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Date: Fri, 27 Dec 2013 21:12:37 +0100 (CET) From: Julia Lawall <julia.lawall@...6.fr> To: Joe Perches <joe@...ches.com> cc: Eric Dumazet <eric.dumazet@...il.com>, Julia Lawall <julia.lawall@...6.fr>, Ding Tianhong <dingtianhong@...wei.com>, "David S. Miller" <davem@...emloft.net>, Netdev <netdev@...r.kernel.org>, "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org> Subject: Re: [PATCH net-next 19/20] net: plip: slight optimization of addr compare On Fri, 27 Dec 2013, Joe Perches wrote: > On Fri, 2013-12-27 at 07:48 -0800, Eric Dumazet wrote: > > On Fri, 2013-12-27 at 14:49 +0800, Ding Tianhong wrote: > > > Use possibly more efficient ether_addr_equal > > > to instead of memcmp. > [] > > > diff --git a/drivers/net/plip/plip.c b/drivers/net/plip/plip.c > [] > > > @@ -549,7 +549,7 @@ static __be16 plip_type_trans(struct sk_buff *skb, struct net_device *dev) > > > > > > if(*eth->h_dest&1) > > > { > > > - if(memcmp(eth->h_dest,dev->broadcast, ETH_ALEN)==0) > > > + if(ether_addr_equal(eth->h_dest, dev->broadcast)) > > > skb->pkt_type=PACKET_BROADCAST; > > > else > > > skb->pkt_type=PACKET_MULTICAST; > > > > What about : > > > > if (is_multicast_ether_addr(eth->h_dest)) { > > if (ether_addr_equal_64bits(eth->h_dest, dev->broadcast)) > > skb->pkt_type = PACKET_BROADCAST; > > else > > skb->pkt_type = PACKET_MULTICAST; > > } > > That is better though I wonder how many systems are > still using laplink via parallel null-printer cables. > > No matter, better is better. > > The same optimization using ether_addr_equal_64bits > may be possible to do in other places given other > structs too. > > Perhaps it's a possible spatch/coccinelle conversion, > > I don't know spatch well enough to know if a > mechanism to check if structure members have other > fields that follow them in the structure or if the > structure member is an array of a minimum size. > > Maybe Julia does. (cc'd) I'm not sure to competely understand the issues. Could you explain more? thanks, julia -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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