Re: [Freedreno] [PATCH 2/2] drm/msm: Add param for userspace to query suspend count

From: Jordan Crouse <jordan@cosmicpenguin.net>
To: Rob Clark <robdclark@gmail.com>
Cc: dri-devel@lists.freedesktop.org,
	Rob Clark <robdclark@chromium.org>,
	"open list:DRM DRIVER FOR MSM ADRENO GPU" 
	<freedreno@lists.freedesktop.org>,
	Jonathan Marek <jonathan@marek.ca>,
	David Airlie <airlied@linux.ie>,
	"open list:DRM DRIVER FOR MSM ADRENO GPU" 
	<linux-arm-msm@vger.kernel.org>,
	Sharat Masetty <smasetty@codeaurora.org>,
	Konrad Dybcio <konrad.dybcio@somainline.org>,
	Jordan Crouse <jcrouse@codeaurora.org>,
	Bjorn Andersson <bjorn.andersson@linaro.org>,
	Akhil P Oommen <akhilpo@codeaurora.org>,
	Daniel Vetter <daniel@ffwll.ch>, Dave Airlie <airlied@redhat.com>,
	Sean Paul <sean@poorly.run>,
	open list <linux-kernel@vger.kernel.org>
Subject: Re: [Freedreno] [PATCH 2/2] drm/msm: Add param for userspace to query suspend count
Date: Fri, 2 Apr 2021 08:50:51 -0600	[thread overview]
Message-ID: <20210402145051.jcs23ssgkqkkmmtq@cosmicpenguin.net> (raw)
In-Reply-To: <20210325012358.1759770-3-robdclark@gmail.com>

On Wed, Mar 24, 2021 at 06:23:53PM -0700, Rob Clark wrote:
> From: Rob Clark <robdclark@chromium.org>
> 
> Performance counts, and ALWAYS_ON counters used for capturing GPU
> timestamps, lose their state across suspend/resume cycles.  Userspace
> tooling for performance monitoring needs to be aware of this.  For
> example, after a suspend userspace needs to recalibrate it's offset
> between CPU and GPU time.
> 

Acked-by: Jordan Crouse <jordan@cosmicpenguin.net>

> Signed-off-by: Rob Clark <robdclark@chromium.org>
> ---
>  drivers/gpu/drm/msm/adreno/adreno_gpu.c | 3 +++
>  drivers/gpu/drm/msm/msm_drv.c           | 1 +
>  drivers/gpu/drm/msm/msm_gpu.c           | 2 ++
>  drivers/gpu/drm/msm/msm_gpu.h           | 2 ++
>  include/uapi/drm/msm_drm.h              | 1 +
>  5 files changed, 9 insertions(+)
> 
> diff --git a/drivers/gpu/drm/msm/adreno/adreno_gpu.c b/drivers/gpu/drm/msm/adreno/adreno_gpu.c
> index f09175698827..e473b7c9ff7f 100644
> --- a/drivers/gpu/drm/msm/adreno/adreno_gpu.c
> +++ b/drivers/gpu/drm/msm/adreno/adreno_gpu.c
> @@ -280,6 +280,9 @@ int adreno_get_param(struct msm_gpu *gpu, uint32_t param, uint64_t *value)
>  	case MSM_PARAM_FAULTS:
>  		*value = gpu->global_faults;
>  		return 0;
> +	case MSM_PARAM_SUSPENDS:
> +		*value = gpu->suspend_count;
> +		return 0;
>  	default:
>  		DBG("%s: invalid param: %u", gpu->name, param);
>  		return -EINVAL;
> diff --git a/drivers/gpu/drm/msm/msm_drv.c b/drivers/gpu/drm/msm/msm_drv.c
> index b29e439eb299..4f9fa0189a07 100644
> --- a/drivers/gpu/drm/msm/msm_drv.c
> +++ b/drivers/gpu/drm/msm/msm_drv.c
> @@ -39,6 +39,7 @@
>   *           GEM object's debug name
>   * - 1.5.0 - Add SUBMITQUERY_QUERY ioctl
>   * - 1.6.0 - Syncobj support
> + * - 1.7.0 - Add MSM_PARAM_SUSPENDS to access suspend count
>   */
>  #define MSM_VERSION_MAJOR	1
>  #define MSM_VERSION_MINOR	6
> diff --git a/drivers/gpu/drm/msm/msm_gpu.c b/drivers/gpu/drm/msm/msm_gpu.c
> index 7bdb01f202f4..ab888d83b887 100644
> --- a/drivers/gpu/drm/msm/msm_gpu.c
> +++ b/drivers/gpu/drm/msm/msm_gpu.c
> @@ -256,6 +256,8 @@ int msm_gpu_pm_suspend(struct msm_gpu *gpu)
>  	if (ret)
>  		return ret;
>  
> +	gpu->suspend_count++;
> +
>  	return 0;
>  }
>  
> diff --git a/drivers/gpu/drm/msm/msm_gpu.h b/drivers/gpu/drm/msm/msm_gpu.h
> index d7cd02cd2109..18baf935e143 100644
> --- a/drivers/gpu/drm/msm/msm_gpu.h
> +++ b/drivers/gpu/drm/msm/msm_gpu.h
> @@ -152,6 +152,8 @@ struct msm_gpu {
>  		ktime_t time;
>  	} devfreq;
>  
> +	uint32_t suspend_count;
> +
>  	struct msm_gpu_state *crashstate;
>  	/* True if the hardware supports expanded apriv (a650 and newer) */
>  	bool hw_apriv;
> diff --git a/include/uapi/drm/msm_drm.h b/include/uapi/drm/msm_drm.h
> index a6c1f3eb2623..5596d7c37f9e 100644
> --- a/include/uapi/drm/msm_drm.h
> +++ b/include/uapi/drm/msm_drm.h
> @@ -76,6 +76,7 @@ struct drm_msm_timespec {
>  #define MSM_PARAM_NR_RINGS   0x07
>  #define MSM_PARAM_PP_PGTABLE 0x08  /* => 1 for per-process pagetables, else 0 */
>  #define MSM_PARAM_FAULTS     0x09
> +#define MSM_PARAM_SUSPENDS   0x0a
>  
>  struct drm_msm_param {
>  	__u32 pipe;           /* in, MSM_PIPE_x */
> -- 
> 2.29.2
> 
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