOW_LATENCY);
> +		else
> +			ret = -EINVAL;
> +		break;
> +
>  	case I915_CONTEXT_PARAM_RECOVERABLE:
>  		if (args->size)
>  			ret = -EINVAL;
> @@ -992,6 +1000,9 @@ static int intel_context_set_gem(struct intel_context *ce,
>  	if (sseu.slice_mask && !WARN_ON(ce->engine->class != RENDER_CLASS))
>  		ret = intel_context_reconfigure_sseu(ce, sseu);
>  
> +	if (test_bit(UCONTEXT_LOW_LATENCY, &ctx->user_flags))
> +		__set_bit(CONTEXT_LOW_LATENCY, &ce->flags);
> +
>  	return ret;
>  }
>  
> @@ -1630,6 +1641,9 @@ i915_gem_create_context(struct drm_i915_private *i915,
>  	if (vm)
>  		ctx->vm = vm;
>  
> +	/* Assign early so intel_context_set_gem can access these flags */
> +	ctx->user_flags = pc->user_flags;
> +
>  	mutex_init(&ctx->engines_mutex);
>  	if (pc->num_user_engines >= 0) {
>  		i915_gem_context_set_user_engines(ctx);
> @@ -1652,8 +1666,6 @@ i915_gem_create_context(struct drm_i915_private *i915,
>  	 * is no remap info, it will be a NOP. */
>  	ctx->remap_slice = ALL_L3_SLICES(i915);
>  
> -	ctx->user_flags = pc->user_flags;
> -
>  	for (i = 0; i < ARRAY_SIZE(ctx->hang_timestamp); i++)
>  		ctx->hang_timestamp[i] = jiffies - CONTEXT_FAST_HANG_JIFFIES;
>  
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context_types.h b/drivers/gpu/drm/i915/gem/i915_gem_context_types.h
> index 03bc7f9d191b..b6d97da63d1f 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_context_types.h
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_context_types.h
> @@ -338,6 +338,7 @@ struct i915_gem_context {
>  #define UCONTEXT_BANNABLE		2
>  #define UCONTEXT_RECOVERABLE		3
>  #define UCONTEXT_PERSISTENCE		4
> +#define UCONTEXT_LOW_LATENCY		5
>  
>  	/**
>  	 * @flags: small set of booleans
> diff --git a/drivers/gpu/drm/i915/gt/intel_context_types.h b/drivers/gpu/drm/i915/gt/intel_context_types.h
> index 7eccbd70d89f..ed95a7b57cbb 100644
> --- a/drivers/gpu/drm/i915/gt/intel_context_types.h
> +++ b/drivers/gpu/drm/i915/gt/intel_context_types.h
> @@ -130,6 +130,7 @@ struct intel_context {
>  #define CONTEXT_PERMA_PIN		11
>  #define CONTEXT_IS_PARKING		12
>  #define CONTEXT_EXITING			13
> +#define CONTEXT_LOW_LATENCY		14
>  
>  	struct {
>  		u64 timeout_us;
> diff --git a/drivers/gpu/drm/i915/gt/intel_rps.c b/drivers/gpu/drm/i915/gt/intel_rps.c
> index 9c6812257ac2..a929aa6e3c85 100644
> --- a/drivers/gpu/drm/i915/gt/intel_rps.c
> +++ b/drivers/gpu/drm/i915/gt/intel_rps.c
> @@ -1013,6 +1013,10 @@ void intel_rps_boost(struct i915_request *rq)
>  	if (i915_request_signaled(rq) || i915_request_has_waitboost(rq))
>  		return;
>  
> +	/* Waitboost is not needed for contexts marked with a Freq hint */
> +	if (test_bit(CONTEXT_LOW_LATENCY, &rq->context->flags))
> +		return;
> +
>  	/* Serializes with i915_request_retire() */
>  	if (!test_and_set_bit(I915_FENCE_FLAG_BOOST, &rq->fence.flags)) {
>  		struct intel_rps *rps = &READ_ONCE(rq->engine)->gt->rps;
> diff --git a/drivers/gpu/drm/i915/gt/uc/abi/guc_actions_slpc_abi.h b/drivers/gpu/drm/i915/gt/uc/abi/guc_actions_slpc_abi.h
> index 811add10c30d..c34674e797c6 100644
> --- a/drivers/gpu/drm/i915/gt/uc/abi/guc_actions_slpc_abi.h
> +++ b/drivers/gpu/drm/i915/gt/uc/abi/guc_actions_slpc_abi.h
> @@ -207,6 +207,27 @@ struct slpc_shared_data {
>  	u8 reserved_mode_definition[4096];
>  } __packed;
>  
> +struct slpc_context_frequency_request {
> +	u32 frequency_request:16;
> +	u32 reserved:12;
> +	u32 is_compute:1;
> +	u32 ignore_busyness:1;
> +	u32 is_minimum:1;
> +	u32 is_predefined:1;
> +} __packed;
> +
> +#define SLPC_CTX_FREQ_REQ_IS_COMPUTE		REG_BIT(28)
> +
> +struct slpc_optimized_strategies {
> +	u32 compute:1;
> +	u32 async_flip:1;
> +	u32 media:1;
> +	u32 vsync_flip:1;
> +	u32 reserved:28;
> +} __packed;
> +
> +#define SLPC_OPTIMIZED_STRATEGY_COMPUTE		REG_BIT(0)
> +
>  /**
>   * DOC: SLPC H2G MESSAGE FORMAT
>   *
> diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_slpc.c b/drivers/gpu/drm/i915/gt/uc/intel_guc_slpc.c
> index 3e681ab6fbf9..706fffca698b 100644
> --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_slpc.c
> +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_slpc.c
> @@ -537,6 +537,20 @@ int intel_guc_slpc_get_min_freq(struct intel_guc_slpc *slpc, u32 *val)
>  	return ret;
>  }
>  
> +int intel_guc_slpc_set_strategy(struct intel_guc_slpc *slpc, u32 val)
> +{
> +	struct drm_i915_private *i915 = slpc_to_i915(slpc);
> +	intel_wakeref_t wakeref;
> +	int ret = 0;
> +
> +	with_intel_runtime_pm(&i915->runtime_pm, wakeref)
> +		ret = slpc_set_param(slpc,
> +				     SLPC_PARAM_STRATEGIES,
> +				     val);
> +
> +	return ret;
> +}
> +
>  int intel_guc_slpc_set_media_ratio_mode(struct intel_guc_slpc *slpc, u32 val)
>  {
>  	struct drm_i915_private *i915 = slpc_to_i915(slpc);
> @@ -711,6 +725,9 @@ int intel_guc_slpc_enable(struct intel_guc_slpc *slpc)
>  	/* Set cached media freq ratio mode */
>  	intel_guc_slpc_set_media_ratio_mode(slpc, slpc->media_ratio_mode);
>  
> +	/* Enable SLPC Optimized Strategy for compute */
> +	intel_guc_slpc_set_strategy(slpc, SLPC_OPTIMIZED_STRATEGY_COMPUTE);
> +
>  	return 0;
>  }
>  
> diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_slpc.h b/drivers/gpu/drm/i915/gt/uc/intel_guc_slpc.h
> index 6ac6503c39d4..1cb5fd44f05c 100644
> --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_slpc.h
> +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_slpc.h
> @@ -45,5 +45,6 @@ void intel_guc_pm_intrmsk_enable(struct intel_gt *gt);
>  void intel_guc_slpc_boost(struct intel_guc_slpc *slpc);
>  void intel_guc_slpc_dec_waiters(struct intel_guc_slpc *slpc);
>  int intel_guc_slpc_set_ignore_eff_freq(struct intel_guc_slpc *slpc, bool val);
> +int intel_guc_slpc_set_strategy(struct intel_guc_slpc *slpc, u32 val);
>  
>  #endif
> 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 cc076e9302ad..e5c645137cfe 100644
> --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
> +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
> @@ -2645,6 +2645,7 @@ MAKE_CONTEXT_POLICY_ADD(execution_quantum, EXECUTION_QUANTUM)
>  MAKE_CONTEXT_POLICY_ADD(preemption_timeout, PREEMPTION_TIMEOUT)
>  MAKE_CONTEXT_POLICY_ADD(priority, SCHEDULING_PRIORITY)
>  MAKE_CONTEXT_POLICY_ADD(preempt_to_idle, PREEMPT_TO_IDLE_ON_QUANTUM_EXPIRY)
> +MAKE_CONTEXT_POLICY_ADD(slpc_ctx_freq_req, SLPM_GT_FREQUENCY)
>  
>  #undef MAKE_CONTEXT_POLICY_ADD
>  
> @@ -2664,6 +2665,7 @@ static int guc_context_policy_init_v70(struct intel_context *ce, bool loop)
>  	struct context_policy policy;
>  	u32 execution_quantum;
>  	u32 preemption_timeout;
> +	u32 slpc_ctx_freq_req = 0;
>  	unsigned long flags;
>  	int ret;
>  
> @@ -2675,11 +2677,15 @@ static int guc_context_policy_init_v70(struct intel_context *ce, bool loop)
>  	execution_quantum = engine->props.timeslice_duration_ms * 1000;
>  	preemption_timeout = engine->props.preempt_timeout_ms * 1000;
>  
> +	if (ce && (ce->flags & BIT(CONTEXT_LOW_LATENCY)))
> +		slpc_ctx_freq_req |= SLPC_CTX_FREQ_REQ_IS_COMPUTE;
> +
>  	__guc_context_policy_start_klv(&policy, ce->guc_id.id);
>  
>  	__guc_context_policy_add_priority(&policy, ce->guc_state.prio);
>  	__guc_context_policy_add_execution_quantum(&policy, execution_quantum);
>  	__guc_context_policy_add_preemption_timeout(&policy, preemption_timeout);
> +	__guc_context_policy_add_slpc_ctx_freq_req(&policy, slpc_ctx_freq_req);
>  
>  	if (engine->flags & I915_ENGINE_WANT_FORCED_PREEMPTION)
>  		__guc_context_policy_add_preempt_to_idle(&policy, 1);
> diff --git a/drivers/gpu/drm/i915/i915_getparam.c b/drivers/gpu/drm/i915/i915_getparam.c
> index 5c3fec63cb4c..95c58805b2a4 100644
> --- a/drivers/gpu/drm/i915/i915_getparam.c
> +++ b/drivers/gpu/drm/i915/i915_getparam.c
> @@ -155,6 +155,12 @@ int i915_getparam_ioctl(struct drm_device *dev, void *data,
>  		 */
>  		value = 1;
>  		break;
> +	case I915_PARAM_HAS_CONTEXT_FREQ_HINT:
> +		if (intel_uc_uses_guc_submission(&to_gt(i915)->uc))
> +			value = 1;
> +		else
> +			value = -EINVAL;
> +		break;
>  	case I915_PARAM_HAS_CONTEXT_ISOLATION:
>  		value = intel_engines_has_context_isolation(i915);
>  		break;
> diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h
> index 1279a6b2bece..a8b3dd594831 100644
> --- a/include/uapi/drm/i915_drm.h
> +++ b/include/uapi/drm/i915_drm.h
> @@ -806,6 +806,12 @@ typedef struct drm_i915_irq_wait {
>   */
>  #define I915_PARAM_PXP_STATUS		 58
>  
> +/*
> + * Query if kernel allows marking a context to send a Freq hint to SLPC. This
> + * will enable use of the strategies allowed by the SLPC algorithm.
> + */
> +#define I915_PARAM_HAS_CONTEXT_FREQ_HINT	59
> +
>  /* Must be kept compact -- no holes and well documented */
>  
>  /**
> @@ -2148,6 +2154,15 @@ struct drm_i915_gem_context_param {
>   * -EIO: The firmware did not succeed in creating the protected context.
>   */
>  #define I915_CONTEXT_PARAM_PROTECTED_CONTENT    0xd
> +
> +/*
> + * I915_CONTEXT_PARAM_IS_COMPUTE:
> + *
> + * Mark this context as a Compute related workload which requires aggressive GT
> + * frequency scaling. Query I915_PARAM_HAS_CONTEXT_COMPUTE to check if the kernel
> + * supports this functionality.
> + */
> +#define I915_CONTEXT_PARAM_LOW_LATENCY		0xe
>  /* Must be kept compact -- no holes and well documented */
>  
>  	/** @value: Context parameter value to be set or queried */
> -- 
> 2.38.1
> 


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