[RFC 2/3] event/cnxk: add pause to spinloops

[Stephen Hemminger]

On SMT systems when a spinloop is done without a pause
it may cause excessive latency. This problem was found
by the fix_empty_spinloops coccinelle script.

This is compile tested only! I don't have this hardware.

Signed-off-by: Stephen Hemminger <stephen at networkplumber.org>
---
 drivers/event/cnxk/cn10k_worker.c    | 2 +-
 drivers/event/cnxk/cn20k_worker.c    | 2 +-
 drivers/event/cnxk/cnxk_tim_worker.h | 4 ++--
 3 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/event/cnxk/cn10k_worker.c b/drivers/event/cnxk/cn10k_worker.c
index 80077ec8a1..69ac67115a 100644
--- a/drivers/event/cnxk/cn10k_worker.c
+++ b/drivers/event/cnxk/cn10k_worker.c
@@ -93,7 +93,7 @@ sso_lmt_aw_wait_fc(struct cn10k_sso_hws *ws, int64_t req)
 
 retry:
 	while (rte_atomic_load_explicit(ws->fc_cache_space, rte_memory_order_relaxed) < 0)
-		;
+		rte_pause();
 
 	cached = rte_atomic_fetch_sub_explicit(ws->fc_cache_space, req, rte_memory_order_acquire) -
 		 req;
diff --git a/drivers/event/cnxk/cn20k_worker.c b/drivers/event/cnxk/cn20k_worker.c
index 53daf3b4b0..49dfb2a28c 100644
--- a/drivers/event/cnxk/cn20k_worker.c
+++ b/drivers/event/cnxk/cn20k_worker.c
@@ -93,7 +93,7 @@ sso_lmt_aw_wait_fc(struct cn20k_sso_hws *ws, int64_t req)
 
 retry:
 	while (rte_atomic_load_explicit(ws->fc_cache_space, rte_memory_order_relaxed) < 0)
-		;
+		rte_pause();
 
 	cached = rte_atomic_fetch_sub_explicit(ws->fc_cache_space, req, rte_memory_order_acquire) -
 		 req;
diff --git a/drivers/event/cnxk/cnxk_tim_worker.h b/drivers/event/cnxk/cnxk_tim_worker.h
index 09f84091ab..887c0800e2 100644
--- a/drivers/event/cnxk/cnxk_tim_worker.h
+++ b/drivers/event/cnxk/cnxk_tim_worker.h
@@ -405,9 +405,9 @@ cnxk_tim_add_entry_mp(struct cnxk_tim_ring *const tim_ring,
 			     : [crem] "r"(&bkt->w1)
 			     : "memory");
 #else
-		while (rte_atomic_load_explicit((int64_t __rte_atomic *)&bkt->w1,
+		while (rte_atomic_load_explicit((int64_t __rte_atomic  *)&bkt->w1,
 						rte_memory_order_relaxed) < 0)
-			;
+			rte_pause();
 #endif
 		goto __retry;
 	} else if (!rem) {
-- 
2.51.0