[PATCH] hv_netvsc: Add per-cpu ethtool stats for netvsc

From: Yidong Ren
Date: Wed Jun 06 2018 - 18:28:48 EST


From: Yidong Ren <yidren@xxxxxxxxxxxxx>

This patch implements following ethtool stats fields for netvsc:
cpu<n>_tx/rx_packets/bytes
cpu<n>_vf_tx/rx_packets/bytes

Corresponding per-cpu counters exist in current code. Exposing these
counters will help troubleshooting performance issues.

Signed-off-by: Yidong Ren <yidren@xxxxxxxxxxxxx>
---
drivers/net/hyperv/hyperv_net.h | 11 ++++
drivers/net/hyperv/netvsc_drv.c | 104 +++++++++++++++++++++++++++++++-
2 files changed, 113 insertions(+), 2 deletions(-)

diff --git a/drivers/net/hyperv/hyperv_net.h b/drivers/net/hyperv/hyperv_net.h
index 960f06141472..f8c798bf9418 100644
--- a/drivers/net/hyperv/hyperv_net.h
+++ b/drivers/net/hyperv/hyperv_net.h
@@ -710,6 +710,17 @@ struct netvsc_ethtool_stats {
unsigned long wake_queue;
};

+struct netvsc_ethtool_pcpu_stats {
+ u64 rx_packets;
+ u64 rx_bytes;
+ u64 tx_packets;
+ u64 tx_bytes;
+ u64 vf_rx_packets;
+ u64 vf_rx_bytes;
+ u64 vf_tx_packets;
+ u64 vf_tx_bytes;
+};
+
struct netvsc_vf_pcpu_stats {
u64 rx_packets;
u64 rx_bytes;
diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c
index da07ccdf84bf..c43e64606c1a 100644
--- a/drivers/net/hyperv/netvsc_drv.c
+++ b/drivers/net/hyperv/netvsc_drv.c
@@ -1104,6 +1104,66 @@ static void netvsc_get_vf_stats(struct net_device *net,
}
}

+static void netvsc_get_pcpu_stats(struct net_device *net,
+ struct netvsc_ethtool_pcpu_stats
+ __percpu *pcpu_tot)
+{
+ struct net_device_context *ndev_ctx = netdev_priv(net);
+ struct netvsc_device *nvdev = rcu_dereference_rtnl(ndev_ctx->nvdev);
+ int i;
+
+ // fetch percpu stats of vf
+ for_each_possible_cpu(i) {
+ const struct netvsc_vf_pcpu_stats *stats =
+ per_cpu_ptr(ndev_ctx->vf_stats, i);
+ struct netvsc_ethtool_pcpu_stats *this_tot =
+ per_cpu_ptr(pcpu_tot, i);
+ unsigned int start;
+
+ do {
+ start = u64_stats_fetch_begin_irq(&stats->syncp);
+ this_tot->vf_rx_packets = stats->rx_packets;
+ this_tot->vf_tx_packets = stats->tx_packets;
+ this_tot->vf_rx_bytes = stats->rx_bytes;
+ this_tot->vf_tx_bytes = stats->tx_bytes;
+ } while (u64_stats_fetch_retry_irq(&stats->syncp, start));
+ this_tot->rx_packets = this_tot->vf_rx_packets;
+ this_tot->tx_packets = this_tot->vf_tx_packets;
+ this_tot->rx_bytes = this_tot->vf_rx_bytes;
+ this_tot->tx_bytes = this_tot->vf_tx_bytes;
+ }
+
+ // fetch percpu stats of netvsc
+ for (i = 0; i < nvdev->num_chn; i++) {
+ const struct netvsc_channel *nvchan = &nvdev->chan_table[i];
+ const struct netvsc_stats *stats;
+ struct netvsc_ethtool_pcpu_stats *this_tot =
+ per_cpu_ptr(pcpu_tot, nvchan->channel->target_cpu);
+ u64 packets, bytes;
+ unsigned int start;
+
+ stats = &nvchan->tx_stats;
+ do {
+ start = u64_stats_fetch_begin_irq(&stats->syncp);
+ packets = stats->packets;
+ bytes = stats->bytes;
+ } while (u64_stats_fetch_retry_irq(&stats->syncp, start));
+
+ this_tot->tx_bytes += bytes;
+ this_tot->tx_packets += packets;
+
+ stats = &nvchan->rx_stats;
+ do {
+ start = u64_stats_fetch_begin_irq(&stats->syncp);
+ packets = stats->packets;
+ bytes = stats->bytes;
+ } while (u64_stats_fetch_retry_irq(&stats->syncp, start));
+
+ this_tot->rx_bytes += bytes;
+ this_tot->rx_packets += packets;
+ }
+}
+
static void netvsc_get_stats64(struct net_device *net,
struct rtnl_link_stats64 *t)
{
@@ -1201,6 +1261,23 @@ static const struct {
{ "rx_no_memory", offsetof(struct netvsc_ethtool_stats, rx_no_memory) },
{ "stop_queue", offsetof(struct netvsc_ethtool_stats, stop_queue) },
{ "wake_queue", offsetof(struct netvsc_ethtool_stats, wake_queue) },
+}, pcpu_stats[] = {
+ { "cpu%u_rx_packets",
+ offsetof(struct netvsc_ethtool_pcpu_stats, rx_packets) },
+ { "cpu%u_rx_bytes",
+ offsetof(struct netvsc_ethtool_pcpu_stats, rx_bytes) },
+ { "cpu%u_tx_packets",
+ offsetof(struct netvsc_ethtool_pcpu_stats, tx_packets) },
+ { "cpu%u_tx_bytes",
+ offsetof(struct netvsc_ethtool_pcpu_stats, tx_bytes) },
+ { "cpu%u_vf_rx_packets",
+ offsetof(struct netvsc_ethtool_pcpu_stats, vf_rx_packets) },
+ { "cpu%u_vf_rx_bytes",
+ offsetof(struct netvsc_ethtool_pcpu_stats, vf_rx_bytes) },
+ { "cpu%u_vf_tx_packets",
+ offsetof(struct netvsc_ethtool_pcpu_stats, vf_tx_packets) },
+ { "cpu%u_vf_tx_bytes",
+ offsetof(struct netvsc_ethtool_pcpu_stats, vf_tx_bytes) },
}, vf_stats[] = {
{ "vf_rx_packets", offsetof(struct netvsc_vf_pcpu_stats, rx_packets) },
{ "vf_rx_bytes", offsetof(struct netvsc_vf_pcpu_stats, rx_bytes) },
@@ -1212,6 +1289,9 @@ static const struct {
#define NETVSC_GLOBAL_STATS_LEN ARRAY_SIZE(netvsc_stats)
#define NETVSC_VF_STATS_LEN ARRAY_SIZE(vf_stats)

+/* statistics per queue (rx/tx packets/bytes) */
+#define NETVSC_PCPU_STATS_LEN (num_present_cpus() * ARRAY_SIZE(pcpu_stats))
+
/* 4 statistics per queue (rx/tx packets/bytes) */
#define NETVSC_QUEUE_STATS_LEN(dev) ((dev)->num_chn * 4)

@@ -1227,6 +1307,7 @@ static int netvsc_get_sset_count(struct net_device *dev, int string_set)
case ETH_SS_STATS:
return NETVSC_GLOBAL_STATS_LEN
+ NETVSC_VF_STATS_LEN
+ + NETVSC_PCPU_STATS_LEN
+ NETVSC_QUEUE_STATS_LEN(nvdev);
default:
return -EINVAL;
@@ -1241,9 +1322,10 @@ static void netvsc_get_ethtool_stats(struct net_device *dev,
const void *nds = &ndc->eth_stats;
const struct netvsc_stats *qstats;
struct netvsc_vf_pcpu_stats sum;
+ struct netvsc_ethtool_pcpu_stats __percpu *pcpu_sum;
unsigned int start;
u64 packets, bytes;
- int i, j;
+ int i, j, cpu;

if (!nvdev)
return;
@@ -1255,6 +1337,17 @@ static void netvsc_get_ethtool_stats(struct net_device *dev,
for (j = 0; j < NETVSC_VF_STATS_LEN; j++)
data[i++] = *(u64 *)((void *)&sum + vf_stats[j].offset);

+ pcpu_sum = alloc_percpu(struct netvsc_ethtool_pcpu_stats);
+ netvsc_get_pcpu_stats(dev, pcpu_sum);
+ for_each_present_cpu(cpu) {
+ struct netvsc_ethtool_pcpu_stats *this_sum =
+ per_cpu_ptr(pcpu_sum, cpu);
+ for (j = 0; j < ARRAY_SIZE(pcpu_stats); j++)
+ data[i++] = *(u64 *)((void *)this_sum
+ + pcpu_stats[j].offset);
+ }
+ free_percpu(pcpu_sum);
+
for (j = 0; j < nvdev->num_chn; j++) {
qstats = &nvdev->chan_table[j].tx_stats;

@@ -1282,7 +1375,7 @@ static void netvsc_get_strings(struct net_device *dev, u32 stringset, u8 *data)
struct net_device_context *ndc = netdev_priv(dev);
struct netvsc_device *nvdev = rtnl_dereference(ndc->nvdev);
u8 *p = data;
- int i;
+ int i, cpu;

if (!nvdev)
return;
@@ -1299,6 +1392,13 @@ static void netvsc_get_strings(struct net_device *dev, u32 stringset, u8 *data)
p += ETH_GSTRING_LEN;
}

+ for_each_present_cpu(cpu) {
+ for (i = 0; i < ARRAY_SIZE(pcpu_stats); i++) {
+ sprintf(p, pcpu_stats[i].name, cpu);
+ p += ETH_GSTRING_LEN;
+ }
+ }
+
for (i = 0; i < nvdev->num_chn; i++) {
sprintf(p, "tx_queue_%u_packets", i);
p += ETH_GSTRING_LEN;
--
2.17.1