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Message-Id: <1431590425-23889-1-git-send-email-sixiao@microsoft.com>
Date: Thu, 14 May 2015 01:00:25 -0700
From: Simon Xiao <sixiao@...rosoft.com>
To: kys@...rosoft.com, haiyangz@...rosoft.com,
devel@...uxdriverproject.org, netdev@...r.kernel.org,
linux-kernel@...r.kernel.org
Cc: Simon Xiao <sixiao@...rosoft.com>
Subject: [PATCH net-next,v2,1/1] hv_netvsc: use per_cpu stats to calculate TX/RX data
Current code does not lock anything when calculating the TX and RX stats.
As a result, the RX and TX data reported by ifconfig are not accuracy in a
system with high network throughput and multiple CPUs (in my test,
RX/TX = 83% between 2 HyperV VM nodes which have 8 vCPUs and 40G Ethernet).
This patch fixed the above issue by using per_cpu stats.
netvsc_get_stats64() summarizes TX and RX data by iterating over all CPUs
to get their respective stats.
This v2 patch addressed David's comments on the cleanup path when
netdev_alloc_pcpu_stats() failed.
Signed-off-by: Simon Xiao <sixiao@...rosoft.com>
Reviewed-by: K. Y. Srinivasan <kys@...rosoft.com>
Reviewed-by: Haiyang Zhang <haiyangz@...rosoft.com>
---
drivers/net/hyperv/hyperv_net.h | 9 +++++
drivers/net/hyperv/netvsc_drv.c | 85 +++++++++++++++++++++++++++++++++++++----
2 files changed, 86 insertions(+), 8 deletions(-)
diff --git a/drivers/net/hyperv/hyperv_net.h b/drivers/net/hyperv/hyperv_net.h
index 41071d3..5a92b36 100644
--- a/drivers/net/hyperv/hyperv_net.h
+++ b/drivers/net/hyperv/hyperv_net.h
@@ -611,6 +611,12 @@ struct multi_send_data {
u32 count; /* counter of batched packets */
};
+struct netvsc_stats {
+ u64 packets;
+ u64 bytes;
+ struct u64_stats_sync s_sync;
+};
+
/* The context of the netvsc device */
struct net_device_context {
/* point back to our device context */
@@ -618,6 +624,9 @@ struct net_device_context {
struct delayed_work dwork;
struct work_struct work;
u32 msg_enable; /* debug level */
+
+ struct netvsc_stats __percpu *tx_stats;
+ struct netvsc_stats __percpu *rx_stats;
};
/* Per netvsc device */
diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c
index 5993c7e..1570628 100644
--- a/drivers/net/hyperv/netvsc_drv.c
+++ b/drivers/net/hyperv/netvsc_drv.c
@@ -391,7 +391,7 @@ static int netvsc_start_xmit(struct sk_buff *skb, struct net_device *net)
u32 skb_length;
u32 pkt_sz;
struct hv_page_buffer page_buf[MAX_PAGE_BUFFER_COUNT];
-
+ struct netvsc_stats *tx_stats = this_cpu_ptr(net_device_ctx->tx_stats);
/* We will atmost need two pages to describe the rndis
* header. We can only transmit MAX_PAGE_BUFFER_COUNT number
@@ -580,8 +580,10 @@ do_send:
drop:
if (ret == 0) {
- net->stats.tx_bytes += skb_length;
- net->stats.tx_packets++;
+ u64_stats_update_begin(&tx_stats->s_sync);
+ tx_stats->packets++;
+ tx_stats->bytes += skb_length;
+ u64_stats_update_end(&tx_stats->s_sync);
} else {
if (ret != -EAGAIN) {
dev_kfree_skb_any(skb);
@@ -644,13 +646,17 @@ int netvsc_recv_callback(struct hv_device *device_obj,
struct ndis_tcp_ip_checksum_info *csum_info)
{
struct net_device *net;
+ struct net_device_context *net_device_ctx;
struct sk_buff *skb;
+ struct netvsc_stats *rx_stats;
net = ((struct netvsc_device *)hv_get_drvdata(device_obj))->ndev;
if (!net || net->reg_state != NETREG_REGISTERED) {
packet->status = NVSP_STAT_FAIL;
return 0;
}
+ net_device_ctx = netdev_priv(net);
+ rx_stats = this_cpu_ptr(net_device_ctx->rx_stats);
/* Allocate a skb - TODO direct I/O to pages? */
skb = netdev_alloc_skb_ip_align(net, packet->total_data_buflen);
@@ -686,8 +692,10 @@ int netvsc_recv_callback(struct hv_device *device_obj,
skb_record_rx_queue(skb, packet->channel->
offermsg.offer.sub_channel_index);
- net->stats.rx_packets++;
- net->stats.rx_bytes += packet->total_data_buflen;
+ u64_stats_update_begin(&rx_stats->s_sync);
+ rx_stats->packets++;
+ rx_stats->bytes += packet->total_data_buflen;
+ u64_stats_update_end(&rx_stats->s_sync);
/*
* Pass the skb back up. Network stack will deallocate the skb when it
@@ -753,6 +761,46 @@ static int netvsc_change_mtu(struct net_device *ndev, int mtu)
return 0;
}
+static struct rtnl_link_stats64 *netvsc_get_stats64(struct net_device *net,
+ struct rtnl_link_stats64 *t)
+{
+ struct net_device_context *ndev_ctx = netdev_priv(net);
+ int cpu;
+
+ for_each_possible_cpu(cpu) {
+ struct netvsc_stats *tx_stats = per_cpu_ptr(ndev_ctx->tx_stats,
+ cpu);
+ struct netvsc_stats *rx_stats = per_cpu_ptr(ndev_ctx->rx_stats,
+ cpu);
+ u64 tx_packets, tx_bytes, rx_packets, rx_bytes;
+ unsigned int start;
+
+ do {
+ start = u64_stats_fetch_begin_irq(&tx_stats->s_sync);
+ tx_packets = tx_stats->packets;
+ tx_bytes = tx_stats->bytes;
+ } while (u64_stats_fetch_retry_irq(&tx_stats->s_sync, start));
+
+ do {
+ start = u64_stats_fetch_begin_irq(&rx_stats->s_sync);
+ rx_packets = rx_stats->packets;
+ rx_bytes = rx_stats->bytes;
+ } while (u64_stats_fetch_retry_irq(&rx_stats->s_sync, start));
+
+ t->tx_bytes += tx_bytes;
+ t->tx_packets += tx_packets;
+ t->rx_bytes += rx_bytes;
+ t->rx_packets += rx_packets;
+ }
+
+ t->tx_dropped = net->stats.tx_dropped;
+ t->tx_errors = net->stats.tx_dropped;
+
+ t->rx_dropped = net->stats.rx_dropped;
+ t->rx_errors = net->stats.rx_errors;
+
+ return t;
+}
static int netvsc_set_mac_addr(struct net_device *ndev, void *p)
{
@@ -804,6 +852,7 @@ static const struct net_device_ops device_ops = {
.ndo_validate_addr = eth_validate_addr,
.ndo_set_mac_address = netvsc_set_mac_addr,
.ndo_select_queue = netvsc_select_queue,
+ .ndo_get_stats64 = netvsc_get_stats64,
#ifdef CONFIG_NET_POLL_CONTROLLER
.ndo_poll_controller = netvsc_poll_controller,
#endif
@@ -855,6 +904,14 @@ static void netvsc_link_change(struct work_struct *w)
netdev_notify_peers(net);
}
+static void netvsc_free_netdev(struct net_device *netdev)
+{
+ struct net_device_context *net_device_ctx = netdev_priv(netdev);
+
+ free_percpu(net_device_ctx->tx_stats);
+ free_percpu(net_device_ctx->rx_stats);
+ free_netdev(netdev);
+}
static int netvsc_probe(struct hv_device *dev,
const struct hv_vmbus_device_id *dev_id)
@@ -883,6 +940,18 @@ static int netvsc_probe(struct hv_device *dev,
netdev_dbg(net, "netvsc msg_enable: %d\n",
net_device_ctx->msg_enable);
+ net_device_ctx->tx_stats = netdev_alloc_pcpu_stats(struct netvsc_stats);
+ if (!net_device_ctx->tx_stats) {
+ free_netdev(net);
+ return -ENOMEM;
+ }
+ net_device_ctx->rx_stats = netdev_alloc_pcpu_stats(struct netvsc_stats);
+ if (!net_device_ctx->rx_stats) {
+ free_percpu(net_device_ctx->tx_stats);
+ free_netdev(net);
+ return -ENOMEM;
+ }
+
hv_set_drvdata(dev, net);
INIT_DELAYED_WORK(&net_device_ctx->dwork, netvsc_link_change);
INIT_WORK(&net_device_ctx->work, do_set_multicast);
@@ -909,7 +978,7 @@ static int netvsc_probe(struct hv_device *dev,
ret = rndis_filter_device_add(dev, &device_info);
if (ret != 0) {
netdev_err(net, "unable to add netvsc device (ret %d)\n", ret);
- free_netdev(net);
+ netvsc_free_netdev(net);
hv_set_drvdata(dev, NULL);
return ret;
}
@@ -923,7 +992,7 @@ static int netvsc_probe(struct hv_device *dev,
if (ret != 0) {
pr_err("Unable to register netdev.\n");
rndis_filter_device_remove(dev);
- free_netdev(net);
+ netvsc_free_netdev(net);
} else {
schedule_delayed_work(&net_device_ctx->dwork, 0);
}
@@ -962,7 +1031,7 @@ static int netvsc_remove(struct hv_device *dev)
*/
rndis_filter_device_remove(dev);
- free_netdev(net);
+ netvsc_free_netdev(net);
return 0;
}
--
1.8.5.2
--
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