From: Long Li <lon...@microsoft.com>
Instead of allocating mbufs one by one during RX, use
rte_pktmbuf_alloc_bulk() to allocate them in a batch.
With this patch, there are no measurable performance improvements in
benchmarks. However, this patch should improve CPU cycles and reduce
potential locking conflicts in real-world applications.
Signed-off-by: Long Li <lon...@microsoft.com>
---
Change in v2:
use rte_calloc_socket() in place of rte_calloc()
v3:
add more comment explaining the benefit of doing alloc_bulk.
free mbufs that are failed to post
v4:
replace rte_calloc_socket() with a fixed array on the stack
drivers/net/mana/rx.c | 76 ++++++++++++++++++++++++++++---------------
1 file changed, 50 insertions(+), 26 deletions(-)
diff --git a/drivers/net/mana/rx.c b/drivers/net/mana/rx.c
index acad5e26cd..4fc0f789d8 100644
--- a/drivers/net/mana/rx.c
+++ b/drivers/net/mana/rx.c
@@ -59,9 +59,8 @@ mana_rq_ring_doorbell(struct mana_rxq *rxq)
}
static int
-mana_alloc_and_post_rx_wqe(struct mana_rxq *rxq)
+mana_post_rx_wqe(struct mana_rxq *rxq, struct rte_mbuf *mbuf)
{
- struct rte_mbuf *mbuf = NULL;
struct gdma_sgl_element sgl[1];
struct gdma_work_request request;
uint32_t wqe_size_in_bu;
@@ -69,12 +68,6 @@ mana_alloc_and_post_rx_wqe(struct mana_rxq *rxq)
int ret;
struct mana_mr_cache *mr;
- mbuf = rte_pktmbuf_alloc(rxq->mp);
- if (!mbuf) {
- rxq->stats.nombuf++;
- return -ENOMEM;
- }
-
mr = mana_alloc_pmd_mr(&rxq->mr_btree, priv, mbuf);
if (!mr) {
DP_LOG(ERR, "failed to register RX MR");
@@ -120,20 +113,33 @@ mana_alloc_and_post_rx_wqe(struct mana_rxq *rxq)
/*
* Post work requests for a Rx queue.
*/
+#define MANA_MBUF_BULK 32u
static int
-mana_alloc_and_post_rx_wqes(struct mana_rxq *rxq)
+mana_alloc_and_post_rx_wqes(struct mana_rxq *rxq, uint32_t count)
{
int ret;
- uint32_t i;
+ uint32_t i, batch_count;
+ struct rte_mbuf *mbufs[MANA_MBUF_BULK];
+
+more_mbufs:
+ batch_count = RTE_MIN(count, MANA_MBUF_BULK);
+ ret = rte_pktmbuf_alloc_bulk(rxq->mp, mbufs, batch_count);
+ if (ret) {
+ DP_LOG(ERR, "failed to allocate mbufs for RX");
+ rxq->stats.nombuf += count;
+
+ /* Bail out to ring doorbell for posted packets */
+ goto out;
+ }
#ifdef RTE_ARCH_32
rxq->wqe_cnt_to_short_db = 0;
#endif
- for (i = 0; i < rxq->num_desc; i++) {
- ret = mana_alloc_and_post_rx_wqe(rxq);
+ for (i = 0; i < batch_count; i++) {
+ ret = mana_post_rx_wqe(rxq, mbufs[i]);
if (ret) {
DP_LOG(ERR, "failed to post RX ret = %d", ret);
- return ret;
+ break;
}
#ifdef RTE_ARCH_32
@@ -144,8 +150,15 @@ mana_alloc_and_post_rx_wqes(struct mana_rxq *rxq)
#endif
}
- mana_rq_ring_doorbell(rxq);
+ /* Free the remaining mbufs that are not posted */
+ rte_pktmbuf_free_bulk(&mbufs[i], batch_count - i);
+
+ count -= batch_count;
+ if (count > 0)
+ goto more_mbufs;
+out:
+ mana_rq_ring_doorbell(rxq);
return ret;
}
@@ -404,7 +417,9 @@ mana_start_rx_queues(struct rte_eth_dev *dev)
}
for (i = 0; i < priv->num_queues; i++) {
- ret = mana_alloc_and_post_rx_wqes(dev->data->rx_queues[i]);
+ struct mana_rxq *rxq = dev->data->rx_queues[i];
+
+ ret = mana_alloc_and_post_rx_wqes(rxq, rxq->num_desc);
if (ret)
goto fail;
}
@@ -423,7 +438,7 @@ uint16_t
mana_rx_burst(void *dpdk_rxq, struct rte_mbuf **pkts, uint16_t pkts_n)
{
uint16_t pkt_received = 0;
- uint16_t wqe_posted = 0;
+ uint16_t wqe_consumed = 0;
struct mana_rxq *rxq = dpdk_rxq;
struct mana_priv *priv = rxq->priv;
struct rte_mbuf *mbuf;
@@ -535,18 +550,23 @@ mana_rx_burst(void *dpdk_rxq, struct rte_mbuf **pkts,
uint16_t pkts_n)
rxq->gdma_rq.tail += desc->wqe_size_in_bu;
- /* Consume this request and post another request */
- ret = mana_alloc_and_post_rx_wqe(rxq);
- if (ret) {
- DP_LOG(ERR, "failed to post rx wqe ret=%d", ret);
- break;
- }
-
- wqe_posted++;
+ /* Record the number of the RX WQE we need to post to replenish
+ * consumed RX requests
+ */
+ wqe_consumed++;
if (pkt_received == pkts_n)
break;
#ifdef RTE_ARCH_32
+ /* Always post WQE as soon as it's consumed for short DB */
+ ret = mana_alloc_and_post_rx_wqes(rxq, wqe_consumed);
+ if (ret) {
+ DRV_LOG(ERR, "failed to post %d WQEs, ret %d",
+ wqe_consumed, ret);
+ return pkt_received;
+ }
+ wqe_consumed = 0;
+
/* Ring short doorbell if approaching the wqe increment
* limit.
*/
@@ -569,8 +589,12 @@ mana_rx_burst(void *dpdk_rxq, struct rte_mbuf **pkts,
uint16_t pkts_n)
goto repoll;
}
- if (wqe_posted)
- mana_rq_ring_doorbell(rxq);
+ if (wqe_consumed) {
+ ret = mana_alloc_and_post_rx_wqes(rxq, wqe_consumed);
+ if (ret)
+ DRV_LOG(ERR, "failed to post %d WQEs, ret %d",
+ wqe_consumed, ret);
+ }
return pkt_received;
}
--
2.17.1
