From: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
To: "dev@dpdk.org" <dev@dpdk.org>
Cc: Hayato Momma <h-momma@ce.jp.nec.com>
Subject: [dpdk-dev] [memnic PATCH] pmd: use rte_atomic32_cmpset instead of cmpxchg
Date: Thu, 3 Apr 2014 07:34:56 +0000 [thread overview]
Message-ID: <7F861DC0615E0C47A872E6F3C5FCDDBD0109D67F@BPXM14GP.gisp.nec.co.jp> (raw)
From: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
Because DPDK has its own compare and set function to optimize to
dedicated processor type, use that rte_atomic32_cmpset() instead of
cmpxchg macro which is specially introduced for MEMNIC.
Signed-off-by: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
---
common/memnic.h | 12 ------------
pmd/pmd_memnic.c | 10 ++++++----
2 files changed, 6 insertions(+), 16 deletions(-)
diff --git a/common/memnic.h b/common/memnic.h
index 2187ac1..84e941c 100644
--- a/common/memnic.h
+++ b/common/memnic.h
@@ -120,18 +120,6 @@ struct memnic_area {
/* for userspace */
#define ACCESS_ONCE(x) (*(volatile typeof(x) *)&(x))
-static inline uint32_t cmpxchg(uint32_t *dst, uint32_t old, uint32_t new)
-{
- volatile uint32_t *ptr = (volatile uint32_t *)dst;
- uint32_t ret;
-
- asm volatile("lock; cmpxchgl %2, %1"
- : "=a" (ret), "+m" (*ptr)
- : "r" (new), "0" (old)
- : "memory");
-
- return ret;
-}
#endif /* __KERNEL__ */
#endif /* MEMNIC_H */
diff --git a/pmd/pmd_memnic.c b/pmd/pmd_memnic.c
index 4a1c1e4..4abdf26 100644
--- a/pmd/pmd_memnic.c
+++ b/pmd/pmd_memnic.c
@@ -314,7 +314,7 @@ static uint16_t memnic_xmit_pkts(void *tx_queue,
struct memnic_data *data = &adapter->nic->down;
struct memnic_packet *p;
uint16_t nr;
- int idx, old;
+ int idx;
struct rte_eth_stats *st = &adapter->stats[rte_lcore_id()];
uint64_t pkts, bytes, errs;
@@ -335,10 +335,12 @@ static uint16_t memnic_xmit_pkts(void *tx_queue,
retry:
idx = ACCESS_ONCE(adapter->down_idx);
p = &data->packets[idx];
- old = cmpxchg(&p->status, MEMNIC_PKT_ST_FREE, MEMNIC_PKT_ST_USED);
- if (old != MEMNIC_PKT_ST_FREE) {
- if (old == MEMNIC_PKT_ST_FILLED &&
+ if (unlikely(rte_atomic32_cmpset(&p->status,
+ MEMNIC_PKT_ST_FREE, MEMNIC_PKT_ST_USED) == 0)) {
+ /* cmpxchg failed */
+ if (p->status == MEMNIC_PKT_ST_FILLED &&
idx == ACCESS_ONCE(adapter->down_idx)) {
+ /* what we're seeing is FILLED means queue full */
errs++;
break;
}
--
1.8.4
next reply other threads:[~2014-04-03 7:35 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-04-03 7:34 Hiroshi Shimamoto [this message]
2014-04-11 9:37 ` Olivier MATZ
2014-04-11 15:45 ` Thomas Monjalon
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