Instead of polling for tail to be updated, use wfe instruction.
50%~70% performance gain was measured by running ring_perf_autotest on
ThunderX2.
Signed-off-by: Gavin Hu <gavin...@arm.com>
Reviewed-by: Ruifeng Wang <ruifeng.w...@arm.com>
Reviewed-by: Steve Capper <steve.cap...@arm.com>
Reviewed-by: Ola Liljedahl <ola.liljed...@arm.com>
Reviewed-by: Honnappa Nagarahalli <honnappa.nagaraha...@arm.com>
---
lib/librte_ring/rte_ring_c11_mem.h | 5 +++--
lib/librte_ring/rte_ring_generic.h | 4 ++--
2 files changed, 5 insertions(+), 4 deletions(-)
diff --git a/lib/librte_ring/rte_ring_c11_mem.h
b/lib/librte_ring/rte_ring_c11_mem.h
index 0fb73a3..f1de79c 100644
--- a/lib/librte_ring/rte_ring_c11_mem.h
+++ b/lib/librte_ring/rte_ring_c11_mem.h
@@ -2,6 +2,7 @@
*
* Copyright (c) 2017,2018 HXT-semitech Corporation.
* Copyright (c) 2007-2009 Kip Macy km...@freebsd.org
+ * Copyright (c) 2019 Arm Limited
* All rights reserved.
* Derived from FreeBSD's bufring.h
* Used as BSD-3 Licensed with permission from Kip Macy.
@@ -21,8 +22,8 @@ update_tail(struct rte_ring_headtail *ht, uint32_t old_val,
uint32_t new_val,
* we need to wait for them to complete
*/
if (!single)
- while (unlikely(ht->tail != old_val))
- rte_pause();
+ if (unlikely(ht->tail != old_val))
+ rte_wait_until_equal_relaxed(&ht->tail, old_val);
__atomic_store_n(&ht->tail, new_val, __ATOMIC_RELEASE);
}
diff --git a/lib/librte_ring/rte_ring_generic.h
b/lib/librte_ring/rte_ring_generic.h
index 953cdbb..bb0dce0 100644
--- a/lib/librte_ring/rte_ring_generic.h
+++ b/lib/librte_ring/rte_ring_generic.h
@@ -23,8 +23,8 @@ update_tail(struct rte_ring_headtail *ht, uint32_t old_val,
uint32_t new_val,
* we need to wait for them to complete
*/
if (!single)
- while (unlikely(ht->tail != old_val))
- rte_pause();
+ if (unlikely(ht->tail != old_val))
+ rte_wait_until_equal_relaxed(&ht->tail, old_val);
ht->tail = new_val;
}
--
2.7.4
