From: Jiri Pirko <j...@nvidia.com>
Add support for Byte Queue Limits (BQL).
Tested on qemu emulated virtio_net device with 1, 2 and 4 queues.
Tested with fq_codel and pfifo_fast. Super netperf with 50 threads is
running in background. Netperf TCP_RR results:
NOBQL FQC 1q: 159.56 159.33 158.50 154.31 agv: 157.925
NOBQL FQC 2q: 184.64 184.96 174.73 174.15 agv: 179.62
NOBQL FQC 4q: 994.46 441.96 416.50 499.56 agv: 588.12
NOBQL PFF 1q: 148.68 148.92 145.95 149.48 agv: 148.2575
NOBQL PFF 2q: 171.86 171.20 170.42 169.42 agv: 170.725
NOBQL PFF 4q: 1505.23 1137.23 2488.70 3507.99 agv: 2159.7875
BQL FQC 1q: 1332.80 1297.97 1351.41 1147.57 agv: 1282.4375
BQL FQC 2q: 768.30 817.72 864.43 974.40 agv: 856.2125
BQL FQC 4q: 945.66 942.68 878.51 822.82 agv: 897.4175
BQL PFF 1q: 149.69 151.49 149.40 147.47 agv: 149.5125
BQL PFF 2q: 2059.32 798.74 1844.12 381.80 agv: 1270.995
BQL PFF 4q: 1871.98 4420.02 4916.59 13268.16 agv: 6119.1875
Signed-off-by: Jiri Pirko <j...@nvidia.com>
---
v1->v2:
- moved netdev_tx_completed_queue() call into __free_old_xmit(),
propagate use_napi flag to __free_old_xmit() and only call
netdev_tx_completed_queue() in case it is true
- added forgotten call to netdev_tx_reset_queue()
- fixed stats for xdp packets
- fixed bql accounting when __free_old_xmit() is called from xdp path
- handle the !use_napi case in start_xmit() kick section
---
drivers/net/virtio_net.c | 50 +++++++++++++++++++++++++---------------
1 file changed, 32 insertions(+), 18 deletions(-)
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 61a57d134544..5863c663ccab 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -84,7 +84,9 @@ struct virtnet_stat_desc {
struct virtnet_sq_free_stats {
u64 packets;
+ u64 xdp_packets;
u64 bytes;
+ u64 xdp_bytes;
};
struct virtnet_sq_stats {
@@ -506,29 +508,33 @@ static struct xdp_frame *ptr_to_xdp(void *ptr)
return (struct xdp_frame *)((unsigned long)ptr & ~VIRTIO_XDP_FLAG);
}
-static void __free_old_xmit(struct send_queue *sq, bool in_napi,
+static void __free_old_xmit(struct send_queue *sq, struct netdev_queue *txq,
+ bool in_napi, bool use_napi,
struct virtnet_sq_free_stats *stats)
{
unsigned int len;
void *ptr;
while ((ptr = virtqueue_get_buf(sq->vq, &len)) != NULL) {
- ++stats->packets;
-
if (!is_xdp_frame(ptr)) {
struct sk_buff *skb = ptr;
pr_debug("Sent skb %p\n", skb);
+ stats->packets++;
stats->bytes += skb->len;
napi_consume_skb(skb, in_napi);
} else {
struct xdp_frame *frame = ptr_to_xdp(ptr);
- stats->bytes += xdp_get_frame_len(frame);
+ stats->xdp_packets++;
+ stats->xdp_bytes += xdp_get_frame_len(frame);
xdp_return_frame(frame);
}
}
+ if (use_napi)
+ netdev_tx_completed_queue(txq, stats->packets, stats->bytes);
+
}
/* Converting between virtqueue no. and kernel tx/rx queue no.
@@ -955,21 +961,22 @@ static void virtnet_rq_unmap_free_buf(struct virtqueue
*vq, void *buf)
virtnet_rq_free_buf(vi, rq, buf);
}
-static void free_old_xmit(struct send_queue *sq, bool in_napi)
+static void free_old_xmit(struct send_queue *sq, struct netdev_queue *txq,
+ bool in_napi, bool use_napi)
{
struct virtnet_sq_free_stats stats = {0};
- __free_old_xmit(sq, in_napi, &stats);
+ __free_old_xmit(sq, txq, in_napi, use_napi, &stats);
/* Avoid overhead when no packets have been processed
* happens when called speculatively from start_xmit.
*/
- if (!stats.packets)
+ if (!stats.packets && !stats.xdp_packets)
return;
u64_stats_update_begin(&sq->stats.syncp);
- u64_stats_add(&sq->stats.bytes, stats.bytes);
- u64_stats_add(&sq->stats.packets, stats.packets);
+ u64_stats_add(&sq->stats.bytes, stats.bytes + stats.xdp_bytes);
+ u64_stats_add(&sq->stats.packets, stats.packets + stats.xdp_packets);
u64_stats_update_end(&sq->stats.syncp);
}
@@ -1003,7 +1010,9 @@ static void check_sq_full_and_disable(struct virtnet_info
*vi,
* early means 16 slots are typically wasted.
*/
if (sq->vq->num_free < 2+MAX_SKB_FRAGS) {
- netif_stop_subqueue(dev, qnum);
+ struct netdev_queue *txq = netdev_get_tx_queue(dev, qnum);
+
+ netif_tx_stop_queue(txq);
u64_stats_update_begin(&sq->stats.syncp);
u64_stats_inc(&sq->stats.stop);
u64_stats_update_end(&sq->stats.syncp);
@@ -1012,7 +1021,7 @@ static void check_sq_full_and_disable(struct virtnet_info
*vi,
virtqueue_napi_schedule(&sq->napi, sq->vq);
} else if (unlikely(!virtqueue_enable_cb_delayed(sq->vq))) {
/* More just got used, free them then recheck. */
- free_old_xmit(sq, false);
+ free_old_xmit(sq, txq, false, use_napi);
if (sq->vq->num_free >= 2+MAX_SKB_FRAGS) {
netif_start_subqueue(dev, qnum);
u64_stats_update_begin(&sq->stats.syncp);
@@ -1138,7 +1147,8 @@ static int virtnet_xdp_xmit(struct net_device *dev,
}
/* Free up any pending old buffers before queueing new ones. */
- __free_old_xmit(sq, false, &stats);
+ __free_old_xmit(sq, netdev_get_tx_queue(dev, sq - vi->sq),
+ false, sq->napi.weight, &stats);
for (i = 0; i < n; i++) {
struct xdp_frame *xdpf = frames[i];
@@ -2313,7 +2323,7 @@ static void virtnet_poll_cleantx(struct receive_queue *rq)
do {
virtqueue_disable_cb(sq->vq);
- free_old_xmit(sq, true);
+ free_old_xmit(sq, txq, true, true);
} while (unlikely(!virtqueue_enable_cb_delayed(sq->vq)));
if (sq->vq->num_free >= 2 + MAX_SKB_FRAGS) {
@@ -2412,6 +2422,7 @@ static int virtnet_enable_queue_pair(struct virtnet_info
*vi, int qp_index)
goto err_xdp_reg_mem_model;
virtnet_napi_enable(vi->rq[qp_index].vq, &vi->rq[qp_index].napi);
+ netdev_tx_reset_queue(netdev_get_tx_queue(vi->dev, qp_index));
virtnet_napi_tx_enable(vi, vi->sq[qp_index].vq, &vi->sq[qp_index].napi);
return 0;
@@ -2471,7 +2482,7 @@ static int virtnet_poll_tx(struct napi_struct *napi, int
budget)
txq = netdev_get_tx_queue(vi->dev, index);
__netif_tx_lock(txq, raw_smp_processor_id());
virtqueue_disable_cb(sq->vq);
- free_old_xmit(sq, true);
+ free_old_xmit(sq, txq, true, true);
if (sq->vq->num_free >= 2 + MAX_SKB_FRAGS) {
if (netif_tx_queue_stopped(txq)) {
@@ -2559,17 +2570,18 @@ static netdev_tx_t start_xmit(struct sk_buff *skb,
struct net_device *dev)
struct send_queue *sq = &vi->sq[qnum];
int err;
struct netdev_queue *txq = netdev_get_tx_queue(dev, qnum);
- bool kick = !netdev_xmit_more();
+ bool xmit_more = netdev_xmit_more();
bool use_napi = sq->napi.weight;
+ bool kick;
/* Free up any pending old buffers before queueing new ones. */
do {
if (use_napi)
virtqueue_disable_cb(sq->vq);
- free_old_xmit(sq, false);
+ free_old_xmit(sq, txq, false, use_napi);
- } while (use_napi && kick &&
+ } while (use_napi && !xmit_more &&
unlikely(!virtqueue_enable_cb_delayed(sq->vq)));
/* timestamp packet in software */
@@ -2598,7 +2610,9 @@ static netdev_tx_t start_xmit(struct sk_buff *skb, struct
net_device *dev)
check_sq_full_and_disable(vi, dev, sq);
- if (kick || netif_xmit_stopped(txq)) {
+ kick = use_napi ? __netdev_tx_sent_queue(txq, skb->len, xmit_more) :
+ !xmit_more && netif_xmit_stopped(txq);
+ if (kick) {
if (virtqueue_kick_prepare(sq->vq) && virtqueue_notify(sq->vq))
{
u64_stats_update_begin(&sq->stats.syncp);
u64_stats_inc(&sq->stats.kicks);
--
2.45.1
