The refcnt update of stored mbufs in memif driver is redundant since
those mbufs are only freed in eth_memif_tx_zc(). No other place can
free those stored mbufs quietly. By removing this redundant update
single core dpdk memif performance can be improved by 7.5%.
testpmd stats on Arm Neoverse N1 (Ampere Altra)
+-----------------------------+-----------------------+
| | With refcnt update | Without refcnt update |
+--------+--------------------+-----------------------+
| Rx-pps | 2748851 | 2955487 |
+--------+--------------------+-----------------------+
| Tx-pps | 2748812 | 2955436 |
+--------+--------------------+-----------------------+
Fixes: 43b815d88188 ("net/memif: support zero-copy slave")
Cc: jgraj...@cisco.com
Signed-off-by: Liangxing Wang <liangxing.w...@arm.com>
Signed-off-by: Wathsala Vithanage <wathsala.vithan...@arm.com>
Reviewed-by: Ruifeng Wang <ruifeng.w...@arm.com>
---
.mailmap | 2 ++
drivers/net/memif/rte_eth_memif.c | 6 ------
2 files changed, 2 insertions(+), 6 deletions(-)
diff --git a/.mailmap b/.mailmap
index de339562f4..00a642fcc3 100644
--- a/.mailmap
+++ b/.mailmap
@@ -791,6 +791,7 @@ Liang Ma <lian...@bytedance.com> <lian...@liangbit.com>
<liang.j...@intel.com>
Liang-Min Larry Wang <liang-min.w...@intel.com>
Liang Xu <liang...@cinfotech.cn>
Liang Zhang <zhangli...@bigo.sg>
+Liangxing Wang <liangxing.w...@arm.com>
Li Feng <fen...@smartx.com>
Li Han <han....@zte.com.cn>
Lihong Ma <lihongx...@intel.com>
@@ -1506,6 +1507,7 @@ Vlad Zolotarov <vl...@cloudius-systems.com>
Vlastimil Kosar <ko...@rehivetech.com>
Volodymyr Fialko <vfia...@marvell.com>
Vu Pham <vuhu...@mellanox.com>
+Wathsala Vithanage <wathsala.vithan...@arm.com>
Wajeeh Atrash <atrwa...@amazon.com>
Walter Heymans <walter.heym...@corigine.com>
Wang Sheng-Hui <shh...@gmail.com>
diff --git a/drivers/net/memif/rte_eth_memif.c
b/drivers/net/memif/rte_eth_memif.c
index 7cc8c0da91..962d390b90 100644
--- a/drivers/net/memif/rte_eth_memif.c
+++ b/drivers/net/memif/rte_eth_memif.c
@@ -265,8 +265,6 @@ memif_free_stored_mbufs(struct pmd_process_private
*proc_private, struct memif_q
cur_tail = __atomic_load_n(&ring->tail, __ATOMIC_ACQUIRE);
while (mq->last_tail != cur_tail) {
RTE_MBUF_PREFETCH_TO_FREE(mq->buffers[(mq->last_tail + 1) &
mask]);
- /* Decrement refcnt and free mbuf. (current segment) */
- rte_mbuf_refcnt_update(mq->buffers[mq->last_tail & mask], -1);
rte_pktmbuf_free_seg(mq->buffers[mq->last_tail & mask]);
mq->last_tail++;
}
@@ -825,10 +823,6 @@ memif_tx_one_zc(struct pmd_process_private *proc_private,
struct memif_queue *mq
next_in_chain:
/* store pointer to mbuf to free it later */
mq->buffers[slot & mask] = mbuf;
- /* Increment refcnt to make sure the buffer is not freed before server
- * receives it. (current segment)
- */
- rte_mbuf_refcnt_update(mbuf, 1);
/* populate descriptor */
d0 = &ring->desc[slot & mask];
d0->length = rte_pktmbuf_data_len(mbuf);
--
2.25.1
