Newsgroups: comp.parallel,comp.arch
From: bjl@ecf.toronto.edu (LEE  BRIAN)
Subject: SMP bus bandwidth consumption
Organization: University of Toronto, Engineering Computing Facility
Date: 21 Dec 1995 04:25:27 GMT
Message-ID: <DJHnnv.2r8@ecf.toronto.edu>

(Sorry if you've seen this posting before, but I'm suspecting that my
news machine is faulty...  Anyway...)

With regards to a generic shared bus multiprocessor with N processors,
each consuming B of the bus' bandwidth, what is the expected bandwidth
consumption given the "average"* application?  Or, what is the bandwidth
the bus must provide in order to keep "satisfactory" perofmance?

* - the 10% reads, 5% writes snoopy type set up.

I think I recall seeing a rule of thumb something like: 2.5 * B * N
in the literature out there.  Any derivations you have to offer?

Thanks
bjl

-- 
Brian Jonathan Lee (aka "hojo")    | "Beef satay?!?!  Not beef satay again!!!!"
   bjl@ecf.toronto.edu             | "XMen! XMen! Rescue Kitty from the caves!"
   bjl@eecg.toronto.edu            | "Evil thy name is NETREK!"


