Re: [PATCH net-next] r8169: Add 64bit statistics

Francois Romieu
2012-03-04T23:25:34Z

Eric Dumazet <eric.dumazet@gmail.com> :
[...]
> small point : Using this means you have a 32bit hole here (on 32bit
> build). Its minor, you dont need to change.

Ok.

[...]
> You could try to put these somewhere else, to try to keep this portion
> as read only memory, to be more SMP friendly.
> (Some loaded server could have one CPU serving RX stuff, and other cpus
> doing TX stuff)

Point taken. It could make sense to rework the rtl8169_private struct a bit
more.

[...]
> > @@ -6070,20 +6084,49 @@ static void rtl_set_rx_mode(struct net_device *dev)
> > }
> >
> > /**
> > - * rtl8169_get_stats - Get rtl8169 read/write statistics
> > + * rtl8169_get_stats64 - Get rtl8169 read/write statistics
> > * @dev: The Ethernet Device to get statistics for
>
> missing @stats

This documentation is almost useless anyway. I removed it.

[...]
> You dont need _bytes and _packets temp variables, as @stats points to a
> private memory, we can use it as working storage, just do :
>
> do {
> start = u64_stats_fetch_begin_bh(&tp->rx_stats.syncp);
> stats->rx_packets = tp->rx_stats.packets;
> stats->rx_bytes = tp->rx_stats.bytes;
> } while (u64_stats_fetch_retry_bh(&tp->rx_stats.syncp, start));

It should give something like the patch below.

If I understand correctly we do not care much about the error counters,
right ?

From: Junchang Wang <junchangwang@gmail.com>
Date: Sun, 4 Mar 2012 23:30:32 +0100
Subject: [PATCH 1/2] r8169: add 64bit statistics.

Switch to use ndo_get_stats64 to get 64bit statistics.
Two sync entries are used (one for Rx and one for Tx).

Signed-off-by: Junchang Wang <junchangwang@gmail.com>
Reviewed-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Francois Romieu <romieu@fr.zoreil.com>
---
drivers/net/ethernet/realtek/r8169.c | 59 ++++++++++++++++++++++++++--------
1 files changed, 45 insertions(+), 14 deletions(-)

diff --git a/drivers/net/ethernet/realtek/r8169.c b/drivers/net/ethernet/realtek/r8169.c
index fbd855b..a4d7674 100644
--- a/drivers/net/ethernet/realtek/r8169.c
+++ b/drivers/net/ethernet/realtek/r8169.c
@@ -675,6 +675,12 @@ enum rtl_flag {
RTL_FLAG_MAX
};

+struct rtl8169_stats {
+ u64 packets;
+ u64 bytes;
+ struct u64_stats_sync syncp;
+};
+
struct rtl8169_private {
void __iomem *mmio_addr; /* memory map physical address */
struct pci_dev *pci_dev;
@@ -687,6 +693,8 @@ struct rtl8169_private {
u32 cur_tx; /* Index into the Tx descriptor buffer of next Rx pkt. */
u32 dirty_rx;
u32 dirty_tx;
+ struct rtl8169_stats rx_stats;
+ struct rtl8169_stats tx_stats;
struct TxDesc *TxDescArray; /* 256-aligned Tx descriptor ring */
struct RxDesc *RxDescArray; /* 256-aligned Rx descriptor ring */
dma_addr_t TxPhyAddr;
@@ -775,7 +783,9 @@ static void rtl_hw_start(struct net_device *dev);
static int rtl8169_close(struct net_device *dev);
static void rtl_set_rx_mode(struct net_device *dev);
static void rtl8169_tx_timeout(struct net_device *dev);
-static struct net_device_stats *rtl8169_get_stats(struct net_device *dev);
+static struct rtnl_link_stats64 *rtl8169_get_stats64(struct net_device *dev,
+ struct rtnl_link_stats64
+ *stats);
static int rtl8169_change_mtu(struct net_device *dev, int new_mtu);
static void rtl8169_rx_clear(struct rtl8169_private *tp);
static int rtl8169_poll(struct napi_struct *napi, int budget);
@@ -3521,7 +3531,7 @@ static void rtl_disable_msi(struct pci_dev *pdev, struct rtl8169_private *tp)
static const struct net_device_ops rtl8169_netdev_ops = {
.ndo_open = rtl8169_open,
.ndo_stop = rtl8169_close,
- .ndo_get_stats = rtl8169_get_stats,
+ .ndo_get_stats64 = rtl8169_get_stats64,
.ndo_start_xmit = rtl8169_start_xmit,
.ndo_tx_timeout = rtl8169_tx_timeout,
.ndo_validate_addr = eth_validate_addr,
@@ -5658,8 +5668,10 @@ static void rtl_tx(struct net_device *dev, struct rtl8169_private *tp)
rtl8169_unmap_tx_skb(&tp->pci_dev->dev, tx_skb,
tp->TxDescArray + entry);
if (status & LastFrag) {
- dev->stats.tx_packets++;
- dev->stats.tx_bytes += tx_skb->skb->len;
+ u64_stats_update_begin(&tp->tx_stats.syncp);
+ tp->tx_stats.packets++;
+ tp->tx_stats.bytes += tx_skb->skb->len;
+ u64_stats_update_end(&tp->tx_stats.syncp);
dev_kfree_skb(tx_skb->skb);
tx_skb->skb = NULL;
}
@@ -5807,8 +5819,10 @@ process_pkt:

napi_gro_receive(&tp->napi, skb);

- dev->stats.rx_bytes += pkt_size;
- dev->stats.rx_packets++;
+ u64_stats_update_begin(&tp->rx_stats.syncp);
+ tp->rx_stats.packets++;
+ tp->rx_stats.bytes += pkt_size;
+ u64_stats_update_end(&tp->rx_stats.syncp);
}

/* Work around for AMD plateform. */
@@ -6069,21 +6083,38 @@ static void rtl_set_rx_mode(struct net_device *dev)
RTL_W32(RxConfig, tmp);
}

-/**
- * rtl8169_get_stats - Get rtl8169 read/write statistics
- * @dev: The Ethernet Device to get statistics for
- *
- * Get TX/RX statistics for rtl8169
- */
-static struct net_device_stats *rtl8169_get_stats(struct net_device *dev)
+static struct rtnl_link_stats64 *
+rtl8169_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats)
{
struct rtl8169_private *tp = netdev_priv(dev);
void __iomem *ioaddr = tp->mmio_addr;
+ unsigned int start;

if (netif_running(dev))
rtl8169_rx_missed(dev, ioaddr);

- return &dev->stats;
+ do {
+ start = u64_stats_fetch_begin_bh(&tp->rx_stats.syncp);
+ stats->rx_packets = tp->rx_stats.packets;
+ stats->rx_bytes = tp->rx_stats.bytes;
+ } while (u64_stats_fetch_retry_bh(&tp->rx_stats.syncp, start));
+
+
+ do {
+ start = u64_stats_fetch_begin_bh(&tp->tx_stats.syncp);
+ stats->tx_packets = tp->tx_stats.packets;
+ stats->tx_bytes = tp->tx_stats.bytes;
+ } while (u64_stats_fetch_retry_bh(&tp->tx_stats.syncp, start));
+
+ stats->rx_dropped = dev->stats.rx_dropped;
+ stats->tx_dropped = dev->stats.tx_dropped;
+ stats->rx_length_errors = dev->stats.rx_length_errors;
+ stats->rx_errors = dev->stats.rx_errors;
+ stats->rx_crc_errors = dev->stats.rx_crc_errors;
+ stats->rx_fifo_errors = dev->stats.rx_fifo_errors;
+ stats->rx_missed_errors = dev->stats.rx_missed_errors;
+
+ return stats;
}

static void rtl8169_net_suspend(struct net_device *dev)
--
1.7.7.6