Re: [PATCH v3 2/5] drm/amdgpu: add new functions to set GPU power profile

["Lazar, Lijo" <lijo.lazar@amd.com>]

On 9/27/2022 3:10 AM, Shashank Sharma wrote:
> This patch adds new functions which will allow a user to
> change the GPU power profile based a GPU workload hint
> flag.
> 
> Cc: Alex Deucher <alexander.deucher@amd.com>
> Signed-off-by: Shashank Sharma <shashank.sharma@amd.com>
> ---
>   drivers/gpu/drm/amd/amdgpu/Makefile           |  2 +-
>   .../gpu/drm/amd/amdgpu/amdgpu_ctx_workload.c  | 97 +++++++++++++++++++
>   drivers/gpu/drm/amd/amdgpu/amdgpu_device.c    |  1 +
>   .../gpu/drm/amd/include/amdgpu_ctx_workload.h | 54 +++++++++++
>   drivers/gpu/drm/amd/pm/inc/amdgpu_dpm.h       |  5 +
>   5 files changed, 158 insertions(+), 1 deletion(-)
>   create mode 100644 drivers/gpu/drm/amd/amdgpu/amdgpu_ctx_workload.c
>   create mode 100644 drivers/gpu/drm/amd/include/amdgpu_ctx_workload.h
> 
> diff --git a/drivers/gpu/drm/amd/amdgpu/Makefile b/drivers/gpu/drm/amd/amdgpu/Makefile
> index 5a283d12f8e1..34679c657ecc 100644
> --- a/drivers/gpu/drm/amd/amdgpu/Makefile
> +++ b/drivers/gpu/drm/amd/amdgpu/Makefile
> @@ -50,7 +50,7 @@ amdgpu-y += amdgpu_device.o amdgpu_kms.o \
>   	atombios_dp.o amdgpu_afmt.o amdgpu_trace_points.o \
>   	atombios_encoders.o amdgpu_sa.o atombios_i2c.o \
>   	amdgpu_dma_buf.o amdgpu_vm.o amdgpu_vm_pt.o amdgpu_ib.o amdgpu_pll.o \
> -	amdgpu_ucode.o amdgpu_bo_list.o amdgpu_ctx.o amdgpu_sync.o \
> +	amdgpu_ucode.o amdgpu_bo_list.o amdgpu_ctx.o amdgpu_ctx_workload.o amdgpu_sync.o \
>   	amdgpu_gtt_mgr.o amdgpu_preempt_mgr.o amdgpu_vram_mgr.o amdgpu_virt.o \
>   	amdgpu_atomfirmware.o amdgpu_vf_error.o amdgpu_sched.o \
>   	amdgpu_debugfs.o amdgpu_ids.o amdgpu_gmc.o \
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ctx_workload.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ctx_workload.c
> new file mode 100644
> index 000000000000..a11cf29bc388
> --- /dev/null
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ctx_workload.c
> @@ -0,0 +1,97 @@
> +/*
> + * Copyright 2022 Advanced Micro Devices, Inc.
> + *
> + * Permission is hereby granted, free of charge, to any person obtaining a
> + * copy of this software and associated documentation files (the "Software"),
> + * to deal in the Software without restriction, including without limitation
> + * the rights to use, copy, modify, merge, publish, distribute, sublicense,
> + * and/or sell copies of the Software, and to permit persons to whom the
> + * Software is furnished to do so, subject to the following conditions:
> + *
> + * The above copyright notice and this permission notice shall be included in
> + * all copies or substantial portions of the Software.
> + *
> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
> + * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
> + * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
> + * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
> + * OTHER DEALINGS IN THE SOFTWARE.
> + *
> + */
> +#include <drm/drm.h>
> +#include "kgd_pp_interface.h"
> +#include "amdgpu_ctx_workload.h"
> +
> +static enum PP_SMC_POWER_PROFILE
> +amdgpu_workload_to_power_profile(uint32_t hint)
> +{
> +	switch (hint) {
> +	case AMDGPU_CTX_WORKLOAD_HINT_NONE:
> +	default:
> +		return PP_SMC_POWER_PROFILE_BOOTUP_DEFAULT;
> +
> +	case AMDGPU_CTX_WORKLOAD_HINT_3D:
> +		return PP_SMC_POWER_PROFILE_FULLSCREEN3D;
> +	case AMDGPU_CTX_WORKLOAD_HINT_VIDEO:
> +		return PP_SMC_POWER_PROFILE_VIDEO;
> +	case AMDGPU_CTX_WORKLOAD_HINT_VR:
> +		return PP_SMC_POWER_PROFILE_VR;
> +	case AMDGPU_CTX_WORKLOAD_HINT_COMPUTE:
> +		return PP_SMC_POWER_PROFILE_COMPUTE;
> +	}
> +}
> +
> +int amdgpu_set_workload_profile(struct amdgpu_device *adev,
> +				uint32_t hint)
> +{
> +	int ret = 0;
> +	enum PP_SMC_POWER_PROFILE profile =
> +			amdgpu_workload_to_power_profile(hint);
> +
> +	if (adev->pm.workload_mode == hint)
> +		return 0;
> +
> +	mutex_lock(&adev->pm.smu_workload_lock);

If it's all about pm subsystem variable accesses, this API should rather 
be inside amd/pm subsystem. No need to expose the variable outside pm 
subsytem. Also currently all amdgpu_dpm* calls are protected under one 
mutex. Then this extra lock won't be needed.

> +
> +	if (adev->pm.workload_mode == hint)
> +		goto unlock;
> +
> +	ret = amdgpu_dpm_switch_power_profile(adev, profile, 1);
> +	if (!ret)
> +		adev->pm.workload_mode = hint;
> +	atomic_inc(&adev->pm.workload_switch_ref);

Why is this reference kept? The swtiching happens inside a lock and 
there is already a check not to switch if the hint matches with current 
workload.

Thanks,
Lijo

> +
> +unlock:
> +	mutex_unlock(&adev->pm.smu_workload_lock);
> +	return ret;
> +}
> +
> +int amdgpu_clear_workload_profile(struct amdgpu_device *adev,
> +				  uint32_t hint)
> +{
> +	int ret = 0;
> +	enum PP_SMC_POWER_PROFILE profile =
> +			amdgpu_workload_to_power_profile(hint);
> +
> +	if (hint == AMDGPU_CTX_WORKLOAD_HINT_NONE)
> +		return 0;
> +
> +	/* Do not reset GPU power profile if another reset is coming */
> +	if (atomic_dec_return(&adev->pm.workload_switch_ref) > 0)
> +		return 0;
> +
> +	mutex_lock(&adev->pm.smu_workload_lock);
> +
> +	if (adev->pm.workload_mode != hint)
> +		goto unlock;
> +
> +	ret = amdgpu_dpm_switch_power_profile(adev, profile, 0);
> +	if (!ret)
> +		adev->pm.workload_mode = AMDGPU_CTX_WORKLOAD_HINT_NONE;
> +
> +unlock:
> +	mutex_unlock(&adev->pm.smu_workload_lock);
> +	return ret;
> +}
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> index be7aff2d4a57..1f0f64662c04 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> @@ -3554,6 +3554,7 @@ int amdgpu_device_init(struct amdgpu_device *adev,
>   	mutex_init(&adev->psp.mutex);
>   	mutex_init(&adev->notifier_lock);
>   	mutex_init(&adev->pm.stable_pstate_ctx_lock);
> +	mutex_init(&adev->pm.smu_workload_lock);
>   	mutex_init(&adev->benchmark_mutex);
>   
>   	amdgpu_device_init_apu_flags(adev);
> diff --git a/drivers/gpu/drm/amd/include/amdgpu_ctx_workload.h b/drivers/gpu/drm/amd/include/amdgpu_ctx_workload.h
> new file mode 100644
> index 000000000000..6060fc53c3b0
> --- /dev/null
> +++ b/drivers/gpu/drm/amd/include/amdgpu_ctx_workload.h
> @@ -0,0 +1,54 @@
> +/*
> + * Copyright 2022 Advanced Micro Devices, Inc.
> + *
> + * Permission is hereby granted, free of charge, to any person obtaining a
> + * copy of this software and associated documentation files (the "Software"),
> + * to deal in the Software without restriction, including without limitation
> + * the rights to use, copy, modify, merge, publish, distribute, sublicense,
> + * and/or sell copies of the Software, and to permit persons to whom the
> + * Software is furnished to do so, subject to the following conditions:
> + *
> + * The above copyright notice and this permission notice shall be included in
> + * all copies or substantial portions of the Software.
> + *
> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
> + * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
> + * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
> + * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
> + * OTHER DEALINGS IN THE SOFTWARE.
> + *
> + */
> +#ifndef _AMDGPU_CTX_WL_H_
> +#define _AMDGPU_CTX_WL_H_
> +#include <drm/amdgpu_drm.h>
> +#include "amdgpu.h"
> +
> +/* Workload mode names */
> +static const char * const amdgpu_workload_mode_name[] = {
> +	"None",
> +	"3D",
> +	"Video",
> +	"VR",
> +	"Compute",
> +	"Unknown",
> +};
> +
> +static inline const
> +char *amdgpu_workload_profile_name(uint32_t profile)
> +{
> +	if (profile >= AMDGPU_CTX_WORKLOAD_HINT_NONE &&
> +		profile < AMDGPU_CTX_WORKLOAD_HINT_MAX)
> +		return amdgpu_workload_mode_name[AMDGPU_CTX_WORKLOAD_INDEX(profile)];
> +
> +	return amdgpu_workload_mode_name[AMDGPU_CTX_WORKLOAD_HINT_MAX];
> +}
> +
> +int amdgpu_clear_workload_profile(struct amdgpu_device *adev,
> +				uint32_t hint);
> +
> +int amdgpu_set_workload_profile(struct amdgpu_device *adev,
> +				uint32_t hint);
> +
> +#endif
> diff --git a/drivers/gpu/drm/amd/pm/inc/amdgpu_dpm.h b/drivers/gpu/drm/amd/pm/inc/amdgpu_dpm.h
> index 65624d091ed2..565131f789d0 100644
> --- a/drivers/gpu/drm/amd/pm/inc/amdgpu_dpm.h
> +++ b/drivers/gpu/drm/amd/pm/inc/amdgpu_dpm.h
> @@ -361,6 +361,11 @@ struct amdgpu_pm {
>   	struct mutex            stable_pstate_ctx_lock;
>   	struct amdgpu_ctx       *stable_pstate_ctx;
>   
> +	/* SMU workload mode */
> +	struct mutex smu_workload_lock;
> +	uint32_t workload_mode;
> +	atomic_t workload_switch_ref;
> +
>   	struct config_table_setting config_table;
>   	/* runtime mode */
>   	enum amdgpu_runpm_mode rpm_mode;
>