[SCore-users] Slow communication

[JJ]

Shinji,

thanks a lot for your prompt reply. I changed the  value of 
maxnsend to 16 and value of backoff to 2400 and everything works
much better now. However, the performance for small packets is 
still far from the expected one.

For example, here is a part of the table for mpi_bw2:

size (Bytes) Linksys (83820) Tamarack (tc902x)
4		222059		39286
48		2.527e+06	472280
128		6.37e+06	1.28e+06
...
1024		2.80e+07	1.61e+07
...
8192		6.94e+07	4.22e+07
...
98304		9.22e+07	8.76e+07
...
524288		1.03e+08	1.11e+08

The performance of tc902x is better for huge messages, as you can see.
I will read the suggested manual, but do you have any quick hint how
to get even closer to desired performance?


The driver was added as a source to Longshine gigabit card and
it was written by Craig Rich, craig_rich at sundanceti.com. There
is nothing written about the license.

Jure

uoting Shinji Sumimoto <s-sumi at flab.fujitsu.co.jp>:

> Hi.
> 
> Have you tuned some paramters in pm-ethernet.conf?
> 
> Important parameters are maxnsend and backoff.
> If you do not try, could you try it?
> 
> The parameters depend on the NIC hardware.
> The descriptions of the parameters are:
> 
> http://www.pccluster.org/score/dist/score/html/en/man/man5/pm-ether-conf.html
> 
> May be following parameter is that you try first.
> 
> maxnsend 16
> backoff 2400
> 
> PS: I have not seen the linux driver for Tamarack 9021.
>     Where have you gotten the driver?
> 
> Shinji.
> 
> From: Jure <jj at guest.xenya.si>
> Subject: [SCore-users] Slow communication
> Date: Mon, 12 Aug 2002 10:53:41 +0200 (CEST)
> Message-ID: <1029142421.3d57779548a5c at webmail.stimm-mz.si>
> 
> jj> Hello,
> jj> 
> jj> I am experimenting with score on two machines. For communication  I
> first used 
> jj> Linksys gigabit coper cards (nc83820) and everything worked well.
> Then I 
> jj> replaced Linksys cards with longshine fiber gigabit cards. 
> jj> 
> jj> I changed mac addresses in /opt/score/etc/pm-ethernet.conf
> jj> and in /opt/score/etc/ndconf/0 and /opt/score/etc/ndconf/1.
> jj> 
> jj> First I tested the regular mpi communication over tcp and it works
> jj> much better on longshine cards than on linksys.
> jj> 
> jj> However, when I want to run mpitest (rtt, bw, bw2) over pm, the
> jj> communication is very, very slow.
> jj> 
> jj> Is there anything I can do? Did I perhaps forget something in score
> 
> jj> configuration?
> jj> 
> jj> The chipset on longshine card is Tamarack 9021.
> jj> 
> jj> I would very much appreciate any hint.
> jj> 
> jj> Jure
> jj> 
> jj> 
> jj> 
> jj> _______________________________________________
> jj> SCore-users mailing list
> jj> SCore-users at pccluster.org
> jj> http://www.pccluster.org/mailman/listinfo/score-users
> jj> 
> jj> 
> ------
> Shinji Sumimoto, Fujitsu Labs
> 
>