Re: [PATCH net v3 8/9] forcedeth: 64-bit stats

[Eric Dumazet]

Le vendredi 04 novembre 2011 Ã 18:53 -0700, David Decotigny a Ãcrit :
> This converts forcedeth stats to be 64-bits. It also improves
> accounting for dropped rx frames.
> 
> Tested:
>   16-way SMP x86_64 ->
>   RX bytes:7244556582 (7.2 GB)  TX bytes:181904254 (181.9 MB)
> 
> 

This changelog and patch title are misleading.

On a 32bit x86, stats are still 32bit wide after your patch.

On a 64bit x86_64, stats were already 64bit wide before your patch.

So the real thing is about not using the embedded netdevice dev->stats
structure, to reduce false sharing.

> 
> Signed-off-by: David Decotigny <david.decotigny@xxxxxxxxxx>
> ---
>  drivers/net/ethernet/nvidia/forcedeth.c |   69 +++++++++++++++++++-----------
>  1 files changed, 44 insertions(+), 25 deletions(-)
> 
> diff --git a/drivers/net/ethernet/nvidia/forcedeth.c b/drivers/net/ethernet/nvidia/forcedeth.c
> index 90cdf26..08c512b 100644
> --- a/drivers/net/ethernet/nvidia/forcedeth.c
> +++ b/drivers/net/ethernet/nvidia/forcedeth.c
> @@ -799,6 +799,8 @@ struct fe_priv {
>  	struct timer_list stats_poll;
>  	u32 nic_poll_irq;
>  	int rx_ring_size;
> +	unsigned long stats_rx_dropped;
> +	unsigned long stats_rx_missed_errors;
>  
>  	/* media detection workaround.
>  	 * Locking: Within irq hander or disable_irq+spin_lock(&np->lock);
> @@ -821,6 +823,7 @@ struct fe_priv {
>  	struct nv_skb_map *tx_change_owner;
>  	struct nv_skb_map *tx_end_flip;
>  	int tx_stop;
> +	unsigned long stats_tx_dropped;
>  
>  	/* msi/msi-x fields */
>  	u32 msi_flags;
> @@ -1700,33 +1703,47 @@ static void nv_get_hw_stats(struct net_device *dev)
>  }
>  
>  /*
> - * nv_get_stats: dev->get_stats function
> + * nv_get_stats: dev->ndo_get_stats64 function
>   * Get latest stats value from the nic.
>   * Called with read_lock(&dev_base_lock) held for read -
>   * only synchronized against unregister_netdevice.
>   */
> -static struct net_device_stats *nv_get_stats(struct net_device *dev)
> +static struct rtnl_link_stats64*
> +nv_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *storage)
>  {
>  	struct fe_priv *np = netdev_priv(dev);
>  
>  	/* If the nic supports hw counters then retrieve latest values */
> -	if (np->driver_data & (DEV_HAS_STATISTICS_V1|DEV_HAS_STATISTICS_V2|DEV_HAS_STATISTICS_V3)) {
> +	if (np->driver_data & (DEV_HAS_STATISTICS_V1
> +			       | DEV_HAS_STATISTICS_V2
> +			       | DEV_HAS_STATISTICS_V3)) {
>  		nv_get_hw_stats(dev);
>  
> -		/* copy to net_device stats */
> -		dev->stats.tx_packets = np->estats.tx_packets;
> -		dev->stats.rx_bytes = np->estats.rx_bytes;
> -		dev->stats.tx_bytes = np->estats.tx_bytes;
> -		dev->stats.tx_fifo_errors = np->estats.tx_fifo_errors;
> -		dev->stats.tx_carrier_errors = np->estats.tx_carrier_errors;
> -		dev->stats.rx_crc_errors = np->estats.rx_crc_errors;
> -		dev->stats.rx_over_errors = np->estats.rx_over_errors;
> -		dev->stats.rx_fifo_errors = np->estats.rx_drop_frame;
> -		dev->stats.rx_errors = np->estats.rx_errors_total;
> -		dev->stats.tx_errors = np->estats.tx_errors_total;
> -	}
> -
> -	return &dev->stats;
> +		/* generic stats */
> +		storage->rx_packets = np->estats.rx_packets;
> +		storage->tx_packets = np->estats.tx_packets;
> +		storage->rx_bytes   = np->estats.rx_bytes;
> +		storage->tx_bytes   = np->estats.tx_bytes;
> +		storage->rx_errors  = np->estats.rx_errors_total;
> +		storage->tx_errors  = np->estats.tx_errors_total;
> +		storage->rx_dropped = np->stats_rx_dropped;
> +		storage->tx_dropped = np->stats_tx_dropped;
> +		storage->multicast  = np->estats.rx_multicast;
> +
> +		/* detailed rx_errors */
> +		storage->rx_length_errors = np->estats.rx_length_error;
> +		storage->rx_over_errors   = np->estats.rx_over_errors;
> +		storage->rx_crc_errors    = np->estats.rx_crc_errors;
> +		storage->rx_frame_errors  = np->estats.rx_frame_align_error;
> +		storage->rx_fifo_errors   = np->estats.rx_drop_frame;
> +		storage->rx_missed_errors = np->stats_rx_missed_errors;
> +
> +		/* detailed tx_errors */
> +		storage->tx_carrier_errors = np->estats.tx_carrier_errors;
> +		storage->tx_fifo_errors    = np->estats.tx_fifo_errors;
> +	}
> +
> +	return storage;
>  }
>  
>  /*
> @@ -1759,8 +1776,10 @@ static int nv_alloc_rx(struct net_device *dev)
>  				np->put_rx.orig = np->first_rx.orig;
>  			if (unlikely(np->put_rx_ctx++ == np->last_rx_ctx))
>  				np->put_rx_ctx = np->first_rx_ctx;
> -		} else
> +		} else {
> +			np->stats_rx_dropped++;
>  			return 1;
> +		}
>  	}
>  	return 0;
>  }
> @@ -1791,8 +1810,10 @@ static int nv_alloc_rx_optimized(struct net_device *dev)
>  				np->put_rx.ex = np->first_rx.ex;
>  			if (unlikely(np->put_rx_ctx++ == np->last_rx_ctx))
>  				np->put_rx_ctx = np->first_rx_ctx;
> -		} else
> +		} else {
> +			np->stats_rx_dropped++;
>  			return 1;
> +		}
>  	}
>  	return 0;
>  }
> @@ -1928,7 +1949,7 @@ static void nv_drain_tx(struct net_device *dev)
>  			np->tx_ring.ex[i].buflow = 0;
>  		}
>  		if (nv_release_txskb(np, &np->tx_skb[i]))
> -			dev->stats.tx_dropped++;
> +			np->stats_tx_dropped++;
>  		np->tx_skb[i].dma = 0;
>  		np->tx_skb[i].dma_len = 0;
>  		np->tx_skb[i].dma_single = 0;
> @@ -2651,7 +2672,7 @@ static int nv_rx_process(struct net_device *dev, int limit)
>  					/* the rest are hard errors */
>  					else {
>  						if (flags & NV_RX_MISSEDFRAME)
> -							dev->stats.rx_missed_errors++;
> +							np->stats_rx_missed_errors++;
>  						dev_kfree_skb(skb);
>  						goto next_pkt;
>  					}
> @@ -2694,7 +2715,6 @@ static int nv_rx_process(struct net_device *dev, int limit)
>  		skb_put(skb, len);
>  		skb->protocol = eth_type_trans(skb, dev);
>  		napi_gro_receive(&np->napi, skb);
> -		dev->stats.rx_packets++;
>  next_pkt:
>  		if (unlikely(np->get_rx.orig++ == np->last_rx.orig))
>  			np->get_rx.orig = np->first_rx.orig;
> @@ -2777,7 +2797,6 @@ static int nv_rx_process_optimized(struct net_device *dev, int limit)
>  				__vlan_hwaccel_put_tag(skb, vid);
>  			}
>  			napi_gro_receive(&np->napi, skb);
> -			dev->stats.rx_packets++;
>  		} else {
>  			dev_kfree_skb(skb);
>  		}
> @@ -5199,7 +5218,7 @@ static int nv_close(struct net_device *dev)
>  static const struct net_device_ops nv_netdev_ops = {
>  	.ndo_open		= nv_open,
>  	.ndo_stop		= nv_close,
> -	.ndo_get_stats		= nv_get_stats,
> +	.ndo_get_stats64	= nv_get_stats64,
>  	.ndo_start_xmit		= nv_start_xmit,
>  	.ndo_tx_timeout		= nv_tx_timeout,
>  	.ndo_change_mtu		= nv_change_mtu,
> @@ -5216,7 +5235,7 @@ static const struct net_device_ops nv_netdev_ops = {
>  static const struct net_device_ops nv_netdev_ops_optimized = {
>  	.ndo_open		= nv_open,
>  	.ndo_stop		= nv_close,
> -	.ndo_get_stats		= nv_get_stats,
> +	.ndo_get_stats64	= nv_get_stats64,
>  	.ndo_start_xmit		= nv_start_xmit_optimized,
>  	.ndo_tx_timeout		= nv_tx_timeout,
>  	.ndo_change_mtu		= nv_change_mtu,


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/