[PATCH v2] drm/xe: Add stats for vma page faults

[Cavitt, Jonathan]

-----Original Message-----
From: Intel-xe <intel-xe-bounces at lists.freedesktop.org> On Behalf Of Francois Dugast
Sent: Thursday, February 6, 2025 5:46 AM
To: intel-xe at lists.freedesktop.org
Cc: Dugast, Francois <francois.dugast at intel.com>
Subject: [PATCH v2] drm/xe: Add stats for vma page faults
> 
> Add new entries in stats for vma page faults. If CONFIG_DEBUG_FS is
> enabled, the count and number of bytes can be viewed per GT in the
> stat debugfs file. This helps when testing, to confirm page faults
> have been triggered as expected. It also helps when looking at the
> performance impact of page faults. Data is simply collected when
> entering the page fault handler so there is no indication whether
> it completed successfully, with or without retries, etc.
> 
> Example output:
> 
>     cat /sys/kernel/debug/dri/0/gt0/stats
>     tlb_inval_count: 129
>     vma_pagefault_count: 12
>     vma_pagefault_bytes: 98304
> 
> v2: Rebase
> 
> Signed-off-by: Francois Dugast <francois.dugast at intel.com>

LGTM.
Reviewed-by: Jonathan Cavitt <jonathan.cavitt at intel.com>
-Jonathan Cavitt

> ---
>  drivers/gpu/drm/xe/xe_gt_pagefault.c   | 10 +++++++---
>  drivers/gpu/drm/xe/xe_gt_stats.c       |  2 ++
>  drivers/gpu/drm/xe/xe_gt_stats_types.h |  2 ++
>  3 files changed, 11 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/gpu/drm/xe/xe_gt_pagefault.c b/drivers/gpu/drm/xe/xe_gt_pagefault.c
> index cb92fb5cbc75..46701ca11ce0 100644
> --- a/drivers/gpu/drm/xe/xe_gt_pagefault.c
> +++ b/drivers/gpu/drm/xe/xe_gt_pagefault.c
> @@ -14,6 +14,7 @@
>  #include "abi/guc_actions_abi.h"
>  #include "xe_bo.h"
>  #include "xe_gt.h"
> +#include "xe_gt_stats.h"
>  #include "xe_gt_tlb_invalidation.h"
>  #include "xe_guc.h"
>  #include "xe_guc_ct.h"
> @@ -124,16 +125,20 @@ static int xe_pf_begin(struct drm_exec *exec, struct xe_vma *vma,
>  	return 0;
>  }
>  
> -static int handle_vma_pagefault(struct xe_tile *tile, struct pagefault *pf,
> +static int handle_vma_pagefault(struct xe_gt *gt, struct pagefault *pf,
>  				struct xe_vma *vma)
>  {
>  	struct xe_vm *vm = xe_vma_vm(vma);
> +	struct xe_tile *tile = gt_to_tile(gt);
>  	struct drm_exec exec;
>  	struct dma_fence *fence;
>  	ktime_t end = 0;
>  	int err;
>  	bool atomic;
>  
> +	xe_gt_stats_incr(gt, XE_GT_STATS_ID_VMA_PAGEFAULT_COUNT, 1);
> +	xe_gt_stats_incr(gt, XE_GT_STATS_ID_VMA_PAGEFAULT_BYTES, xe_vma_size(vma));
> +
>  	trace_xe_vma_pagefault(vma);
>  	atomic = access_is_atomic(pf->access_type);
>  
> @@ -202,7 +207,6 @@ static struct xe_vm *asid_to_vm(struct xe_device *xe, u32 asid)
>  static int handle_pagefault(struct xe_gt *gt, struct pagefault *pf)
>  {
>  	struct xe_device *xe = gt_to_xe(gt);
> -	struct xe_tile *tile = gt_to_tile(gt);
>  	struct xe_vm *vm;
>  	struct xe_vma *vma = NULL;
>  	int err;
> @@ -231,7 +235,7 @@ static int handle_pagefault(struct xe_gt *gt, struct pagefault *pf)
>  		goto unlock_vm;
>  	}
>  
> -	err = handle_vma_pagefault(tile, pf, vma);
> +	err = handle_vma_pagefault(gt, pf, vma);
>  
>  unlock_vm:
>  	if (!err)
> diff --git a/drivers/gpu/drm/xe/xe_gt_stats.c b/drivers/gpu/drm/xe/xe_gt_stats.c
> index 7a6c1d808e41..2e9879ea4674 100644
> --- a/drivers/gpu/drm/xe/xe_gt_stats.c
> +++ b/drivers/gpu/drm/xe/xe_gt_stats.c
> @@ -28,6 +28,8 @@ void xe_gt_stats_incr(struct xe_gt *gt, const enum xe_gt_stats_id id, int incr)
>  
>  static const char *const stat_description[__XE_GT_STATS_NUM_IDS] = {
>  	"tlb_inval_count",
> +	"vma_pagefault_count",
> +	"vma_pagefault_bytes",
>  };
>  
>  /**
> diff --git a/drivers/gpu/drm/xe/xe_gt_stats_types.h b/drivers/gpu/drm/xe/xe_gt_stats_types.h
> index 2fc055e39f27..b072bd80c4b9 100644
> --- a/drivers/gpu/drm/xe/xe_gt_stats_types.h
> +++ b/drivers/gpu/drm/xe/xe_gt_stats_types.h
> @@ -8,6 +8,8 @@
>  
>  enum xe_gt_stats_id {
>  	XE_GT_STATS_ID_TLB_INVAL,
> +	XE_GT_STATS_ID_VMA_PAGEFAULT_COUNT,
> +	XE_GT_STATS_ID_VMA_PAGEFAULT_BYTES,
>  	/* must be the last entry */
>  	__XE_GT_STATS_NUM_IDS,
>  };
> -- 
> 2.43.0
> 
>