Re: 2.4 and 2.5 Problem ne.c driver

[Vojtech Pavlik]

On Sun, Aug 25, 2002 at 07:58:32PM +0200, Christophe Devalquenaire wrote:

> Donald Becker wrote:
> > 
> > On Sun, 25 Aug 2002, Christophe Devalquenaire wrote:
> > > kris wrote:
> > > > kris wrote:
> > > > >
> > > > > I have 2 ne2000 isa cards (10Mbps for each) and with this versions of
> > > > > kernel the bandwith is divided by 2. So 2*5Mbps = 10Mbps instead of
> > > > > 2*10Mbps=20Mbps.
> > > > > I try to fix the pbm.
> > > >
> > > > perhaps a bug exists on the dispatcher when 2 identical cards exist.
> > > > Anyone have 2 identical cards for test ?
> > >
> > > After other tries, the ne.c file is buggy. Confirmation.
> > > I investigate. Anyone helps me ?
> > 
> > Do you have evidence of a specific problem?
> > Or the same hardware running faster with other drivers or kernel versions?
> > 
> > This sounds as if you are just running out of ISA bus bandwidth...
> 
> My configuration : a server with 2 cards NE2000(10 Mbps), a machine with
> 2 cards : 1 NE2000(ISA) and 1 3C905b(PCI).
> server : NE2000 <-> workstation : NE2000  in 192.168.1.X
> server : NE2000 <-> workstation : 3C905b  in 192.168.0.X
> 
> I try with a 2.4.6, 2.4.15, and 2.5.31. there is near from no
> differences in the code of ne.c, gkrellm tells me that when I download
> on both cards big files (for tests), the bandwidth falls to 5Mbps for
> each card.
> If 1 download stops, the other bandwidth is up to 10Mbps immediatly.
> 
> No other ISA card is used on the server.

ISA has a maximum bandwidth usually about a megabyte per second in PIO
(io-port, which the NE2k uses) mode. That's 10MBps. With two cards, i
gets evenly distributed. What's so surprising here?

-- 
Vojtech Pavlik
SuSE Labs