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
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