SMP and dual tulip: Solution!

Brian Macy
Wed Nov 10 12:02:28 1999

Yep, unfortunately reality vs theory :) Do me a favor... do hdparm -Tt
/dev/?da and send me the results with MPS 1.1 and 1.4. Please include
your BIOS rev too. I don't think this has anything to do with multiple
CPUs, just a bug in the MPS 1.4 implementation.

Brian Macy

"M.Brands" wrote:
> On Tue, Nov 09, 1999 at 03:41:04PM -0800, Brian Macy allegedly wrote:
> > Note that this is likely a bad "solution". Your memory bandwidth is
> > likely halved... don't know why, it just happens.
> >
> > Brian Macy
> Erm, hmm, it shouldn't. I must admit I haven't done any test with
> regard to memory bandwidth, but I'll check. The memory bandwitdh
> you measure should be the same with both one and two cpu's (pretty
> obvious). It probably reaches it's peak at 300-400 MB/sec (if it
> even gets that high). The MPS version used shouldn't have any
> effect on the memorybandwith. Memorybandwith on Intel based systems
> is crappy anyway. I guess a crossbar-switch like the ones used in
> the more high-end Sun, DEC and SGI boxes is probably too expensive.
> I do wonder what kind of solution they've come up with for four and
> eight CPU Xeon boards - 400 MB/sec is just no enough for eight CPU's.
> They've probably dug up multiplexing of memorybanks again :)
> Oh well,
> Mathijs