Re: [PATCH v5 1/2] drm/xe: Add clearing stats to GT debugfs

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

On 8/27/2025 8:43 PM, Matthew Brost wrote:
> It helpful to clear GT stats, run a test cases which is being profiled,
> and look at the results of the stats from the individual test case. Make
> stats entry writable and upon write clear the stats.
> 
> v5:
>  - Drop clear_stats debugfs entry (Lucas)
> 
> Signed-off-by: Matthew Brost <matthew.brost@intel.com>
> ---
>  drivers/gpu/drm/xe/xe_gt_debugfs.c | 25 ++++++++++++++++++++++++-
>  drivers/gpu/drm/xe/xe_gt_stats.c   | 14 ++++++++++++++
>  drivers/gpu/drm/xe/xe_gt_stats.h   |  1 +
>  3 files changed, 39 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/xe/xe_gt_debugfs.c b/drivers/gpu/drm/xe/xe_gt_debugfs.c
> index bf3a67b5951c..0004f279dee1 100644
> --- a/drivers/gpu/drm/xe/xe_gt_debugfs.c
> +++ b/drivers/gpu/drm/xe/xe_gt_debugfs.c
> @@ -327,7 +327,6 @@ static const struct drm_info_list vf_safe_debugfs_list[] = {
>  	{"default_lrc_bcs", .show = xe_gt_debugfs_simple_show, .data = bcs_default_lrc},
>  	{"default_lrc_vcs", .show = xe_gt_debugfs_simple_show, .data = vcs_default_lrc},
>  	{"default_lrc_vecs", .show = xe_gt_debugfs_simple_show, .data = vecs_default_lrc},
> -	{"stats", .show = xe_gt_debugfs_simple_show, .data = xe_gt_stats_print_info},
>  	{"hwconfig", .show = xe_gt_debugfs_simple_show, .data = hwconfig},
>  };
>  
> @@ -363,6 +362,29 @@ static ssize_t write_to_gt_call(const char __user *userbuf, size_t count, loff_t
>  	return count;
>  }
>  
> +static void clear_stats(struct xe_gt *gt)
> +{
> +	xe_gt_stats_clear(gt);
> +}

not needed - see below

> +
> +static ssize_t stats_write(struct file *file, const char __user *userbuf,
> +			   size_t count, loff_t *ppos)
> +{
> +	struct seq_file *s = file->private_data;
> +	struct xe_gt *gt = s->private;
> +
> +	return write_to_gt_call(userbuf, count, ppos, clear_stats, gt);

why not pass the xe_gt_stats_clear() directly here? it's the same signature

> +}
> +
> +static int stats_show(struct seq_file *s, void *unused)
> +{
> +	struct drm_printer p = drm_seq_file_printer(s);
> +	struct xe_gt *gt = s->private;
> +
> +	return xe_gt_stats_print_info(gt, &p);
> +}
> +DEFINE_SHOW_STORE_ATTRIBUTE(stats);
> +
>  static void force_reset(struct xe_gt *gt)
>  {
>  	struct xe_device *xe = gt_to_xe(gt);
> @@ -448,6 +470,7 @@ void xe_gt_debugfs_register(struct xe_gt *gt)
>  	root->d_inode->i_private = gt;
>  
>  	/* VF safe */
> +	debugfs_create_file("stats", 0600, root, gt, &stats_fops);
>  	debugfs_create_file("force_reset", 0600, root, gt, &force_reset_fops);
>  	debugfs_create_file("force_reset_sync", 0600, root, gt, &force_reset_sync_fops);
>  
> diff --git a/drivers/gpu/drm/xe/xe_gt_stats.c b/drivers/gpu/drm/xe/xe_gt_stats.c
> index 30f942671c2b..7e12fc3759e2 100644
> --- a/drivers/gpu/drm/xe/xe_gt_stats.c
> +++ b/drivers/gpu/drm/xe/xe_gt_stats.c
> @@ -50,3 +50,17 @@ int xe_gt_stats_print_info(struct xe_gt *gt, struct drm_printer *p)
>  
>  	return 0;
>  }
> +
> +/**
> + * xe_gt_stats_clear - Clear the GT stats
> + * @gt: GT structure
> + *
> + * This clear (zeros) all the available GT stats.
> + */
> +void xe_gt_stats_clear(struct xe_gt *gt)
> +{
> +	enum xe_gt_stats_id id;

I would just use "int" as we don't really use enum here

> +
> +	for (id = 0; id < __XE_GT_STATS_NUM_IDS; ++id)

or even maybe we can just go from 0 to ARRAY_SIZE(gt->stats.counters) ?

> +		atomic64_set(&gt->stats.counters[id], 0);
> +}
> diff --git a/drivers/gpu/drm/xe/xe_gt_stats.h b/drivers/gpu/drm/xe/xe_gt_stats.h
> index 38325ef53617..e8aea32bc971 100644
> --- a/drivers/gpu/drm/xe/xe_gt_stats.h
> +++ b/drivers/gpu/drm/xe/xe_gt_stats.h
> @@ -13,6 +13,7 @@ struct drm_printer;
>  
>  #ifdef CONFIG_DEBUG_FS
>  int xe_gt_stats_print_info(struct xe_gt *gt, struct drm_printer *p);
> +void xe_gt_stats_clear(struct xe_gt *gt);
>  void xe_gt_stats_incr(struct xe_gt *gt, const enum xe_gt_stats_id id, int incr);
>  #else
>  static inline void