From: Stephen Hemminger <stephen@networkplumber.org>
To: huawei.xie@intel.com, changchun.ouyang@intel.com
Cc: dev@dpdk.org
Subject: [dpdk-dev] [PATCH 1/5] virtio: clean up space checks on xmit
Date: Sun, 18 Oct 2015 22:16:08 -0700 [thread overview]
Message-ID: <1445231772-17467-2-git-send-email-stephen@networkplumber.org> (raw)
In-Reply-To: <1445231772-17467-1-git-send-email-stephen@networkplumber.org>
The space check for transmit ring only needs a single conditional.
I.e only need to recheck for space if there was no space in first check.
This can help performance and simplifies loop.
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
---
drivers/net/virtio/virtio_rxtx.c | 66 ++++++++++++++++------------------------
1 file changed, 27 insertions(+), 39 deletions(-)
diff --git a/drivers/net/virtio/virtio_rxtx.c b/drivers/net/virtio/virtio_rxtx.c
index c5b53bb..5b50ed0 100644
--- a/drivers/net/virtio/virtio_rxtx.c
+++ b/drivers/net/virtio/virtio_rxtx.c
@@ -745,7 +745,6 @@ uint16_t
virtio_xmit_pkts(void *tx_queue, struct rte_mbuf **tx_pkts, uint16_t nb_pkts)
{
struct virtqueue *txvq = tx_queue;
- struct rte_mbuf *txm;
uint16_t nb_used, nb_tx;
int error;
@@ -759,57 +758,46 @@ virtio_xmit_pkts(void *tx_queue, struct rte_mbuf **tx_pkts, uint16_t nb_pkts)
if (likely(nb_used > txvq->vq_nentries - txvq->vq_free_thresh))
virtio_xmit_cleanup(txvq, nb_used);
- nb_tx = 0;
+ for (nb_tx = 0; nb_tx < nb_pkts; nb_tx++) {
+ struct rte_mbuf *txm = tx_pkts[nb_tx];
+ int need = txm->nb_segs - txvq->vq_free_cnt + 1;
- while (nb_tx < nb_pkts) {
- /* Need one more descriptor for virtio header. */
- int need = tx_pkts[nb_tx]->nb_segs - txvq->vq_free_cnt + 1;
-
- /*Positive value indicates it need free vring descriptors */
+ /* Positive value indicates it need free vring descriptors */
if (unlikely(need > 0)) {
nb_used = VIRTQUEUE_NUSED(txvq);
virtio_rmb();
need = RTE_MIN(need, (int)nb_used);
virtio_xmit_cleanup(txvq, need);
- need = (int)tx_pkts[nb_tx]->nb_segs -
- txvq->vq_free_cnt + 1;
- }
-
- /*
- * Zero or negative value indicates it has enough free
- * descriptors to use for transmitting.
- */
- if (likely(need <= 0)) {
- txm = tx_pkts[nb_tx];
-
- /* Do VLAN tag insertion */
- if (unlikely(txm->ol_flags & PKT_TX_VLAN_PKT)) {
- error = rte_vlan_insert(&txm);
- if (unlikely(error)) {
- rte_pktmbuf_free(txm);
- ++nb_tx;
- continue;
- }
+ need = txm->nb_segs - txvq->vq_free_cnt + 1;
+ if (unlikely(need > 0)) {
+ PMD_TX_LOG(ERR,
+ "No free tx descriptors to transmit");
+ break;
}
+ }
- /* Enqueue Packet buffers */
- error = virtqueue_enqueue_xmit(txvq, txm);
+ /* Do VLAN tag insertion */
+ if (unlikely(txm->ol_flags & PKT_TX_VLAN_PKT)) {
+ error = rte_vlan_insert(&txm);
if (unlikely(error)) {
- if (error == ENOSPC)
- PMD_TX_LOG(ERR, "virtqueue_enqueue Free count = 0");
- else if (error == EMSGSIZE)
- PMD_TX_LOG(ERR, "virtqueue_enqueue Free count < 1");
- else
- PMD_TX_LOG(ERR, "virtqueue_enqueue error: %d", error);
- break;
+ rte_pktmbuf_free(txm);
+ continue;
}
- nb_tx++;
- txvq->bytes += txm->pkt_len;
- } else {
- PMD_TX_LOG(ERR, "No free tx descriptors to transmit");
+ }
+
+ /* Enqueue Packet buffers */
+ error = virtqueue_enqueue_xmit(txvq, txm);
+ if (unlikely(error)) {
+ if (error == ENOSPC)
+ PMD_TX_LOG(ERR, "virtqueue_enqueue Free count = 0");
+ else if (error == EMSGSIZE)
+ PMD_TX_LOG(ERR, "virtqueue_enqueue Free count < 1");
+ else
+ PMD_TX_LOG(ERR, "virtqueue_enqueue error: %d", error);
break;
}
+ txvq->bytes += txm->pkt_len;
}
txvq->packets += nb_tx;
--
2.1.4
next prev parent reply other threads:[~2015-10-19 5:16 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-10-19 5:16 [dpdk-dev] [PATCH v2 0/5] virtio: Tx performance improvements Stephen Hemminger
2015-10-19 5:16 ` Stephen Hemminger [this message]
2015-10-19 8:02 ` [dpdk-dev] [PATCH 1/5] virtio: clean up space checks on xmit Xie, Huawei
2015-10-19 15:48 ` Stephen Hemminger
2015-10-19 16:27 ` Xie, Huawei
2015-10-19 5:16 ` [dpdk-dev] [PATCH 2/5] virtio: don't use unlikely for normal tx stuff Stephen Hemminger
2015-10-19 5:16 ` [dpdk-dev] [PATCH 3/5] virtio: use indirect ring elements Stephen Hemminger
2015-10-19 13:19 ` Xie, Huawei
2015-10-19 15:47 ` Stephen Hemminger
2015-10-19 16:18 ` Xie, Huawei
2015-10-30 18:01 ` Thomas Monjalon
2015-10-19 5:16 ` [dpdk-dev] [PATCH 4/5] virtio: use any layout on transmit Stephen Hemminger
2015-10-19 16:28 ` Xie, Huawei
2015-10-19 16:43 ` Stephen Hemminger
2015-10-19 16:56 ` Xie, Huawei
2015-10-26 23:47 ` Stephen Hemminger
2015-10-19 17:19 ` Stephen Hemminger
2015-10-19 5:16 ` [dpdk-dev] [PATCH 5/5] virtio: optimize transmit enqueue Stephen Hemminger
2015-10-20 1:48 ` Xie, Huawei
2015-10-21 13:18 ` [dpdk-dev] [PATCH v2 0/5] virtio: Tx performance improvements Thomas Monjalon
2015-10-22 10:38 ` Xie, Huawei
2015-10-22 12:13 ` Xie, Huawei
2015-10-22 16:04 ` Stephen Hemminger
2015-10-23 9:00 ` Xie, Huawei
2015-10-26 23:52 ` Stephen Hemminger
2015-10-27 1:56 ` Xie, Huawei
2015-10-27 2:23 ` Stephen Hemminger
2015-10-27 2:38 ` Xie, Huawei
2015-10-26 14:05 ` Xie, Huawei
2016-01-05 8:10 ` Xie, Huawei
2016-01-06 12:03 ` Thomas Monjalon
2016-01-14 13:49 ` Xie, Huawei
2016-03-04 6:18 ` Xie, Huawei
2016-03-04 18:17 ` Stephen Hemminger
2016-03-08 1:38 ` Xie, Huawei
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