From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ding Tianhong Subject: Re: [PATCH net-next] vlan: use ether_addr_equal_64bits to instead of ether_addr_equal Date: Mon, 3 Mar 2014 14:05:15 +0800 Message-ID: <53141B9B.40404@huawei.com> References: <5313D77F.3090508@huawei.com> <1393811384.13719.47.camel@joe-AO722> <5313EDC0.6020701@huawei.com> <1393821407.13719.65.camel@joe-AO722> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: Patrick McHardy , "David S. Miller" , Julia Lawall , Netdev , Jiri Pirko To: Joe Perches Return-path: Received: from szxga01-in.huawei.com ([119.145.14.64]:63778 "EHLO szxga01-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751031AbaCCGG4 (ORCPT ); Mon, 3 Mar 2014 01:06:56 -0500 In-Reply-To: <1393821407.13719.65.camel@joe-AO722> Sender: netdev-owner@vger.kernel.org List-ID: On 2014/3/3 12:36, Joe Perches wrote: > (adding Jiri Pirko to cc's) > > On Mon, 2014-03-03 at 10:49 +0800, Ding Tianhong wrote: >> On 2014/3/3 9:49, Joe Perches wrote: >>> On Mon, 2014-03-03 at 09:14 +0800, Ding Tianhong wrote: >>>> Ether_addr_equal_64bits is more efficient than ether_addr_equal, and >>>> can be used when each argument is an array within a structure that >>>> contains at least two bytes of data beyond the array, so it is safe >>>> to use it for vlan. >>> [] >>>> diff --git a/net/8021q/vlan_core.c b/net/8021q/vlan_core.c >>> [] >>>> @@ -26,7 +26,7 @@ bool vlan_do_receive(struct sk_buff **skbp) >>>> /* Our lower layer thinks this is not local, let's make sure. >>>> * This allows the VLAN to have a different MAC than the >>>> * underlying device, and still route correctly. */ >>>> - if (ether_addr_equal(eth_hdr(skb)->h_dest, vlan_dev->dev_addr)) >>>> + if (ether_addr_equal_64bits(eth_hdr(skb)->h_dest, vlan_dev->dev_addr)) >>>> skb->pkt_type = PACKET_HOST; >>>> } >>> >>> Hi again Ding >>> >>> If you do have performance numbers: >>> >>> The lines above this ether_addr_equal_64 are: >>> >>> if (skb->pkt_type == PACKET_OTHERHOST) { >>> /* Our lower layer thinks this is not local, let's make sure. >>> * This allows the VLAN to have a different MAC than the >>> * underlying device, and still route correctly. */ >>> if (ether_addr_equal(eth_hdr(skb)->h_dest, vlan_dev->dev_addr)) >>> skb->pkt_type = PACKET_HOST; >>> } >>> >>> Maybe it'd be faster overall to add an unlikely >>> to the == test >>> >>> if (unlikely(skb->pkt_type == PACKET_OTHERHOST)) { >> >> Sorry, I can't understand it clearly, do you mean that if the skb deliver to the vlan dev, >> it is impossible that the pkt_type is PACKET_OTHERHOST at most time? > > No, just that it's maybe better to add an unlikely > to the test. > > Jiri Pirko's commit 0b5c9db1b modified the code > from a switch/case to a specific test. > > I don't know how likely it is in normal uses for > a packet to be delivered as PACKET_OTHERHOST. > > I just hoped that if you in fact had performance > numbers for your suggested ether_addr_equal_64bits > test, you might be able to run those same tests > with if (unlikely(skb->pkt_type == PACKET_OTHERHOST)) > and see if that was better or worse for performance. > > cheers, Joe > OK, I got it and I will review the commit 0b5c9db1b, try to see the performance. Regards Ding > > -- > To unsubscribe from this list: send the line "unsubscribe netdev" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > >