lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
Open Source and information security mailing list archives
| ||
|
Date: Thu, 05 Mar 2009 10:40:27 +0800 From: "Zhang, Yanmin" <yanmin_zhang@...ux.intel.com> To: David Miller <davem@...emloft.net> Cc: herbert@...dor.apana.org.au, netdev@...r.kernel.org, linux-kernel@...r.kernel.org, jesse.brandeburg@...el.com, shemminger@...tta.com Subject: Re: [RFC v1] hand off skb list to other cpu to submit to upper layer On Thu, 2009-03-05 at 09:04 +0800, Zhang, Yanmin wrote: > On Wed, 2009-03-04 at 01:39 -0800, David Miller wrote: > > From: "Zhang, Yanmin" <yanmin_zhang@...ux.intel.com> > > Date: Wed, 04 Mar 2009 17:27:48 +0800 > > > > > Both the new skb_record_rx_queue and current kernel have an > > > assumption on multi-queue. The assumption is it's best to send out > > > packets from the TX of the same number of queue like the one of RX > > > if the receved packets are related to the out packets. Or more > > > direct speaking is we need send packets on the same cpu on which we > > > receive them. The start point is that could reduce skb and data > > > cache miss. > > > > We have to use the same TX queue for all packets for the same > > connection flow (same src/dst IP address and ports) otherwise > > we introduce reordering. > > Herbert brought this up, now I have explicitly brought this up, > > and you cannot ignore this issue. > Thanks. Stephen Hemminger brought it up and explained what reorder > is. I answered in a reply (sorry for not clear) that mostly we need spread > packets among RX/TX in a 1:1 mapping or N:1 mapping. For example, all packets > received from RX 8 will be spreaded to TX 0 always. To make it clearer, I used 1:1 mapping binding when running testing on bensley (4*2 cores) and Nehalem (2*4*2 logical cpu). So there is no reorder issue. I also worked out a new patch on the failover path to just drop packets when qlen is bigger than netdev_max_backlog, so the failover path wouldn't cause reorder. > > > > > > You must not knowingly reorder packets, and using different TX > > queues for packets within the same flow does that. > Thanks for you rexplanation which is really consistent with Stephen's speaking. -- 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
Powered by blists - more mailing lists