>
> Instead of polling for tail to be updated, use wfe instruction.
>
> 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 | 4 ++--
> lib/librte_ring/rte_ring_generic.h | 3 +--
> 2 files changed, 3 insertions(+), 4 deletions(-)
>
> diff --git a/lib/librte_ring/rte_ring_c11_mem.h
> b/lib/librte_ring/rte_ring_c11_mem.h
> index 0fb73a337..764d8f186 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 +22,7 @@ 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();
> + rte_wait_until_equal_relaxed_32(&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 953cdbbd5..682852783 100644
> --- a/lib/librte_ring/rte_ring_generic.h
> +++ b/lib/librte_ring/rte_ring_generic.h
> @@ -23,8 +23,7 @@ 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();
> + rte_wait_until_equal_relaxed_32(&ht->tail, old_val);
./lib/librte_ring/rte_ring_generic.h:26:3: error: implicit declaration of
function 'rte_wait_until_equal_relaxed_32'; did you mean
'rte_wait_until_equal_32'? [-Werror=implicit-function-declaration]
rte_wait_until_equal_relaxed_32(&ht->tail, old_val);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
BTW, after patch #1 compilation fails also:
../lib/librte_eal/x86/include/rte_spinlock.h:125:24: error: pointer targets in
passing argument 1 of 'rte_try_tm' differ in signedness [-Werror=pointer-sign]
if (likely(rte_try_tm(&sl->locked)))
^
>
> ht->tail = new_val;
> }
> --
> 2.17.1
