Re: [PATCH] drm/i915/slpc: Add sysfs for SLPC power profiles

[Rodrigo Vivi <rodrigo.vivi@intel.com>]

On Mon, Dec 16, 2024 at 04:57:04PM -0800, Vinay Belgaumkar wrote:
> Default SLPC power profile is Base(0). Power Saving mode(1)
> has conservative up/down thresholds and is suitable for use with
> apps that typically need to be power efficient.
> 
> Cc: Sushma Venkatesh Reddy <sushma.venkatesh.reddy@intel.com>
> Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
> Signed-off-by: Vinay Belgaumkar <vinay.belgaumkar@intel.com>
> ---
>  drivers/gpu/drm/i915/gt/intel_gt_sysfs_pm.c   | 35 +++++++++++++++++++
>  .../drm/i915/gt/uc/abi/guc_actions_slpc_abi.h |  5 +++
>  drivers/gpu/drm/i915/gt/uc/intel_guc_slpc.c   | 33 +++++++++++++++++
>  drivers/gpu/drm/i915/gt/uc/intel_guc_slpc.h   |  1 +
>  .../gpu/drm/i915/gt/uc/intel_guc_slpc_types.h |  2 ++
>  5 files changed, 76 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/gt/intel_gt_sysfs_pm.c b/drivers/gpu/drm/i915/gt/intel_gt_sysfs_pm.c
> index d7784650e4d9..52a5ff94a0e3 100644
> --- a/drivers/gpu/drm/i915/gt/intel_gt_sysfs_pm.c
> +++ b/drivers/gpu/drm/i915/gt/intel_gt_sysfs_pm.c
> @@ -464,6 +464,33 @@ static ssize_t slpc_ignore_eff_freq_store(struct kobject *kobj,
>  	return err ?: count;
>  }
>  
> +static ssize_t slpc_power_profile_show(struct kobject *kobj,
> +				       struct kobj_attribute *attr,
> +				       char *buff)
> +{
> +	struct intel_gt *gt = intel_gt_sysfs_get_drvdata(kobj, attr->attr.name);
> +	struct intel_guc_slpc *slpc = &gt->uc.guc.slpc;
> +
> +	return sysfs_emit(buff, "%u\n", slpc->power_profile);

what if we do something like this:

cat /sys/class/drm/card1/gt/gt0/slpc_power_profile
[balanced] power_savings

echo power_savings > /sys/class/drm/card1/gt/gt0/slpc_power_profile

cat /sys/class/drm/card1/gt/gt0/slpc_power_profile
balanced [power_savings]

And second question, shouldn't we disable waitboost so this won't
compete?

Also I believe we should provide some kernel documentation documenting
what would be the governor levels like and recommended settings for
each level.

And then in Xe we should probably add a governor selection in the same
style as devfreq, but with our configs...

Thoughts?

But the code looks good and I believe many cases out there could benefit
of some extra Watts saved by having this option available...

> +}
> +
> +static ssize_t slpc_power_profile_store(struct kobject *kobj,
> +					struct kobj_attribute *attr,
> +					const char *buff, size_t count)
> +{
> +	struct intel_gt *gt = intel_gt_sysfs_get_drvdata(kobj, attr->attr.name);
> +	struct intel_guc_slpc *slpc = &gt->uc.guc.slpc;
> +	int err;
> +	u32 val;
> +
> +	err = kstrtou32(buff, 0, &val);
> +	if (err)
> +		return err;
> +
> +	err = intel_guc_slpc_set_power_profile(slpc, val);
> +	return err ?: count;
> +}
> +
>  struct intel_gt_bool_throttle_attr {
>  	struct attribute attr;
>  	ssize_t (*show)(struct kobject *kobj, struct kobj_attribute *attr,
> @@ -668,6 +695,7 @@ INTEL_GT_ATTR_RO(media_RP0_freq_mhz);
>  INTEL_GT_ATTR_RO(media_RPn_freq_mhz);
>  
>  INTEL_GT_ATTR_RW(slpc_ignore_eff_freq);
> +INTEL_GT_ATTR_RW(slpc_power_profile);
>  
>  static const struct attribute *media_perf_power_attrs[] = {
>  	&attr_media_freq_factor.attr,
> @@ -864,6 +892,13 @@ void intel_gt_sysfs_pm_init(struct intel_gt *gt, struct kobject *kobj)
>  			gt_warn(gt, "failed to create ignore_eff_freq sysfs (%pe)", ERR_PTR(ret));
>  	}
>  
> +	if (intel_uc_uses_guc_slpc(&gt->uc)) {
> +		ret = sysfs_create_file(kobj, &attr_slpc_power_profile.attr);
> +		if (ret)
> +			gt_warn(gt, "failed to create slpc_power_profile sysfs (%pe)",
> +				    ERR_PTR(ret));
> +	}
> +
>  	if (i915_mmio_reg_valid(intel_gt_perf_limit_reasons_reg(gt))) {
>  		ret = sysfs_create_files(kobj, throttle_reason_attrs);
>  		if (ret)
> 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 c34674e797c6..6de87ae5669e 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
> @@ -228,6 +228,11 @@ struct slpc_optimized_strategies {
>  
>  #define SLPC_OPTIMIZED_STRATEGY_COMPUTE		REG_BIT(0)
>  
> +enum slpc_power_profiles {
> +	SLPC_POWER_PROFILES_BASE = 0x0,
> +	SLPC_POWER_PROFILES_POWER_SAVING = 0x1
> +};
> +
>  /**
>   * 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 706fffca698b..0ee88ee347ae 100644
> --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_slpc.c
> +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_slpc.c
> @@ -265,6 +265,8 @@ int intel_guc_slpc_init(struct intel_guc_slpc *slpc)
>  	slpc->num_boosts = 0;
>  	slpc->media_ratio_mode = SLPC_MEDIA_RATIO_MODE_DYNAMIC_CONTROL;
>  
> +	slpc->power_profile = SLPC_POWER_PROFILES_BASE;
> +
>  	mutex_init(&slpc->lock);
>  	INIT_WORK(&slpc->boost_work, slpc_boost_work);
>  
> @@ -567,6 +569,34 @@ int intel_guc_slpc_set_media_ratio_mode(struct intel_guc_slpc *slpc, u32 val)
>  	return ret;
>  }
>  
> +int intel_guc_slpc_set_power_profile(struct intel_guc_slpc *slpc, u32 val)
> +{
> +	struct drm_i915_private *i915 = slpc_to_i915(slpc);
> +	intel_wakeref_t wakeref;
> +	int ret = 0;
> +
> +	if (val > SLPC_POWER_PROFILES_POWER_SAVING)
> +		return -EINVAL;
> +
> +	mutex_lock(&slpc->lock);
> +	wakeref = intel_runtime_pm_get(&i915->runtime_pm);
> +
> +	ret = slpc_set_param(slpc,
> +			     SLPC_PARAM_POWER_PROFILE,
> +			     val);
> +	if (ret)
> +		guc_err(slpc_to_guc(slpc),
> +			"Failed to set power profile to %d: %pe\n",
> +			 val, ERR_PTR(ret));
> +	else
> +		slpc->power_profile = val;
> +
> +	intel_runtime_pm_put(&i915->runtime_pm, wakeref);
> +	mutex_unlock(&slpc->lock);
> +
> +	return ret;
> +}
> +
>  void intel_guc_pm_intrmsk_enable(struct intel_gt *gt)
>  {
>  	u32 pm_intrmsk_mbz = 0;
> @@ -728,6 +758,9 @@ int intel_guc_slpc_enable(struct intel_guc_slpc *slpc)
>  	/* Enable SLPC Optimized Strategy for compute */
>  	intel_guc_slpc_set_strategy(slpc, SLPC_OPTIMIZED_STRATEGY_COMPUTE);
>  
> +	/* Set cached value of power_profile */
> +	intel_guc_slpc_set_power_profile(slpc, slpc->power_profile);
> +
>  	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 1cb5fd44f05c..fc9f761b4372 100644
> --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_slpc.h
> +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_slpc.h
> @@ -46,5 +46,6 @@ 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);
> +int intel_guc_slpc_set_power_profile(struct intel_guc_slpc *slpc, u32 val);
>  
>  #endif
> diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_slpc_types.h b/drivers/gpu/drm/i915/gt/uc/intel_guc_slpc_types.h
> index a88651331497..2351a1693aa1 100644
> --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_slpc_types.h
> +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_slpc_types.h
> @@ -33,6 +33,8 @@ struct intel_guc_slpc {
>  	u32 max_freq_softlimit;
>  	bool ignore_eff_freq;
>  
> +	u32 power_profile;
> +
>  	/* cached media ratio mode */
>  	u32 media_ratio_mode;
>  
> -- 
> 2.38.1
>