Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 2c4a2f7d authored by Toshiaki Makita's avatar Toshiaki Makita Committed by David S. Miller
Browse files

virtio_net: Make drop counter per-queue 



Since when XDP was introduced, drop counter has been able to be updated
much more frequently than before, as XDP_DROP increments the counter.
Thus for performance analysis per-queue drop counter would be useful.

Also this avoids cache contention and race on updating the counter. It
is currently racy because napi handlers read-modify-write it without any
locks.

There are more counters in dev->stats that are racy, but I left them
per-device, because they are rarely updated and does not worth being
per-queue counters IMHO. To fix them we need atomic ops or some kind of
locks.

Signed-off-by: default avatarToshiaki Makita <makita.toshiaki@lab.ntt.co.jp>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent a0929a44

drivers/net/virtio_net.c

+8 −5
Original line number Diff line number Diff line
@@ -87,6 +87,7 @@ struct virtnet_sq_stats { 
struct virtnet_rq_stat_items {

	u64 packets;

	u64 bytes;

	u64 drops;

};



struct virtnet_rq_stats {
@@ -109,6 +110,7 @@ static const struct virtnet_stat_desc virtnet_sq_stats_desc[] = { 
static const struct virtnet_stat_desc virtnet_rq_stats_desc[] = {

	{ "packets",	VIRTNET_RQ_STAT(packets) },

	{ "bytes",	VIRTNET_RQ_STAT(bytes) },

	{ "drops",	VIRTNET_RQ_STAT(drops) },

};



#define VIRTNET_SQ_STATS_LEN	ARRAY_SIZE(virtnet_sq_stats_desc)
@@ -705,7 +707,7 @@ static struct sk_buff *receive_small(struct net_device *dev, 


err_xdp:

	rcu_read_unlock();

	dev->stats.rx_dropped++;

	stats->rx.drops++;

	put_page(page);

xdp_xmit:

	return NULL;
@@ -728,7 +730,7 @@ static struct sk_buff *receive_big(struct net_device *dev, 
	return skb;



err:

	dev->stats.rx_dropped++;

	stats->rx.drops++;

	give_pages(rq, page);

	return NULL;

}
@@ -952,7 +954,7 @@ static struct sk_buff *receive_mergeable(struct net_device *dev, 
		put_page(page);

	}

err_buf:

	dev->stats.rx_dropped++;

	stats->rx.drops++;

	dev_kfree_skb(head_skb);

xdp_xmit:

	return NULL;
@@ -1632,7 +1634,7 @@ static void virtnet_stats(struct net_device *dev, 
	int i;



	for (i = 0; i < vi->max_queue_pairs; i++) {

		u64 tpackets, tbytes, rpackets, rbytes;

		u64 tpackets, tbytes, rpackets, rbytes, rdrops;

		struct receive_queue *rq = &vi->rq[i];

		struct send_queue *sq = &vi->sq[i];
@@ -1646,17 +1648,18 @@ static void virtnet_stats(struct net_device *dev, 
			start = u64_stats_fetch_begin_irq(&rq->stats.syncp);

			rpackets = rq->stats.items.packets;

			rbytes   = rq->stats.items.bytes;

			rdrops   = rq->stats.items.drops;

		} while (u64_stats_fetch_retry_irq(&rq->stats.syncp, start));



		tot->rx_packets += rpackets;

		tot->tx_packets += tpackets;

		tot->rx_bytes   += rbytes;

		tot->tx_bytes   += tbytes;

		tot->rx_dropped += rdrops;

	}



	tot->tx_dropped = dev->stats.tx_dropped;

	tot->tx_fifo_errors = dev->stats.tx_fifo_errors;

	tot->rx_dropped = dev->stats.rx_dropped;

	tot->rx_length_errors = dev->stats.rx_length_errors;

	tot->rx_frame_errors = dev->stats.rx_frame_errors;

}