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SubjectRe[2]: NE2000 slow interrupts safe?
>     insw(NE_BASE + NE_DATAPORT,buf,count>>1);
>
> I don't call that polling! What bothers me is that my colleague is
> reporting under 140 microseconds for his pSOS ISR, now that he's coded
> some of it in assembler and increased the ISA clock to 12 or 16
> MHz. And this is on a 486 DX2-66! I would expect that my PCI card with
> a PPro would be able to match that, but apparently not.
> This is something I'd like to track down.

Assuming the insw macro is generating the same rep ins instructions
that his pSOS driver is using then I'd say its just a case that your
PCI ne2000 is a piece of junk, or your motherboard chipset is. From
personal experience I have seen a 16MHZ 386 outperform a DX4/100 in
terms of ISA DMA using the same driver and card, which shows that
the chipset can be more important than the processor speed. Also
your card may be forcing I/O wait states or doing any number of awful
things. Bottom line is the length of time a "rep ins" takes is pure
hardware and a fast cpu on PCI bus is only one link in the chain.

Time to get the logic analyzer out and have some *real* fun checking that
transfer :). BTW, Have you timed a tulip card?


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