From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ben Greear Subject: Re: Poor gige performance with 2.4.20-pre* Date: Sun, 29 Sep 2002 12:32:38 -0700 Sender: netdev-bounce@oss.sgi.com Message-ID: <3D975556.5070706@candelatech.com> References: <200209282257.g8SMvta32527@vindaloo.ras.ucalgary.ca> <3D966656.7040205@candelatech.com> <200209291922.g8TJMA312403@vindaloo.ras.ucalgary.ca> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Cc: netdev@oss.sgi.com Return-path: To: Richard Gooch Errors-to: netdev-bounce@oss.sgi.com List-Id: netdev.vger.kernel.org Richard Gooch wrote: > Ben Greear writes: > >>Richard Gooch wrote: >> >>> Hi, all. For a while now I've noticed poor performance with gige >>>cards under 2.4.19 and 2.4.20-pre*. At first I thought it was because >>>of the cheap-ass Addtron cards I bought (these use the ns83820 chip). >>>But now that the Intel E1000 cards are pretty cheap too, I've grabbed >>>a couple (part number: PWLA8390MT) and see the same problem. In fact, >>>the E1000 cards are no better than the Addtron cards. I'm using the >>>D-Link DGS-1008T 8-port gige switch. MTU=1500 bytes. >> >>Try setting the TxDescriptors=4096 RxDescriptors=1024 when loading the >>e1000 module, that helps tremendously when using smaller packets. > > > Didn't help at all. Just to summarise, I've got: > options e1000 TxDescriptors=4096 RxDescriptors=1024 > net.ipv4.tcp_rmem = 262144 262144 262144 > net.ipv4.tcp_wmem = 262144 262144 262144 > MTU=1500 > > I'm doing read(2)/write(2) to/from a user-space buffer over a TCP > socket with 256 KiB buffer size. > > Is the E1000 supposed to have hardware interrupt mitigation (thus > avoiding the need for NAPI)? NAPI did not greatly improve the performance I saw with larger packets, but it did help with smaller (say, 60 byte) packets. One other thing I saw with TCP connections: They started off slow, but after a few seconds they were reacing their peak throughput. How long are you running your test? Ben > > Regards, > > Richard.... > Permanent: rgooch@atnf.csiro.au > Current: rgooch@ras.ucalgary.ca > -- Ben Greear President of Candela Technologies Inc http://www.candelatech.com ScryMUD: http://scry.wanfear.com http://scry.wanfear.com/~greear