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From: Gavin Hu <gavin.hu@arm.com>
To: dev@dpdk.org
Cc: nd@arm.com,
david.marchand@redhat.com,
konstantin.ananyev@intel.com
Date: Mon, 4 Nov 2019 23:32:38 +0800
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Subject: [dpdk-dev] [PATCH v12 3/5] ticketlock: use new API to reduce
contention on aarch64
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While using ticket lock, cores repeatedly poll the lock variable.
This is replaced by rte_wait_until_equal API.
Running ticketlock_autotest on ThunderX2, Ampere eMAG80, and Arm N1SDP[1],
there were variances between runs, but no notable performance gain or
degradation were seen with and without this patch.
[1] https://community.arm.com/developer/tools-software/oss-platforms/w/\
docs/440/neoverse-n1-sdp
Signed-off-by: Gavin Hu <gavin.hu@arm.com>
Reviewed-by: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>
Tested-by: Phil Yang <phil.yang@arm.com>
Tested-by: Pavan Nikhilesh <pbhagavatula@marvell.com>
Reviewed-by: Jerin Jacob <jerinj@marvell.com>
---
lib/librte_eal/common/include/generic/rte_ticketlock.h | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/lib/librte_eal/common/include/generic/rte_ticketlock.h b/lib/librte_eal/common/include/generic/rte_ticketlock.h
index d9bec87..c295ae7 100644
--- a/lib/librte_eal/common/include/generic/rte_ticketlock.h
+++ b/lib/librte_eal/common/include/generic/rte_ticketlock.h
@@ -66,8 +66,7 @@ static inline void
rte_ticketlock_lock(rte_ticketlock_t *tl)
{
uint16_t me = __atomic_fetch_add(&tl->s.next, 1, __ATOMIC_RELAXED);
- while (__atomic_load_n(&tl->s.current, __ATOMIC_ACQUIRE) != me)
- rte_pause();
+ rte_wait_until_equal_16(&tl->s.current, me, __ATOMIC_ACQUIRE);
}
/**
--
2.7.4