Re: Can't reach the Gigabit barrier

[Judd Tracy <jtracy@ist.ucf.edu>]

Well ya, because netperf did not involve any other pci bandwidth on the 
motherboard.  As soon as you start using the hard drive for a networked 
files system you start too loose more then half the peak bandwidth you 
got with netperf because now you have pci contention to deal with along 
with symmetrical use of the pci bandwidth by the nic and drive.  But it 
is still a huge improvement over the ~10MB/s you probably were getting 
on 100Tx..  Also 120MB/s peak is very good under linux for such a slow 
system.  Most of the issuses with getting full bandwidth gigabit deal 
with the tcp processing overhead.

Judd

Piszcz, Justin wrote:

> It depends what he's doing.
>
> There is netperf, is it?  It consists of a client/daemon processes; I
> was able to push 90-120MB/s to a Pentium 3 500 MHz box with the same
> board.
>
> However, FTP/NFS were limited to 33MB/s or so to/from this slow machine.
>
> -----Original Message-----
> From: Judd Tracy [mailto:jtracy@ist.ucf.edu] 
> Sent: Thursday, April 14, 2005 1:36 PM
> To: Roberto C. Sanchez
> Cc: SmartList
> Subject: Re: Can't reach the Gigabit barrier
>
> You also have to remember that you only have 32bit pci, so you will 
> never acheive anything close to full speed with your current
> motherboard.
>
> Judd Tracy
>
> Roberto C. Sanchez wrote:
>
>  
>
> > Steve Ramage wrote:
> >
> >    
> >
> > > I have a small server at the specs are as follows
> > >
> > > Duron 900
> > > Gigabyte GA-7ZM
> > > 512 MB PC133 SDRAM
> > > 1x 120 GB HDD
> > > 1x 200 GB HDD
> > > Two networks cards:
> > > 1x D-Link DE-528TX (10 Mbps)
> > > 1x Intel Pro/1000 MT Desktop Adapter (1000 Mbps)
> > > I just added the Intel Pro/1000 adapter, as a replacement to an older
> > > D-Link DFE-538TX ( 100 Mbps)
> > >      
> > <SNIP>
> >
> >    
> >
> > > If I run: ping -f -s 60000 172.27.2.27 from the three machines and
> > > target my Windows machine, the other machine with a 1 Gbps card, I
> > >      
> can
>  
>
> > > get about 45%, usage out of the network, according to windows, so the
> > >      
> > <SNIP>
> >
> > Have you considered that with a low end 900 MHz and slow FSB (133 MHz)
> > that you are going to have a hard time filling a Gigabit pipe?  Think
> > about it.  Gigabit represents ~125 MB/s.  I have a similar low-spec
> > machine and have a hard time getting more than ~70 MB/s across the PCI
> > bus.
> >
> > -Roberto
> >
> > --
> > Roberto C. Sanchez
> > http://familiasanchez.net/~sanchezr
> >    
>
>
>