Messages in this thread | | | From | Po-Yu Chuang <> | Date | Fri, 25 Feb 2011 17:45:40 +0800 | Subject | Re: [PATCH ref0] net: add Faraday FTMAC100 10/100 Ethernet driver |
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Hi Eric,
On Fri, Feb 25, 2011 at 10:32 AM, Po-Yu Chuang <ratbert.chuang@gmail.com> wrote: > On Fri, Feb 25, 2011 at 1:48 AM, Eric Dumazet <eric.dumazet@gmail.com> wrote: >> Le jeudi 24 février 2011 à 18:39 +0100, Eric Dumazet a écrit : >>> Le jeudi 24 février 2011 à 17:29 +0800, Po-Yu Chuang a écrit : >>> > From: Po-Yu Chuang <ratbert@faraday-tech.com> >>> > + >>> > +static bool ftmac100_rx_packet(struct ftmac100 *priv, int *processed) >>> > +{ >>> > + struct net_device *netdev = priv->netdev; >>> > + struct ftmac100_rxdes *rxdes; >>> > + struct sk_buff *skb; >>> > + struct page *page; >>> > + dma_addr_t map; >>> > + int length; >>> > + >>> > + rxdes = ftmac100_rx_locate_first_segment(priv); >>> > + if (!rxdes) >>> > + return false; >>> > + >>> > + if (unlikely(ftmac100_rx_packet_error(priv, rxdes))) { >>> > + ftmac100_rx_drop_packet(priv); >>> > + return true; >>> > + } >>> > + >>> > + /* >>> > + * It is impossible to get multi-segment packets >>> > + * because we always provide big enough receive buffers. >>> > + */ >>> > + if (unlikely(!ftmac100_rxdes_last_segment(rxdes))) >>> > + BUG(); >>> > + >>> > + /* start processing */ >>> > + skb = netdev_alloc_skb_ip_align(netdev, ETH_HLEN); >>> >>> Oh I see... You should allocate a bigger head (say... 128 bytes) >>> >>> And copy in it up to 128 bytes of first part... this to avoid upper >>> stack to reallocate skb head (because IP/TCP processing need to get >>> their headers in skb head) >> >> Take a look at drivers/net/niu.c : >> >> #define RX_SKB_ALLOC_SIZE 128 + NET_IP_ALIGN >> >> static int niu_process_rx_pkt(...) >> { >> ... >> skb = netdev_alloc_skb(np->dev, RX_SKB_ALLOC_SIZE); >> ... >> while (1) { >> ... >> niu_rx_skb_append(skb, page, off, append_size); >> } >> } > > Oh I got it. > > I will try this and redo the benchmarking.
It's a little faster than v5 now. Thanks. I will submit the current version later.
One more question just curious, why 128 bytes?
best regards, Po-Yu Chuang -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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