From: "Hanoch Haim (hhaim)" <hhaim@cisco.com>
To: Olivier Matz <olivier.matz@6wind.com>, "dev@dpdk.org" <dev@dpdk.org>
Cc: "matvejchikov@gmail.com" <matvejchikov@gmail.com>,
"konstantin.ananyev@intel.com" <konstantin.ananyev@intel.com>
Subject: Re: [dpdk-dev] [PATCH v4] mbuf: fix mbuf free performance with non atomic refcnt
Date: Sun, 10 Dec 2017 08:37:22 +0000 [thread overview]
Message-ID: <39032469f9204aa9b707d49670ceebba@XCH-RTP-017.cisco.com> (raw)
In-Reply-To: <20171208154651.16546-1-olivier.matz@6wind.com>
Oliver, Looks great.
Thanks,
Hanoh
-----Original Message-----
From: Olivier Matz [mailto:olivier.matz@6wind.com]
Sent: Friday, December 08, 2017 5:47 PM
To: dev@dpdk.org; Hanoch Haim (hhaim)
Cc: matvejchikov@gmail.com; konstantin.ananyev@intel.com
Subject: [PATCH v4] mbuf: fix mbuf free performance with non atomic refcnt
When RTE_MBUF_REFCNT_ATOMIC=n, the decrement of the mbuf reference counter uses an atomic operation. This is not necessary and impacts the performance (seen with TRex traffic generator).
We cannot replace rte_atomic16_add_return() by rte_mbuf_refcnt_update() because it would add an additional check.
Solves this by introducing __rte_mbuf_refcnt_update(), which updates the reference counter without doing anything else.
Fixes: 8f094a9ac5d7 ("mbuf: set mbuf fields while in pool")
Suggested-by: Hanoch Haim <hhaim@cisco.com>
Signed-off-by: Olivier Matz <olivier.matz@6wind.com>
---
Hanoh,
The following patch implements what was discussed in the thread.
Are you ok with it?
Thanks,
Olivier
lib/librte_mbuf/rte_mbuf.h | 23 ++++++++++++++++++-----
1 file changed, 18 insertions(+), 5 deletions(-)
diff --git a/lib/librte_mbuf/rte_mbuf.h b/lib/librte_mbuf/rte_mbuf.h index ce8a05ddf..dd08cb72b 100644
--- a/lib/librte_mbuf/rte_mbuf.h
+++ b/lib/librte_mbuf/rte_mbuf.h
@@ -764,6 +764,13 @@ rte_mbuf_refcnt_set(struct rte_mbuf *m, uint16_t new_value)
rte_atomic16_set(&m->refcnt_atomic, new_value); }
+/* internal */
+static inline uint16_t
+__rte_mbuf_refcnt_update(struct rte_mbuf *m, int16_t value) {
+ return (uint16_t)(rte_atomic16_add_return(&m->refcnt_atomic, value));
+}
+
/**
* Adds given value to an mbuf's refcnt and returns its new value.
* @param m
@@ -788,19 +795,26 @@ rte_mbuf_refcnt_update(struct rte_mbuf *m, int16_t value)
return 1 + value;
}
- return (uint16_t)(rte_atomic16_add_return(&m->refcnt_atomic, value));
+ return __rte_mbuf_refcnt_update(m, value);
}
#else /* ! RTE_MBUF_REFCNT_ATOMIC */
+/* internal */
+static inline uint16_t
+__rte_mbuf_refcnt_update(struct rte_mbuf *m, int16_t value) {
+ m->refcnt = (uint16_t)(m->refcnt + value);
+ return m->refcnt;
+}
+
/**
* Adds given value to an mbuf's refcnt and returns its new value.
*/
static inline uint16_t
rte_mbuf_refcnt_update(struct rte_mbuf *m, int16_t value) {
- m->refcnt = (uint16_t)(m->refcnt + value);
- return m->refcnt;
+ return __rte_mbuf_refcnt_update(m, value);
}
/**
@@ -1364,8 +1378,7 @@ rte_pktmbuf_prefree_seg(struct rte_mbuf *m)
return m;
- } else if (rte_atomic16_add_return(&m->refcnt_atomic, -1) == 0) {
-
+ } else if (__rte_mbuf_refcnt_update(m, -1) == 0) {
if (RTE_MBUF_INDIRECT(m))
rte_pktmbuf_detach(m);
--
2.11.0
next prev parent reply other threads:[~2017-12-10 8:37 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-11-15 9:14 [dpdk-dev] [PATCH v3] mbuf: cleanup rte_pktmbuf_lastseg(), fix atomic usage Hanoh Haim
2017-11-15 11:13 ` Ilya Matveychikov
2017-11-15 12:46 ` Hanoch Haim (hhaim)
2017-11-15 17:30 ` Olivier MATZ
2017-11-16 7:16 ` Hanoch Haim (hhaim)
2017-11-16 8:07 ` Ilya Matveychikov
2017-11-16 8:42 ` Olivier MATZ
2017-11-16 9:06 ` Hanoch Haim (hhaim)
2017-11-16 9:32 ` Ilya Matveychikov
2017-11-16 9:37 ` Olivier MATZ
2017-11-16 9:44 ` Ilya Matveychikov
2017-11-16 10:54 ` Ananyev, Konstantin
2017-12-08 15:46 ` [dpdk-dev] [PATCH v4] mbuf: fix mbuf free performance with non atomic refcnt Olivier Matz
2017-12-08 16:04 ` Ilya Matveychikov
2017-12-08 16:19 ` Olivier MATZ
2017-12-08 16:37 ` Stephen Hemminger
2017-12-10 8:37 ` Hanoch Haim (hhaim) [this message]
2017-12-11 10:28 ` Olivier MATZ
2018-01-18 23:23 ` Thomas Monjalon
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