From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ben Greear Subject: Re: packet re-ordering on SMP machines. Date: Sun, 25 Aug 2002 21:34:47 -0700 Sender: netdev-bounce@oss.sgi.com Message-ID: <3D69AFE7.6020902@candelatech.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 8bit Cc: netdev@oss.sgi.com Return-path: To: jamal Errors-to: netdev-bounce@oss.sgi.com List-Id: netdev.vger.kernel.org jamal wrote: > That doesnt sound impressive at all. I know it's about .8 of wire rate > but you should be able to exceed that. > Robert was generating in the range of 800Kpps with that NIC if i recall > corectly I had only tested 1514 byte pkts, so I was getting around 880Mbps, which is pretty good as far as I know. I see about 255 kpps when sending 64 byte pkts to myself. Still dropping about 1 in 4000 packets at this speed. I think most of Robert's tests didn't involve actually doing something with the received packet though, and I am inspecting it for latency, sequence number, etc. I'm even doing a __get_timeofday() call to calculate the latency...need to find a faster way to do that... If I only allocate/scan 1 per 100 packets (ie alloc one packet and send it 100 times), then I get a more respectable 365kpps. Robert's patch should definately help! > Also if you have SMP, tie each onto a CPU. That's with the irq_afinity thing in proc, right? > Additionaly get the skb recycler patch from Robert, it should improve > things even more. Do you happen to have a URL for this? Actually, the various network tweaks are relatively hard to find (at least to find the most up-to-date coppies). It would be great if there was a place where they were all concentrated. > > >>Also, I see the hard_start_xmit call failing 5876 times out of 2719493 >>calls (for example). The code that calls the method looks like this: >> > > > I dont have access to that NIC. But a stoopid question: Have you tried > increasing the transmit queue via ifconfig? 1000 packets is reasonable > for gige. I upped it, but it didn't stop the errors. The NIC is still performing, so it may not be a real problem... Thanks for the info, Ben -- Ben Greear President of Candela Technologies Inc http://www.candelatech.com ScryMUD: http://scry.wanfear.com http://scry.wanfear.com/~greear