From mboxrd@z Thu Jan 1 00:00:00 1970 From: Michael Iatrou Subject: Re: e1000 (?) jumbo frames performance issue Date: Fri, 6 May 2005 00:55:55 +0300 Message-ID: <200505060055.55778.m.iatrou@freemail.gr> References: <200505051928.32496.m.iatrou@freemail.gr> <427A7F5B.8050704@hp.com> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-7" Content-Transfer-Encoding: 7bit Cc: netdev@oss.sgi.com Return-path: To: Rick Jones In-Reply-To: <427A7F5B.8050704@hp.com> Content-Disposition: inline Sender: netdev-bounce@oss.sgi.com Errors-to: netdev-bounce@oss.sgi.com List-Id: netdev.vger.kernel.org When the date was Thursday 05 May 2005 23:17, Rick Jones wrote: > What settings, if any, did you use for -s, -S and in particular -m in > netperf? -s 0 -S 0 -m 16384 For both ends: /proc/sys/net/core/wmem_max: 16777216 /proc/sys/net/core/rmem_max: 16777216 /proc/sys/net/ipv4/tcp_rmem: 16384 349520 16777216 /proc/sys/net/ipv4/tcp_wmem: 16384 262144 16777216 > I seem to recall that some of the stack defaults for SO_SNDBUF (IIRC) would > result in netperf sending 16KB at a time into the connection - once you > sent the MTU above 16K you may have started running into issues with Nagle > and delayed ACK? The problem firstly appears at 12KB... > You could try some tests adding a test-specific -D to > disable Nagle, or -C to set TCP_CORK, or use -m to set the send size to > say, 32KB. I 've already tested -m 32KB and its the same as 16KB. I will try -D and -C too. > It might be good to add CPU utilization figures - for 2.3pl1 that means > editing the makefile to add a -DUSE_PROC_STAT and recompiling. Or you can > grab netperf 2.4.0-rc3 from: > > ftp://ftp.cup.hp.com/dist/networking/benchmarks/netperf/experimental/ > > if you cannot find it elsewhere, and that will (try to) compile-in the > right CPU utilization mechanism automagically. I already did a custom CPU usage instrumentation (based on infos from /proc/stat -- the latest netperf does the same thing, doesn't it?) and it seems that system has plenty of idle time (up to 50% if I recall correct) -- Michael Iatrou Electrical and Computer Engineering Dept. University of Patras, Greece