From: Heng Qi <redacted>
Sent: Tuesday, January 30, 2024 9:17 AM
在 2024/1/30 下午10:25, Daniel Jurgens 写道:

quoted

Add a tx queue stop and wake counters, they are useful for debugging.

	$ ethtool -S ens5f2 | grep 'tx_stop\|tx_wake'
	...
	tx_queue_1_tx_stop: 16726
	tx_queue_1_tx_wake: 16726
	...
	tx_queue_8_tx_stop: 1500110
	tx_queue_8_tx_wake: 1500110

Signed-off-by: Daniel Jurgens <redacted>
Reviewed-by: Parav Pandit <redacted>
---
  drivers/net/virtio_net.c | 26 ++++++++++++++++++++++++--
  1 file changed, 24 insertions(+), 2 deletions(-)

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index

3cb8aa193884..7e3c31ceaf7e 100644

--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c

@@ -88,6 +88,8 @@ struct virtnet_sq_stats {
  	u64_stats_t xdp_tx_drops;
  	u64_stats_t kicks;
  	u64_stats_t tx_timeouts;
+	u64_stats_t tx_stop;
+	u64_stats_t tx_wake;
  };

Hi Daniel!

tx_stop/wake only counts the status in the I/O path.
Do the status of virtnet_config_changed_work and virtnet_tx_resize need to
be counted?

My motivation for the counter is detecting full TX queues. I don't think counting them in the control path is useful, but it can be done if you disagree.

Thanks,
Heng

quoted

  struct virtnet_rq_stats {

@@ -112,6 +114,8 @@ static const struct virtnet_stat_desc

virtnet_sq_stats_desc[] = {

quoted

  	{ "xdp_tx_drops",	VIRTNET_SQ_STAT(xdp_tx_drops) },
  	{ "kicks",		VIRTNET_SQ_STAT(kicks) },
  	{ "tx_timeouts",	VIRTNET_SQ_STAT(tx_timeouts) },
+	{ "tx_stop",		VIRTNET_SQ_STAT(tx_stop) },
+	{ "tx_wake",		VIRTNET_SQ_STAT(tx_wake) },
  };

  static const struct virtnet_stat_desc virtnet_rq_stats_desc[] = { @@
-843,6 +847,9 @@ static void check_sq_full_and_disable(struct virtnet_info

*vi,

quoted

  	 */
  	if (sq->vq->num_free < 2+MAX_SKB_FRAGS) {
  		netif_stop_subqueue(dev, qnum);
+		u64_stats_update_begin(&sq->stats.syncp);
+		u64_stats_inc(&sq->stats.tx_stop);
+		u64_stats_update_end(&sq->stats.syncp);
  		if (use_napi) {
  			if (unlikely(!virtqueue_enable_cb_delayed(sq->vq)))
  				virtqueue_napi_schedule(&sq->napi, sq-
vq); @@ -851,6 +858,9 @@
static void check_sq_full_and_disable(struct virtnet_info *vi,
  			free_old_xmit_skbs(sq, false);
  			if (sq->vq->num_free >= 2+MAX_SKB_FRAGS) {
  				netif_start_subqueue(dev, qnum);
+				u64_stats_update_begin(&sq->stats.syncp);
+				u64_stats_inc(&sq->stats.tx_wake);
+				u64_stats_update_end(&sq->stats.syncp);
  				virtqueue_disable_cb(sq->vq);
  			}
  		}

@@ -2163,8 +2173,14 @@ static void virtnet_poll_cleantx(struct

receive_queue *rq)

quoted

  			free_old_xmit_skbs(sq, true);
  		} while (unlikely(!virtqueue_enable_cb_delayed(sq->vq)));

-		if (sq->vq->num_free >= 2 + MAX_SKB_FRAGS)
+		if (sq->vq->num_free >= 2 + MAX_SKB_FRAGS) {
+			if (netif_tx_queue_stopped(txq)) {
+				u64_stats_update_begin(&sq->stats.syncp);
+				u64_stats_inc(&sq->stats.tx_wake);
+				u64_stats_update_end(&sq->stats.syncp);
+			}
  			netif_tx_wake_queue(txq);
+		}

  		__netif_tx_unlock(txq);
  	}

@@ -2310,8 +2326,14 @@ static int virtnet_poll_tx(struct napi_struct

*napi, int budget)

quoted

  	virtqueue_disable_cb(sq->vq);
  	free_old_xmit_skbs(sq, true);

-	if (sq->vq->num_free >= 2 + MAX_SKB_FRAGS)
+	if (sq->vq->num_free >= 2 + MAX_SKB_FRAGS) {
+		if (netif_tx_queue_stopped(txq)) {
+			u64_stats_update_begin(&sq->stats.syncp);
+			u64_stats_inc(&sq->stats.tx_wake);
+			u64_stats_update_end(&sq->stats.syncp);
+		}
  		netif_tx_wake_queue(txq);
+	}

  	opaque = virtqueue_enable_cb_prepare(sq->vq);