Re: [PATCH 3/3] drm/xe/client: Skip drm-total-cycles if unable to read timestamp

[Michal Wajdeczko <michal.wajdeczko@intel.com>]

On 04.02.2025 19:05, Marcin Bernatowicz wrote:
> Ensure show_run_ticks() only prints drm-total-cycles when timestamp
> retrieval succeeds.
> 
> Signed-off-by: Marcin Bernatowicz <marcin.bernatowicz@linux.intel.com>
> Cc: Lucas De Marchi <lucas.demarchi@intel.com>
> Cc: Michal Wajdeczko <michal.wajdeczko@intel.com>
> Cc: Michał Winiarski <michal.winiarski@intel.com>
> Cc: Umesh Nerlige Ramappa <umesh.nerlige.ramappa@intel.com>
> ---
>  drivers/gpu/drm/xe/xe_drm_client.c | 9 ++++++---
>  1 file changed, 6 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/gpu/drm/xe/xe_drm_client.c b/drivers/gpu/drm/xe/xe_drm_client.c
> index 63f30b6df70b..e5c4f342380e 100644
> --- a/drivers/gpu/drm/xe/xe_drm_client.c
> +++ b/drivers/gpu/drm/xe/xe_drm_client.c
> @@ -323,6 +323,7 @@ static void show_run_ticks(struct drm_printer *p, struct drm_file *file)
>  	struct xe_exec_queue *q;
>  	u64 gpu_timestamp;
>  	unsigned int fw_ref;
> +	int err;
>  
>  	/*
>  	 * Wait for any exec queue going away: their cycles will get updated on
> @@ -350,7 +351,7 @@ static void show_run_ticks(struct drm_printer *p, struct drm_file *file)
>  	}
>  	mutex_unlock(&xef->exec_queue.lock);
>  
> -	gpu_timestamp = xe_hw_engine_read_timestamp(hwe);
> +	err = xe_hw_engine_read_timestamp(hwe, &gpu_timestamp);

can't we just check for !IS_SRIOV_VF here?

>  
>  	xe_force_wake_put(gt_to_fw(hwe->gt), fw_ref);
>  	xe_pm_runtime_put(xe);
> @@ -371,8 +372,10 @@ static void show_run_ticks(struct drm_printer *p, struct drm_file *file)
>  		class_name = xe_hw_engine_class_to_str(class);
>  		drm_printf(p, "drm-cycles-%s:\t%llu\n",
>  			   class_name, xef->run_ticks[class]);
> -		drm_printf(p, "drm-total-cycles-%s:\t%llu\n",
> -			   class_name, gpu_timestamp);
> +
> +		if (!err)
> +			drm_printf(p, "drm-total-cycles-%s:\t%llu\n",

are we sure we don't break any tools that might look for this?

> +				   class_name, gpu_timestamp);
>  
>  		if (capacity[class] > 1)
>  			drm_printf(p, "drm-engine-capacity-%s:\t%lu\n",