From: "Morten Brørup" <mb@smartsharesystems.com>
To: olivier.matz@6wind.com, konstantin.ananyev@intel.com,
Honnappa.Nagarahalli@arm.com, nd@arm.com
Cc: dev@dpdk.org, "Morten Brørup" <mb@smartsharesystems.com>
Subject: [dpdk-dev] [PATCH 2/2] ring: empty optimization
Date: Tue, 19 May 2020 15:27:25 +0000 [thread overview]
Message-ID: <20200519152725.63486-3-mb@smartsharesystems.com> (raw)
In-Reply-To: <20200519152725.63486-1-mb@smartsharesystems.com>
Testing if the ring is empty is as simple as comparing the producer and
consumer pointers.
In theory, this optimization reduces the number of potential cache misses
from 3 to 2 by not having to read r->mask in rte_ring_count().
The modification of this function were also discussed in the RFC here:
https://mails.dpdk.org/archives/dev/2020-April/165752.html
Signed-off-by: Morten Brørup <mb@smartsharesystems.com>
---
lib/librte_ring/rte_ring.h | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/lib/librte_ring/rte_ring.h b/lib/librte_ring/rte_ring.h
index 9078e7c24..f67141482 100644
--- a/lib/librte_ring/rte_ring.h
+++ b/lib/librte_ring/rte_ring.h
@@ -733,7 +733,9 @@ rte_ring_full(const struct rte_ring *r)
static inline int
rte_ring_empty(const struct rte_ring *r)
{
- return rte_ring_count(r) == 0;
+ uint32_t prod_tail = r->prod.tail;
+ uint32_t cons_tail = r->cons.tail;
+ return cons_tail == prod_tail;
}
/**
--
2.17.1
next prev parent reply other threads:[~2020-05-19 15:27 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-13 15:31 [dpdk-dev] [PATCH] ring: empty and count optimizations Morten Brørup
2020-05-13 15:35 ` Morten Brørup
2020-05-13 17:08 ` Morten Brørup
2020-05-14 12:23 ` Ananyev, Konstantin
2020-05-14 13:45 ` Morten Brørup
2020-05-14 16:46 ` Ananyev, Konstantin
2020-05-14 18:00 ` Morten Brørup
2020-05-19 15:27 ` [dpdk-dev] [PATCH 0/2] ring: empty optimization Morten Brørup
2020-05-19 15:27 ` [dpdk-dev] [PATCH 1/2] ring: coding style cleanup Morten Brørup
2020-05-22 12:34 ` Ananyev, Konstantin
2020-05-19 15:27 ` Morten Brørup [this message]
2020-05-19 15:52 ` [dpdk-dev] [PATCH 2/2] ring: empty optimization Stephen Hemminger
2020-05-19 16:02 ` Morten Brørup
2020-07-01 9:19 ` David Marchand
2020-05-22 12:32 ` Ananyev, Konstantin
2020-07-01 9:20 ` [dpdk-dev] [PATCH 0/2] " David Marchand
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