The main purpose of this patch is adding a way of checking per-queue stats.
It's useful to debug performance problems on multiqueue environment.
$ ethtool -S ens10
NIC statistics:
rx_queue_0_packets: 2090408
rx_queue_0_bytes: 3164825094
rx_queue_1_packets: 2082531
rx_queue_1_bytes: 3152932314
tx_queue_0_packets: 2770841
tx_queue_0_bytes: 4194955474
tx_queue_1_packets: 3084697
tx_queue_1_bytes: 4670196372
This change converts existing per-cpu stats structure into per-queue one.
This should not impact on performance since each queue counter is not
updated concurrently by multiple cpus.
Performance numbers:
- Guest has 2 vcpus and 2 queues
- Guest runs netserver
- Host runs 100-flow super_netperf
Before After Diff
UDP_STREAM 18byte 86.22 87.00 +0.90%
UDP_STREAM 1472byte 4055.27 4042.18 -0.32%
TCP_STREAM 16956.32 16890.63 -0.39%
UDP_RR 178667.11 185862.70 +4.03%
TCP_RR 128473.04 124985.81 -2.71%
Signed-off-by: Toshiaki Makita <makita.toshi...@lab.ntt.co.jp>
---
v2:
- Removed redundant counters which can be obtained from dev_get_stats.
- Made queue counter structure different for tx and rx so they can be
easily extended separately, as some additional counters are expected
like XDP related ones and VM-Exit event.
- Added performance numbers in commitlog.
drivers/net/virtio_net.c | 191 ++++++++++++++++++++++++++++++++++-------------
1 file changed, 141 insertions(+), 50 deletions(-)
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 12dfc5f..626c273 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -66,16 +66,39 @@
VIRTIO_NET_F_GUEST_UFO
};
-struct virtnet_stats {
- struct u64_stats_sync tx_syncp;
- struct u64_stats_sync rx_syncp;
- u64 tx_bytes;
- u64 tx_packets;
-
- u64 rx_bytes;
- u64 rx_packets;
+struct virtnet_stat_desc {
+ char desc[ETH_GSTRING_LEN];
+ size_t offset;
};
+struct virtnet_sq_stats {
+ struct u64_stats_sync syncp;
+ u64 packets;
+ u64 bytes;
+};
+
+struct virtnet_rq_stats {
+ struct u64_stats_sync syncp;
+ u64 packets;
+ u64 bytes;
+};
+
+#define VIRTNET_SQ_STAT(m) offsetof(struct virtnet_sq_stats, m)
+#define VIRTNET_RQ_STAT(m) offsetof(struct virtnet_rq_stats, m)
+
+static const struct virtnet_stat_desc virtnet_sq_stats_desc[] = {
+ { "packets", VIRTNET_SQ_STAT(packets) },
+ { "bytes", VIRTNET_SQ_STAT(bytes) },
+};
+
+static const struct virtnet_stat_desc virtnet_rq_stats_desc[] = {
+ { "packets", VIRTNET_RQ_STAT(packets) },
+ { "bytes", VIRTNET_RQ_STAT(bytes) },
+};
+
+#define VIRTNET_SQ_STATS_LEN ARRAY_SIZE(virtnet_sq_stats_desc)
+#define VIRTNET_RQ_STATS_LEN ARRAY_SIZE(virtnet_rq_stats_desc)
+
/* Internal representation of a send virtqueue */
struct send_queue {
/* Virtqueue associated with this send _queue */
@@ -87,6 +110,8 @@ struct send_queue {
/* Name of the send queue: output.$index */
char name[40];
+ struct virtnet_sq_stats stats;
+
struct napi_struct napi;
};
@@ -99,6 +124,8 @@ struct receive_queue {
struct bpf_prog __rcu *xdp_prog;
+ struct virtnet_rq_stats stats;
+
/* Chain pages by the private ptr. */
struct page *pages;
@@ -152,9 +179,6 @@ struct virtnet_info {
/* Packet virtio header size */
u8 hdr_len;
- /* Active statistics */
- struct virtnet_stats __percpu *stats;
-
/* Work struct for refilling if we run low on memory. */
struct delayed_work refill;
@@ -1127,7 +1151,6 @@ static int virtnet_receive(struct receive_queue *rq, int
budget, bool *xdp_xmit)
struct virtnet_info *vi = rq->vq->vdev->priv;
unsigned int len, received = 0, bytes = 0;
void *buf;
- struct virtnet_stats *stats = this_cpu_ptr(vi->stats);
if (!vi->big_packets || vi->mergeable_rx_bufs) {
void *ctx;
@@ -1150,10 +1173,10 @@ static int virtnet_receive(struct receive_queue *rq,
int budget, bool *xdp_xmit)
schedule_delayed_work(&vi->refill, 0);
}
- u64_stats_update_begin(&stats->rx_syncp);
- stats->rx_bytes += bytes;
- stats->rx_packets += received;
- u64_stats_update_end(&stats->rx_syncp);
+ u64_stats_update_begin(&rq->stats.syncp);
+ rq->stats.bytes += bytes;
+ rq->stats.packets += received;
+ u64_stats_update_end(&rq->stats.syncp);
return received;
}
@@ -1162,8 +1185,6 @@ static void free_old_xmit_skbs(struct send_queue *sq)
{
struct sk_buff *skb;
unsigned int len;
- struct virtnet_info *vi = sq->vq->vdev->priv;
- struct virtnet_stats *stats = this_cpu_ptr(vi->stats);
unsigned int packets = 0;
unsigned int bytes = 0;
@@ -1182,10 +1203,10 @@ static void free_old_xmit_skbs(struct send_queue *sq)
if (!packets)
return;
- u64_stats_update_begin(&stats->tx_syncp);
- stats->tx_bytes += bytes;
- stats->tx_packets += packets;
- u64_stats_update_end(&stats->tx_syncp);
+ u64_stats_update_begin(&sq->stats.syncp);
+ sq->stats.bytes += bytes;
+ sq->stats.packets += packets;
+ u64_stats_update_end(&sq->stats.syncp);
}
static void virtnet_poll_cleantx(struct receive_queue *rq)
@@ -1474,24 +1495,25 @@ static void virtnet_stats(struct net_device *dev,
struct rtnl_link_stats64 *tot)
{
struct virtnet_info *vi = netdev_priv(dev);
- int cpu;
unsigned int start;
+ int i;
- for_each_possible_cpu(cpu) {
- struct virtnet_stats *stats = per_cpu_ptr(vi->stats, cpu);
+ for (i = 0; i < vi->max_queue_pairs; i++) {
u64 tpackets, tbytes, rpackets, rbytes;
+ struct receive_queue *rq = &vi->rq[i];
+ struct send_queue *sq = &vi->sq[i];
do {
- start = u64_stats_fetch_begin_irq(&stats->tx_syncp);
- tpackets = stats->tx_packets;
- tbytes = stats->tx_bytes;
- } while (u64_stats_fetch_retry_irq(&stats->tx_syncp, start));
+ start = u64_stats_fetch_begin_irq(&sq->stats.syncp);
+ tpackets = sq->stats.packets;
+ tbytes = sq->stats.bytes;
+ } while (u64_stats_fetch_retry_irq(&sq->stats.syncp, start));
do {
- start = u64_stats_fetch_begin_irq(&stats->rx_syncp);
- rpackets = stats->rx_packets;
- rbytes = stats->rx_bytes;
- } while (u64_stats_fetch_retry_irq(&stats->rx_syncp, start));
+ start = u64_stats_fetch_begin_irq(&rq->stats.syncp);
+ rpackets = rq->stats.packets;
+ rbytes = rq->stats.bytes;
+ } while (u64_stats_fetch_retry_irq(&rq->stats.syncp, start));
tot->rx_packets += rpackets;
tot->tx_packets += tpackets;
@@ -1829,6 +1851,83 @@ static int virtnet_set_channels(struct net_device *dev,
return err;
}
+static void virtnet_get_strings(struct net_device *dev, u32 stringset, u8
*data)
+{
+ struct virtnet_info *vi = netdev_priv(dev);
+ char *p = (char *)data;
+ unsigned int i, j;
+
+ switch (stringset) {
+ case ETH_SS_STATS:
+ for (i = 0; i < vi->curr_queue_pairs; i++) {
+ for (j = 0; j < VIRTNET_RQ_STATS_LEN; j++) {
+ snprintf(p, ETH_GSTRING_LEN, "rx_queue_%u_%s",
+ i, virtnet_rq_stats_desc[j].desc);
+ p += ETH_GSTRING_LEN;
+ }
+ }
+
+ for (i = 0; i < vi->curr_queue_pairs; i++) {
+ for (j = 0; j < VIRTNET_SQ_STATS_LEN; j++) {
+ snprintf(p, ETH_GSTRING_LEN, "tx_queue_%u_%s",
+ i, virtnet_sq_stats_desc[j].desc);
+ p += ETH_GSTRING_LEN;
+ }
+ }
+ break;
+ }
+}
+
+static int virtnet_get_sset_count(struct net_device *dev, int sset)
+{
+ struct virtnet_info *vi = netdev_priv(dev);
+
+ switch (sset) {
+ case ETH_SS_STATS:
+ return vi->curr_queue_pairs * (VIRTNET_RQ_STATS_LEN +
+ VIRTNET_SQ_STATS_LEN);
+ default:
+ return -EOPNOTSUPP;
+ }
+}
+
+static void virtnet_get_ethtool_stats(struct net_device *dev,
+ struct ethtool_stats *stats, u64 *data)
+{
+ struct virtnet_info *vi = netdev_priv(dev);
+ unsigned int idx = 0, start, i, j;
+ const u8 *stats_base;
+ size_t offset;
+
+ for (i = 0; i < vi->curr_queue_pairs; i++) {
+ struct receive_queue *rq = &vi->rq[i];
+
+ stats_base = (u8 *)&rq->stats;
+ do {
+ start = u64_stats_fetch_begin_irq(&rq->stats.syncp);
+ for (j = 0; j < VIRTNET_RQ_STATS_LEN; j++) {
+ offset = virtnet_rq_stats_desc[j].offset;
+ data[idx + j] = *(u64 *)(stats_base + offset);
+ }
+ } while (u64_stats_fetch_retry_irq(&rq->stats.syncp, start));
+ idx += VIRTNET_RQ_STATS_LEN;
+ }
+
+ for (i = 0; i < vi->curr_queue_pairs; i++) {
+ struct send_queue *sq = &vi->sq[i];
+
+ stats_base = (u8 *)&sq->stats;
+ do {
+ start = u64_stats_fetch_begin_irq(&sq->stats.syncp);
+ for (j = 0; j < VIRTNET_SQ_STATS_LEN; j++) {
+ offset = virtnet_sq_stats_desc[j].offset;
+ data[idx + j] = *(u64 *)(stats_base + offset);
+ }
+ } while (u64_stats_fetch_retry_irq(&sq->stats.syncp, start));
+ idx += VIRTNET_SQ_STATS_LEN;
+ }
+}
+
static void virtnet_get_channels(struct net_device *dev,
struct ethtool_channels *channels)
{
@@ -1928,6 +2027,9 @@ static void virtnet_update_settings(struct virtnet_info
*vi)
.get_drvinfo = virtnet_get_drvinfo,
.get_link = ethtool_op_get_link,
.get_ringparam = virtnet_get_ringparam,
+ .get_strings = virtnet_get_strings,
+ .get_sset_count = virtnet_get_sset_count,
+ .get_ethtool_stats = virtnet_get_ethtool_stats,
.set_channels = virtnet_set_channels,
.get_channels = virtnet_get_channels,
.get_ts_info = ethtool_op_get_ts_info,
@@ -2420,6 +2522,9 @@ static int virtnet_alloc_queues(struct virtnet_info *vi)
sg_init_table(vi->rq[i].sg, ARRAY_SIZE(vi->rq[i].sg));
ewma_pkt_len_init(&vi->rq[i].mrg_avg_pkt_len);
sg_init_table(vi->sq[i].sg, ARRAY_SIZE(vi->sq[i].sg));
+
+ u64_stats_init(&vi->rq[i].stats.syncp);
+ u64_stats_init(&vi->sq[i].stats.syncp);
}
return 0;
@@ -2544,7 +2649,7 @@ static int virtnet_validate(struct virtio_device *vdev)
static int virtnet_probe(struct virtio_device *vdev)
{
- int i, err;
+ int i, err = -ENOMEM;
struct net_device *dev;
struct virtnet_info *vi;
u16 max_queue_pairs;
@@ -2621,17 +2726,6 @@ static int virtnet_probe(struct virtio_device *vdev)
vi->dev = dev;
vi->vdev = vdev;
vdev->priv = vi;
- vi->stats = alloc_percpu(struct virtnet_stats);
- err = -ENOMEM;
- if (vi->stats == NULL)
- goto free;
-
- for_each_possible_cpu(i) {
- struct virtnet_stats *virtnet_stats;
- virtnet_stats = per_cpu_ptr(vi->stats, i);
- u64_stats_init(&virtnet_stats->tx_syncp);
- u64_stats_init(&virtnet_stats->rx_syncp);
- }
INIT_WORK(&vi->config_work, virtnet_config_changed_work);
@@ -2668,7 +2762,7 @@ static int virtnet_probe(struct virtio_device *vdev)
*/
dev_err(&vdev->dev, "device MTU appears to have changed
"
"it is now %d < %d", mtu, dev->min_mtu);
- goto free_stats;
+ goto free;
}
dev->mtu = mtu;
@@ -2692,7 +2786,7 @@ static int virtnet_probe(struct virtio_device *vdev)
/* Allocate/initialize the rx/tx queues, and invoke find_vqs */
err = init_vqs(vi);
if (err)
- goto free_stats;
+ goto free;
#ifdef CONFIG_SYSFS
if (vi->mergeable_rx_bufs)
@@ -2747,8 +2841,6 @@ static int virtnet_probe(struct virtio_device *vdev)
cancel_delayed_work_sync(&vi->refill);
free_receive_page_frags(vi);
virtnet_del_vqs(vi);
-free_stats:
- free_percpu(vi->stats);
free:
free_netdev(dev);
return err;
@@ -2781,7 +2873,6 @@ static void virtnet_remove(struct virtio_device *vdev)
remove_vq_common(vi);
- free_percpu(vi->stats);
free_netdev(vi->dev);
}
--
1.8.3.1
