[PATCH v2 09/12] drm/xe: Add pagefault chaining stats

[Matthew Brost <matthew.brost@intel.com>]

Add GT stats to quantify pagefault chaining behavior during fault storms.

Track total chained faults, faults chained directly from the IRQ
handler, cases where IRQ chaining also drained the queue, chained faults
that had to be requeued due to range mismatch, and cases where the last
serviced range allowed immediate ack.

Signed-off-by: Matthew Brost <matthew.brost@intel.com>
---
 drivers/gpu/drm/xe/xe_gt_stats.c       |  5 +++++
 drivers/gpu/drm/xe/xe_gt_stats_types.h |  5 +++++
 drivers/gpu/drm/xe/xe_pagefault.c      | 18 ++++++++++++++++--
 3 files changed, 26 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/xe/xe_gt_stats.c b/drivers/gpu/drm/xe/xe_gt_stats.c
index c1af3ecb429b..cdd467dfb46d 100644
--- a/drivers/gpu/drm/xe/xe_gt_stats.c
+++ b/drivers/gpu/drm/xe/xe_gt_stats.c
@@ -54,6 +54,11 @@ void xe_gt_stats_incr(struct xe_gt *gt, const enum xe_gt_stats_id id, int incr)
 #define DEF_STAT_STR(ID, name) [XE_GT_STATS_ID_##ID] = name
 
 static const char *const stat_description[__XE_GT_STATS_NUM_IDS] = {
+	DEF_STAT_STR(CHAIN_PAGEFAULT_COUNT, "chain_pagefault_count"),
+	DEF_STAT_STR(CHAIN_IRQ_PAGEFAULT_COUNT, "chain_irq_pagefault_count"),
+	DEF_STAT_STR(CHAIN_DRAIN_IRQ_PAGEFAULT_COUNT, "chain_drain_irq_pagefault_count"),
+	DEF_STAT_STR(CHAIN_MISMATCH_PAGEFAULT_COUNT, "chain_mismatch_pagefault_count"),
+	DEF_STAT_STR(LAST_PAGEFAULT_COUNT, "last_pagefault_count"),
 	DEF_STAT_STR(SVM_PAGEFAULT_COUNT, "svm_pagefault_count"),
 	DEF_STAT_STR(TLB_INVAL, "tlb_inval_count"),
 	DEF_STAT_STR(SVM_TLB_INVAL_COUNT, "svm_tlb_inval_count"),
diff --git a/drivers/gpu/drm/xe/xe_gt_stats_types.h b/drivers/gpu/drm/xe/xe_gt_stats_types.h
index 129260bfdfe6..591e614e1cfc 100644
--- a/drivers/gpu/drm/xe/xe_gt_stats_types.h
+++ b/drivers/gpu/drm/xe/xe_gt_stats_types.h
@@ -9,6 +9,11 @@
 #include <linux/types.h>
 
 enum xe_gt_stats_id {
+	XE_GT_STATS_ID_CHAIN_PAGEFAULT_COUNT,
+	XE_GT_STATS_ID_CHAIN_IRQ_PAGEFAULT_COUNT,
+	XE_GT_STATS_ID_CHAIN_DRAIN_IRQ_PAGEFAULT_COUNT,
+	XE_GT_STATS_ID_CHAIN_MISMATCH_PAGEFAULT_COUNT,
+	XE_GT_STATS_ID_LAST_PAGEFAULT_COUNT,
 	XE_GT_STATS_ID_SVM_PAGEFAULT_COUNT,
 	XE_GT_STATS_ID_TLB_INVAL,
 	XE_GT_STATS_ID_SVM_TLB_INVAL_COUNT,
diff --git a/drivers/gpu/drm/xe/xe_pagefault.c b/drivers/gpu/drm/xe/xe_pagefault.c
index 9c14f9505faf..c497dd8d9724 100644
--- a/drivers/gpu/drm/xe/xe_pagefault.c
+++ b/drivers/gpu/drm/xe/xe_pagefault.c
@@ -364,6 +364,7 @@ xe_pagefault_queue_requeue(struct xe_pagefault_queue *pf_queue,
 					    usm.pf_queue);
 	struct xe_pagefault *next = pf->consumer.next, *lpf;
 
+	xe_gt_stats_incr(gt, XE_GT_STATS_ID_CHAIN_MISMATCH_PAGEFAULT_COUNT, 1);
 	xe_assert(xe, pf->consumer.alloc_state ==
 		  XE_PAGEFAULT_ALLOC_STATE_CHAINED);
 
@@ -423,6 +424,10 @@ static bool xe_pagefault_cache_hit(struct xe_pagefault_queue *pf_queue,
 			xe_assert(xe, pf_work->cache.pf->consumer.alloc_state ==
 				  XE_PAGEFAULT_ALLOC_STATE_ACTIVE);
 
+			xe_gt_stats_incr(pf->gt,
+					 XE_GT_STATS_ID_CHAIN_PAGEFAULT_COUNT,
+					 1);
+
 			pf->consumer.alloc_state =
 				XE_PAGEFAULT_ALLOC_STATE_CHAINED;
 			pf->consumer.next = pf_work->cache.pf->consumer.next;
@@ -559,8 +564,10 @@ static void xe_pagefault_queue_work(struct work_struct *w)
 
 		/* Last fault same address, ack immediately */
 		if (xe_pagefault_cache_match(pf, cache_start, cache_end,
-					     cache_asid))
+					     cache_asid)) {
+			xe_gt_stats_incr(gt, XE_GT_STATS_ID_LAST_PAGEFAULT_COUNT, 1);
 			goto ack_fault;
+		}
 
 		err = xe_pagefault_service(pf);
 
@@ -816,8 +823,15 @@ int xe_pagefault_handler(struct xe_device *xe, struct xe_pagefault *pf)
 		lpf->consumer.next = NULL;
 
 		if (xe_pagefault_cache_hit(pf_queue, lpf)) {
-			if (empty)
+			xe_gt_stats_incr(pf->gt,
+					 XE_GT_STATS_ID_CHAIN_IRQ_PAGEFAULT_COUNT,
+					 1);
+			if (empty) {
 				xe_pagefault_queue_advance(pf_queue);
+				xe_gt_stats_incr(pf->gt,
+						 XE_GT_STATS_ID_CHAIN_DRAIN_IRQ_PAGEFAULT_COUNT,
+						 1);
+			}
 		} else {
 			int work_index = xe_pagefault_work_index(xe);
 
-- 
2.34.1