Jason Wang
2012-Jun-06 07:52 UTC
[V2 RFC net-next PATCH 1/2] virtio_net: convert the statistics into array
Currently, we store the statistics in the independent fields of virtnet_stats,
this is not scalable when we want to add more counters. As suggested by Michael,
this patch convert it to an array and use the enum as the index to access them.
Signed-off-by: Jason Wang <jasowang at redhat.com>
---
drivers/net/virtio_net.c | 30 +++++++++++++++++-------------
1 files changed, 17 insertions(+), 13 deletions(-)
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 5214b1e..6e4aa6f 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -41,13 +41,17 @@ module_param(gso, bool, 0444);
#define VIRTNET_SEND_COMMAND_SG_MAX 2
#define VIRTNET_DRIVER_VERSION "1.0.0"
+enum virtnet_stats_type {
+ VIRTNET_TX_BYTES,
+ VIRTNET_TX_PACKETS,
+ VIRTNET_RX_BYTES,
+ VIRTNET_RX_PACKETS,
+ VIRTNET_NUM_STATS,
+};
+
struct virtnet_stats {
struct u64_stats_sync syncp;
- u64 tx_bytes;
- u64 tx_packets;
-
- u64 rx_bytes;
- u64 rx_packets;
+ u64 data[VIRTNET_NUM_STATS];
};
struct virtnet_info {
@@ -301,8 +305,8 @@ static void receive_buf(struct net_device *dev, void *buf,
unsigned int len)
hdr = skb_vnet_hdr(skb);
u64_stats_update_begin(&stats->syncp);
- stats->rx_bytes += skb->len;
- stats->rx_packets++;
+ stats->data[VIRTNET_RX_BYTES] += skb->len;
+ stats->data[VIRTNET_RX_PACKETS]++;
u64_stats_update_end(&stats->syncp);
if (hdr->hdr.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
@@ -566,8 +570,8 @@ static unsigned int free_old_xmit_skbs(struct virtnet_info
*vi)
pr_debug("Sent skb %p\n", skb);
u64_stats_update_begin(&stats->syncp);
- stats->tx_bytes += skb->len;
- stats->tx_packets++;
+ stats->data[VIRTNET_TX_BYTES] += skb->len;
+ stats->data[VIRTNET_TX_PACKETS]++;
u64_stats_update_end(&stats->syncp);
tot_sgs += skb_vnet_hdr(skb)->num_sg;
@@ -704,10 +708,10 @@ static struct rtnl_link_stats64 *virtnet_stats(struct
net_device *dev,
do {
start = u64_stats_fetch_begin(&stats->syncp);
- tpackets = stats->tx_packets;
- tbytes = stats->tx_bytes;
- rpackets = stats->rx_packets;
- rbytes = stats->rx_bytes;
+ tpackets = stats->data[VIRTNET_TX_PACKETS];
+ tbytes = stats->data[VIRTNET_TX_BYTES];
+ rpackets = stats->data[VIRTNET_RX_PACKETS];
+ rbytes = stats->data[VIRTNET_RX_BYTES];
} while (u64_stats_fetch_retry(&stats->syncp, start));
tot->rx_packets += rpackets;
Jason Wang
2012-Jun-06 07:52 UTC
[V2 RFC net-next PATCH 2/2] virtio_net: export more statistics through ethtool
Satistics counters is useful for debugging and performance optimization, so this
patch lets virtio_net driver collect following and export them to userspace
through "ethtool -S":
- number of packets sent/received
- number of bytes sent/received
- number of callbacks for tx/rx
- number of kick for tx/rx
- number of bytes/packets queued for tx
As virtnet_stats were per-cpu, so both per-cpu and gloabl satistics were
collected like:
NIC statistics:
tx_bytes[0]: 1731209929
tx_packets[0]: 60685
tx_kicks[0]: 63
tx_callbacks[0]: 73
tx_queued_bytes[0]: 1935749360
tx_queued_packets[0]: 80652
rx_bytes[0]: 2695648
rx_packets[0]: 40767
rx_kicks[0]: 1
rx_callbacks[0]: 2077
tx_bytes[1]: 9105588697
tx_packets[1]: 344150
tx_kicks[1]: 162
tx_callbacks[1]: 905
tx_queued_bytes[1]: 8901049412
tx_queued_packets[1]: 324184
rx_bytes[1]: 23679828
rx_packets[1]: 358770
rx_kicks[1]: 6
rx_callbacks[1]: 17717
tx_bytes: 10836798626
tx_packets: 404835
tx_kicks: 225
tx_callbacks: 978
tx_queued_bytes: 10836798772
tx_queued_packets: 404836
rx_bytes: 26375476
rx_packets: 399537
rx_kicks: 7
rx_callbacks: 19794
TODO:
- more statistics
- calculate the pending bytes/pkts
Signed-off-by: Jason Wang <jasowang at redhat.com>
---
Changes from v1:
- style & typo fixs
- convert the statistics fields to array
- use unlikely()
---
drivers/net/virtio_net.c | 115 +++++++++++++++++++++++++++++++++++++++++++++-
1 files changed, 113 insertions(+), 2 deletions(-)
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 6e4aa6f..909a0a7 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -44,8 +44,14 @@ module_param(gso, bool, 0444);
enum virtnet_stats_type {
VIRTNET_TX_BYTES,
VIRTNET_TX_PACKETS,
+ VIRTNET_TX_KICKS,
+ VIRTNET_TX_CBS,
+ VIRTNET_TX_Q_BYTES,
+ VIRTNET_TX_Q_PACKETS,
VIRTNET_RX_BYTES,
VIRTNET_RX_PACKETS,
+ VIRTNET_RX_KICKS,
+ VIRTNET_RX_CBS,
VIRTNET_NUM_STATS,
};
@@ -54,6 +60,21 @@ struct virtnet_stats {
u64 data[VIRTNET_NUM_STATS];
};
+static struct {
+ char string[ETH_GSTRING_LEN];
+} virtnet_stats_str_attr[] = {
+ { "tx_bytes" },
+ { "tx_packets" },
+ { "tx_kicks" },
+ { "tx_callbacks" },
+ { "tx_queued_bytes" },
+ { "tx_queued_packets" },
+ { "rx_bytes" },
+ { "rx_packets" },
+ { "rx_kicks" },
+ { "rx_callbacks" },
+};
+
struct virtnet_info {
struct virtio_device *vdev;
struct virtqueue *rvq, *svq, *cvq;
@@ -146,6 +167,11 @@ static struct page *get_a_page(struct virtnet_info *vi,
gfp_t gfp_mask)
static void skb_xmit_done(struct virtqueue *svq)
{
struct virtnet_info *vi = svq->vdev->priv;
+ struct virtnet_stats *stats = this_cpu_ptr(vi->stats);
+
+ u64_stats_update_begin(&stats->syncp);
+ stats->data[VIRTNET_TX_CBS]++;
+ u64_stats_update_end(&stats->syncp);
/* Suppress further interrupts. */
virtqueue_disable_cb(svq);
@@ -465,6 +491,7 @@ static bool try_fill_recv(struct virtnet_info *vi, gfp_t
gfp)
{
int err;
bool oom;
+ struct virtnet_stats *stats = this_cpu_ptr(vi->stats);
do {
if (vi->mergeable_rx_bufs)
@@ -481,13 +508,24 @@ static bool try_fill_recv(struct virtnet_info *vi, gfp_t
gfp)
} while (err > 0);
if (unlikely(vi->num > vi->max))
vi->max = vi->num;
- virtqueue_kick(vi->rvq);
+ if (virtqueue_kick_prepare(vi->rvq)) {
+ virtqueue_notify(vi->rvq);
+ u64_stats_update_begin(&stats->syncp);
+ stats->data[VIRTNET_RX_KICKS]++;
+ u64_stats_update_end(&stats->syncp);
+ }
return !oom;
}
static void skb_recv_done(struct virtqueue *rvq)
{
struct virtnet_info *vi = rvq->vdev->priv;
+ struct virtnet_stats *stats = this_cpu_ptr(vi->stats);
+
+ u64_stats_update_begin(&stats->syncp);
+ stats->data[VIRTNET_RX_CBS]++;
+ u64_stats_update_end(&stats->syncp);
+
/* Schedule NAPI, Suppress further interrupts if successful. */
if (napi_schedule_prep(&vi->napi)) {
virtqueue_disable_cb(rvq);
@@ -630,7 +668,9 @@ static int xmit_skb(struct virtnet_info *vi, struct sk_buff
*skb)
static netdev_tx_t start_xmit(struct sk_buff *skb, struct net_device *dev)
{
struct virtnet_info *vi = netdev_priv(dev);
+ struct virtnet_stats *stats = this_cpu_ptr(vi->stats);
int capacity;
+ bool kick;
/* Free up any pending old buffers before queueing new ones. */
free_old_xmit_skbs(vi);
@@ -655,7 +695,17 @@ static netdev_tx_t start_xmit(struct sk_buff *skb, struct
net_device *dev)
kfree_skb(skb);
return NETDEV_TX_OK;
}
- virtqueue_kick(vi->svq);
+
+ kick = virtqueue_kick_prepare(vi->svq);
+ if (unlikely(kick))
+ virtqueue_notify(vi->svq);
+
+ u64_stats_update_begin(&stats->syncp);
+ if (unlikely(kick))
+ stats->data[VIRTNET_TX_KICKS]++;
+ stats->data[VIRTNET_TX_Q_BYTES] += skb->len;
+ stats->data[VIRTNET_TX_Q_PACKETS]++;
+ u64_stats_update_end(&stats->syncp);
/* Don't wait up for transmitted skbs to be freed. */
skb_orphan(skb);
@@ -943,10 +993,71 @@ static void virtnet_get_drvinfo(struct net_device *dev,
}
+static void virtnet_get_strings(struct net_device *dev, u32 stringset, u8 *buf)
+{
+ int i, cpu;
+ switch (stringset) {
+ case ETH_SS_STATS:
+ for_each_possible_cpu(cpu)
+ for (i = 0; i < VIRTNET_NUM_STATS; i++) {
+ sprintf(buf, "%s[%u]",
+ virtnet_stats_str_attr[i].string, cpu);
+ buf += ETH_GSTRING_LEN;
+ }
+ for (i = 0; i < VIRTNET_NUM_STATS; i++) {
+ memcpy(buf, virtnet_stats_str_attr[i].string,
+ ETH_GSTRING_LEN);
+ buf += ETH_GSTRING_LEN;
+ }
+ break;
+ }
+}
+
+static int virtnet_get_sset_count(struct net_device *dev, int sset)
+{
+ switch (sset) {
+ case ETH_SS_STATS:
+ return VIRTNET_NUM_STATS * (num_possible_cpus() + 1);
+ default:
+ return -EOPNOTSUPP;
+ }
+}
+
+static void virtnet_get_ethtool_stats(struct net_device *dev,
+ struct ethtool_stats *stats, u64 *buf)
+{
+ struct virtnet_info *vi = netdev_priv(dev);
+ int cpu, i;
+ unsigned int start;
+ struct virtnet_stats sample, total;
+
+ memset(&total, 0, sizeof(total));
+
+ for_each_possible_cpu(cpu) {
+ struct virtnet_stats *s = per_cpu_ptr(vi->stats, cpu);
+ do {
+ start = u64_stats_fetch_begin(&s->syncp);
+ memcpy(&sample.data, &s->data,
+ sizeof(u64) * VIRTNET_NUM_STATS);
+ } while (u64_stats_fetch_retry(&s->syncp, start));
+
+ for (i = 0; i < VIRTNET_NUM_STATS; i++) {
+ *buf = sample.data[i];
+ total.data[i] += sample.data[i];
+ buf++;
+ }
+ }
+
+ memcpy(buf, &total.data, sizeof(u64) * VIRTNET_NUM_STATS);
+}
+
static const struct ethtool_ops virtnet_ethtool_ops = {
.get_drvinfo = virtnet_get_drvinfo,
.get_link = ethtool_op_get_link,
.get_ringparam = virtnet_get_ringparam,
+ .get_ethtool_stats = virtnet_get_ethtool_stats,
+ .get_strings = virtnet_get_strings,
+ .get_sset_count = virtnet_get_sset_count,
};
#define MIN_MTU 68
Eric Dumazet
2012-Jun-06 08:22 UTC
[V2 RFC net-next PATCH 1/2] virtio_net: convert the statistics into array
On Wed, 2012-06-06 at 15:52 +0800, Jason Wang wrote:> Currently, we store the statistics in the independent fields of virtnet_stats, > this is not scalable when we want to add more counters. As suggested by Michael, > this patch convert it to an array and use the enum as the index to access them. > > Signed-off-by: Jason Wang <jasowang at redhat.com> > --- > drivers/net/virtio_net.c | 30 +++++++++++++++++------------- > 1 files changed, 17 insertions(+), 13 deletions(-) >> struct virtnet_stats { > struct u64_stats_sync syncp; > - u64 tx_bytes; > - u64 tx_packets; > - > - u64 rx_bytes; > - u64 rx_packets; > + u64 data[VIRTNET_NUM_STATS]; > }; >Interesting, but I fear you'll have a lot of problems. Current code is buggy, and you are adding more possible races. We could have one cpu doing the : u64_stats_update_begin(&stats->syncp); stats->rx_bytes += skb->len; stats->rx_packets++; u64_stats_update_end(&stats->syncp); And another one doing : u64_stats_update_begin(&stats->syncp); stats->tx_bytes += skb->len; stats->tx_packets++; u64_stats_update_end(&stats->syncp); And one syncp sequence increment can be lost, since both cpus are basically doing this at the same time : write_seqcount_begin(&syncp->seq); I'll send a fix in a separate thread.
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