Re: [PATCH 10/10] drm/xe/sriov: Add debugfs to set EQ and PT for scheduler groups

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

On 11/27/2025 2:45 AM, Daniele Ceraolo Spurio wrote:
> A top-level debugfs file is added that allows a user to provide a
> comma-separated list of values to assign to each group. Per-group files

it doesn't need to be comma-separated list, just array of integers

> are also added to allow individual tuning of a specific group.
> 
> Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
> Cc: Michal Wajdeczko <michal.wajdeczko@intel.com>
> ---
>  drivers/gpu/drm/xe/xe_gt_sriov_pf_debugfs.c | 173 +++++++++++++++++++-
>  1 file changed, 168 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/gpu/drm/xe/xe_gt_sriov_pf_debugfs.c b/drivers/gpu/drm/xe/xe_gt_sriov_pf_debugfs.c
> index 947e2b92d58a..052510736017 100644
> --- a/drivers/gpu/drm/xe/xe_gt_sriov_pf_debugfs.c
> +++ b/drivers/gpu/drm/xe/xe_gt_sriov_pf_debugfs.c
> @@ -165,24 +165,169 @@ static void pf_add_policy_attrs(struct xe_gt *gt, struct dentry *parent)
>   *              :   ├── gt0
>   *                  :   ├── sched_groups_mode
>   *                      ├── sched_groups
> - *                      :   ├── group0
> - *                          :   └── engines
> + *                      :   ├── exec_quantums_ms
> + *                          ├── preempt_timeouts_us
> + *                          ├── group0
> + *                          :   ├── engines
> + *                              ├── exec_quantum_ms
> + *                              └── preempt_timeout_us

as already commented, per-group EQ/PT are overkill

let just keep array-variants

    *                      ├── sched_groups_exec_quantums_ms
    *                      ├── sched_groups_preempt_timeouts_us

and regular files for groups to show configured engines (if any)

    *                      ├── sched_groups/
    *                          ├── group0
    *                          ├── group1

>   *                          :
>   *                          └── groupN
> - *          :                   └── engines
> + *                              ├── engines
> + *                              ├── exec_quantum_ms
> + *          :                   └── preempt_timeout_us
>   *          ├── vf1
>   *          :   ├── tile0
>   *              :   ├── gt0
>   *                  :   ├── sched_groups
> - *                      :   ├── group0
> - *                          :   └── engines
> + *                      :   ├── exec_quantums_ms
> + *                          ├── preempt_timeouts_us
> + *                          ├── group0
> + *                          :   ├── engines
> + *                              ├── exec_quantum_ms
> + *                              └── preempt_timeout_us
>   */
>  
>  struct sched_group_info {
>  	struct xe_gt *gt;
> +	unsigned int vfid;
> +	u8 group_id;
>  	u32 *masks;
>  };
>  
> +static int sched_groups_config_show(struct seq_file *m, void *data,
> +				    void (*get)(struct xe_gt *, unsigned int, u32 *, u32))
> +{
> +	u32 values[GUC_KLV_VGT_POLICY_ENGINE_GROUP_MAX_COUNT];
> +	struct drm_printer p = drm_seq_file_printer(m);
> +	struct sched_group_info *groups = m->private;
> +	struct xe_gt *gt = groups[0].gt;
> +	unsigned int vfid = groups[0].vfid;
> +	bool first = true;
> +	u8 g;
> +
> +	get(gt, vfid, values, ARRAY_SIZE(values));
> +
> +	for (g = 0; g < ARRAY_SIZE(values); g++) {
> +		drm_printf(&p, "%s%u", first ? "" : ",", values[g]);

maybe we should print values without commas ?

	20 20 30

it's more likely to be accepted when we promote that to sysfs

> +
> +		first = false;
> +	}
> +
> +	drm_printf(&p, "\n");
> +
> +	return 0;
> +}
> +
> +#define MAX_EGS_ARRAY_SIZE (GUC_KLV_VGT_POLICY_ENGINE_GROUP_MAX_COUNT * sizeof(u32))
> +static ssize_t sched_groups_config_write(struct file *file, const char __user *ubuf,
> +					 size_t size, loff_t *pos,
> +					 int (*set)(struct xe_gt *, unsigned int, u32 *, u32))
> +{
> +	struct sched_group_info *groups = file_inode(file)->i_private;
> +	u32 values[GUC_KLV_VGT_POLICY_ENGINE_GROUP_MAX_COUNT];
> +	struct xe_gt *gt = groups[0].gt;
> +	unsigned int vfid = groups[0].vfid;
> +	int *input;
> +	u32 count;
> +	int ret;
> +	int i;
> +
> +	if (*pos)
> +		return -ESPIPE;
> +
> +	if (!size)
> +		return -ENODATA;
> +
> +	ret = parse_int_array_user(ubuf, min(size, MAX_EGS_ARRAY_SIZE), &input);
> +	if (ret)
> +		return ret;
> +
> +	count = input[0];

need to check against GUC_MAX_GROUPS

> +	for (i = 0; i < count; i++) {
> +		if (input[i + 1] < 0 || input[i + 1] > S32_MAX) {
> +			ret = -EINVAL;
> +			goto out;
> +		}
> +
> +		values[i] = input[i + 1];
> +	}
> +
> +	xe_pm_runtime_get(gt_to_xe(gt));
> +	ret = set(gt, vfid, values, count);
> +	xe_pm_runtime_put(gt_to_xe(gt));
> +
> +out:
> +	kfree(input);
> +	return (ret < 0) ? ret : size;
> +}
> +
> +#define DEFINE_SRIOV_GT_GRP_CFG_DEBUGFS_ATTRIBUTE(CONFIG, TYPE, FORMAT)		\
> +static int sched_groups_##CONFIG##s_show(struct seq_file *m,			\
> +						  void *data)			\
> +{										\
> +	return sched_groups_config_show(m, data,				\
> +					xe_gt_sriov_pf_config_get_groups_##CONFIG##s); \
> +}										\
> +										\
> +static int sched_groups_##CONFIG##s_open(struct inode *inode, struct file *file)\
> +{										\
> +	return single_open(file, sched_groups_##CONFIG##s_show,			\
> +			   inode->i_private);					\
> +}										\
> +										\
> +static ssize_t sched_groups_##CONFIG##s_write(struct file *file,		\
> +					      const char __user *ubuf,		\
> +					      size_t size, loff_t *pos)		\
> +{										\
> +	return sched_groups_config_write(file, ubuf, size, pos,			\
> +					 xe_gt_sriov_pf_config_set_groups_##CONFIG##s); \
> +}										\
> +										\
> +static const struct file_operations sched_groups_##CONFIG##s_fops = {		\
> +	.owner = THIS_MODULE,							\
> +	.open = sched_groups_##CONFIG##s_open,					\
> +	.read = seq_read,							\
> +	.llseek = seq_lseek,							\
> +	.write = sched_groups_##CONFIG##s_write,				\
> +	.release = single_release,						\
> +};										\
> +										\
> +static int group_##CONFIG##_set(void *data, u64 val)				\
> +{										\
> +	struct sched_group_info *gi = data;					\
> +	struct xe_device *xe = gt_to_xe(gi->gt);				\
> +	int err;								\
> +										\
> +	if (val > (TYPE)~0ull)							\
> +		return -EOVERFLOW;						\
> +										\
> +	xe_pm_runtime_get(xe);							\
> +	err = xe_sriov_pf_wait_ready(xe) ?:					\
> +	      xe_gt_sriov_pf_config_set_group_##CONFIG(gi->gt, gi->vfid,	\
> +						       gi->group_id, val);	\
> +	if (!err)								\
> +		xe_sriov_pf_provision_set_custom_mode(xe);			\
> +	xe_pm_runtime_put(xe);							\
> +										\
> +	return err;								\
> +}										\
> +										\
> +static int group_##CONFIG##_get(void *data, u64 *val)				\
> +{										\
> +	struct sched_group_info *gi = data;					\
> +										\
> +	*val = xe_gt_sriov_pf_config_get_group_##CONFIG(gi->gt, gi->vfid,	\
> +							gi->group_id);		\
> +	return 0;								\
> +}										\
> +										\
> +DEFINE_DEBUGFS_ATTRIBUTE(group_##CONFIG##_fops, group_##CONFIG##_get,		\
> +			 group_##CONFIG##_set, FORMAT)
> +
> +DEFINE_SRIOV_GT_GRP_CFG_DEBUGFS_ATTRIBUTE(exec_quantum, u32, "%llu\n");
> +DEFINE_SRIOV_GT_GRP_CFG_DEBUGFS_ATTRIBUTE(preempt_timeout, u32, "%llu\n");
> +
>  static int sched_group_engines_info(struct seq_file *m, void *data)
>  {
>  	struct drm_printer p = drm_seq_file_printer(m);
> @@ -261,6 +406,18 @@ static void sched_group_info_register(struct xe_gt *gt, unsigned int vfid)
>  		goto out_err;
>  	parent->d_inode->i_private = infos;
>  
> +	/*
> +	 * assign group 0 gt and VF id values early as they're used by the
> +	 * exec_quantums debugfs to set quantums for all groups
> +	 */
> +	infos[0].gt = gt;
> +	infos[0].vfid = vfid;
> +
> +	debugfs_create_file("exec_quantums_ms", 0644, parent, infos,
> +			    &sched_groups_exec_quantums_fops);
> +	debugfs_create_file("preempt_timeouts_us", 0644, parent, infos,
> +			    &sched_groups_preempt_timeouts_fops);
> +
>  	for (g = 0; g < num_groups; g++) {
>  		struct sched_group_info *info = &infos[g];
>  		u32 base = g * GUC_MAX_ENGINE_CLASSES;
> @@ -273,10 +430,16 @@ static void sched_group_info_register(struct xe_gt *gt, unsigned int vfid)
>  			goto out_err;
>  
>  		info->gt = gt;
> +		info->vfid = vfid;
> +		info->group_id = g;
>  		info->masks = &policy->guc.sched_groups.modes[mode].masks[base];
>  
>  		dent->d_inode->i_private = info;
>  		debugfs_create_file("engines", 0644, dent, info, &sched_group_engines_fops);
> +		debugfs_create_file("exec_quantum_ms", 0644, dent, info,
> +				    &group_exec_quantum_fops);
> +		debugfs_create_file("preempt_timeout_us", 0644, dent, info,
> +				    &group_preempt_timeout_fops);
>  	}
>  
>  	return;