[dpdk-dev] [PATCH] mbuf: optimize first reference increment in rte_pktmbuf_attach
Olivier Matz
olivier.matz at 6wind.com
Mon Jun 1 11:32:25 CEST 2015
As it's done in __rte_pktmbuf_prefree_seg(), we can avoid using an
atomic increment in rte_pktmbuf_attach() by checking if we are the
only owner of the mbuf first.
Signed-off-by: Olivier Matz <olivier.matz at 6wind.com>
---
lib/librte_mbuf/rte_mbuf.h | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/lib/librte_mbuf/rte_mbuf.h b/lib/librte_mbuf/rte_mbuf.h
index ab6de67..cea35b7 100644
--- a/lib/librte_mbuf/rte_mbuf.h
+++ b/lib/librte_mbuf/rte_mbuf.h
@@ -838,7 +838,11 @@ static inline void rte_pktmbuf_attach(struct rte_mbuf *mi, struct rte_mbuf *m)
else
md = rte_mbuf_from_indirect(m);
- rte_mbuf_refcnt_update(md, 1);
+ /* optimize the case where we are the only owner */
+ if (likely(rte_mbuf_refcnt_read(md) == 1))
+ rte_mbuf_refcnt_set(md, 2);
+ else
+ rte_mbuf_refcnt_update(md, 1);
mi->priv_size = m->priv_size;
mi->buf_physaddr = m->buf_physaddr;
mi->buf_addr = m->buf_addr;
--
2.1.4
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