SMP newbie

SMP newbie

Post by Rob Lov » Mon, 14 Aug 2000 04:00:00



Hello,
    I have been a Linux user for a few months, and I am going to build a
computer running the SMP kernel. I am in the process of buying my pci cards
and I just started wondering if I am going to run into problems with driver
support under the SMP kernel. For example is a Voodoo 3 3000 pci going to
run on a SMP machine? How about sound cards? Lastly, what happens when I run
programs designed for single processor machines, I assume that the kernel
just schedules that process to one of the processors and there isn't a
problem, but I am really not sure... Any SMP users out there that can help
me out?

Thanks,
    Rob Love.

 
 
 

SMP newbie

Post by D. Stimit » Mon, 14 Aug 2000 04:00:00



> Hello,
>     I have been a Linux user for a few months, and I am going to build a
> computer running the SMP kernel. I am in the process of buying my pci cards
> and I just started wondering if I am going to run into problems with driver
> support under the SMP kernel. For example is a Voodoo 3 3000 pci going to
> run on a SMP machine? How about sound cards? Lastly, what happens when I run
> programs designed for single processor machines, I assume that the kernel
> just schedules that process to one of the processors and there isn't a
> problem, but I am really not sure... Any SMP users out there that can help
> me out?

> Thanks,
>     Rob Love.

SMP won't affect your video card on linux (well, no cases I've heard
of). Some sound card support doesn't behave right in SMP, being choppy.
E.G., some releases of the emu10k1 work fine on sblive, other releases
have problems (it is continually evolving). And you are correct that
programs which are not threaded for SMP work just fine on SMP, they just
don't use both cpu's.

Stay away from SuperMicro i840 chipset boards. Some i840 boards might be
fine, but check on your particular board before purchasing.

 
 
 

SMP newbie

Post by emc.. » Tue, 15 Aug 2000 04:00:00



> Hello,
>     I have been a Linux user for a few months, and I am going to build a
> computer running the SMP kernel.

Frankly, the level of questions you're asking suggests that you should
not build an SMP computer right now.

Quote:> I am in the process of buying my pci cards and I just started
> wondering if I am going to run into problems with driver support
> under the SMP kernel. For example is a Voodoo 3 3000 pci going to
> run on a SMP machine? How about sound cards?

There's a chance they won't, but it's a relatively small chance.  I
had an extremely odd resource conflict caused by my RAID card which
appeared only when I added a second CPU and enabled MPS in Windows
2000.  (Yow... the guys at Tyan tech support were absolutely
flabbergasted, as the first they'd heard of this was when a guy called
last week and told them about it, and suddenly they had _another_ call
about what they'd been convinced was a freak accident.)

Manually setting the IRQ for slot 2 (I have AGP video) to 10 fixed the
problem instantly.  Freak error indeed.  The guy at Adaptec (who came
up with the solution) was even more surprised than the guys at Tyan.

Quote:> Lastly, what happens when I run programs designed for single
> processor machines, I assume that the kernel just schedules that
> process to one of the processors and there isn't a problem, but I am
> really not sure...

If by "programs designed for single processor machines" you mean
"single-tasking" (programs that don't use multiple processes or
threads), then yes, that's exactly what happens.  Even with that, some
CPU activity (interrupts, etc.) will happen on the other processor.

Multithreading or multitasking apps will split the load between CPUs,
whether they were compiled on a single-CPU system or not.

Quote:> Any SMP users out there that can help me out?

Was just inducted into their noble ranks today!

--

"The politics of failure have failed!  We need to make them work again!"
        - Kodos, The Simpsons