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Re: 604e's suck (was Yaboot Config Question)

I'm afraid it's even worse than that.  I haven't looked up the
design specs on the web or anything, but I believe the Daystar
design is quite poor in a number of ways, some of them not really in
their control.  First, it's not SMP, it's really AMP, or Asymetric
MP: only processor 0 gets interrupts.  The processor affinity
algorithms in the 2.2 kernel, lame as they are, cause poor
performance on this kind of MP architecture.  I wouldn't be
surprised if 2.0 kernels, which had almost no processor affinity
code, would show better scaling on these systems.  Secondly, only
one processor at a time may use the bus off the daughter card, and
are multiplexed by bus transaction, not by bus cycle.  L2 cache
thrashing is a definite possibility.  But the worst part is that the
604e is but a very pale shadow of the 604, with it's half wide data
and address busses and basically non-existent L1 caches.  It's
specmark numbers for a 200 are below those of a 200MHz PentiumPro. 
So, yes, your 650 Athlon, what with 133 or 200MHz memory bandwidth,
would spank that snot out of a 4 way 604e @ 150MHz.

With almost no disk accesses, my dual 200MHz 604e compiles a certain
kernel config achieving only about a 50% scaling, which is down
right pitiful, but better than nothing!  My dual SparcStation20 and
my dual celeron system achieve greater than 95% scaling on the same
kind of [fairly silly] test.  Such is life.


Peter Cordes wrote:
> On Fri, Apr 06, 2001 at 09:41:50AM -0400, Matthew Grant wrote:
> > I am trying to get Debian 2.2 on a 9600/200MP.
> > When I reboot I get the Disk with the X in it. Which means I
> > need to configure My boot loader. I can't get into OF I get a
> > black screen.
> >
> > I boot with the floppies and go to a shell I mount my root
> > partion (/dev/sda3) to /target and run ybin -b /dev/sda3.
> > It tells me there's no config file. or it tells me it's not a
> > HFS file system.
> >
> > I am used to Lilo and debian on i386. would some one give me a
> > clue on what steps I am suppose to do to configure yaboot.
> > If I am doing this ass backwards send me a Link to were I can
> > learn the PowerPC way.
>  Problem number one: the 9600 is an oldworld machine.  You can't use yaboot.
> If you're planning to dual boot, then use bootx.  Otherwise, use bootx for
> now, until you figure out quik.  (I've had good luck with BootX on my
> Daystar Genesis MP, which is similar to your system I guess.  BTW, I've
> found that compiling kernels isn't nearly as fast as I hoped it would be
> with 4 PPC604 CPUs at 150MHz.  I think the problem is that they share the L2
> cache, and it isn't big enough to keep 4 gcc processes happy.  That, and the
> limited memory bandwidth/latency bring it down.  My Athlon 650 is about 5
> times faster at compiling.  Both machines have 128MB of RAM.  The pmac has
> old (but decent) SCSI disks.)
> --
> #define X(x,y) x##y
> Peter Cordes ;  e-mail: X(peter@llama.nslug. , ns.ca)
> "The gods confound the man who first found out how to distinguish the hours!
>  Confound him, too, who in this place set up a sundial, to cut and hack
>  my day so wretchedly into small pieces!" -- Plautus, 200 BCE
> --
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