This is not strictly true.
In an SMP environment the "other" processor is always available to handle
normal chores.
Since the Kernel rapidly switches tasks to whichever processor is more
lightly loaded even doing minor things such as word processing is much
quicker.
For instance, one processor may handle basic X functions while another the
KDE menu system. One processor bitblts the display while the other fetches
the fonts from the font server, etc.
A single thread will not run any faster... (I.E. Setiathome runs ALMOST as
fast on a totally unloaded single processor system as it does on an SMP
system running X-windows and other processes.) ... in practice the single
thread has more cpu cycles available for it, hence it completes more
quickly.
TWO Setiathome tasks on DUAL SMP take just as long (or faster) as one
setiathome task on an single processor system. (this assumes nothing else is
running, minimal daemons, etc. on the single processor system...).
In the work unit benchmarks two setiathome tasks run faster on SMP than a
single task on a single processor system, effectively shooting down your
assertion.
The reason?
In an SMP environment running background things such as daemons, etc. can be
split across the individual CPUs.
I.E Quake runs MUCH faster in an SMP environment, simply because the other
processor can handle screen IO, etc.
GIMP is almost twice as fast processing script-fu's etc.
An individual filter is no faster however...
Two 850's are far cheaper than a 1.6 gig processor (which is not available
yet) so there is an apparent cost saving over getting a more powerful system
as well.
-JMS
-----Original Message-----
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED]]On Behalf Of Tom Brinkman
Sent: Thursday, January 11, 2001 8:44 AM
To: [EMAIL PROTECTED]
Subject: Re: [newbie] Dual processors ??
On Wednesday 10 January 2001 02:48 pm, abe wrote:
> if you are running an SMP mandrake system will recompiling the
> software you use help it to use the SMP capabilities of the machine
> or not?
No, the software has to be written by the developer(s) to take
advantage of SMP. I believe a Google on 'SMP' will shed more light on
the subject than I ever could. I've only looked into it enough to form
the opinion that it's a waste on a user-desktop system, there's very
little mainstream software that uses SMP. In situations where it could
be useful, the $$'s are prob'ly better spent building a better single
proccessor system .... and if you really need SMP, then you prob'ly
ought'a be lookin into clustering also. YMMV ;)
--
Tom Brinkman [EMAIL PROTECTED] Galveston Bay
>
> You all have me curious now. My girlfriend wants a dual T-Bird
> system for her birthday this summer. This will be a strictly
> mandrake machine.
>
>
> Abe
>
> Tom Brinkman wrote:
> > On Tuesday 09 January 2001 08:17 pm, Mark Weaver wrote:
> > > I'd be real interested in knowing about this too cause I've been
> > > toying with the same idea of building a dual processor system.
> > > Linux is all I run anymore. I'd be more concerned as to how the
> > > kernel would react to such a situation more then some of the apps
> > > on that system. I can't imagine how'd they'd really care whether
> > > there were 1 or 10 processor.
> >
> > Well, i've never run SMP. From what I understand, a multi
> > processor system has no problems running software written for
> > single proccessor systems, but multi cpu systems won't run 'em any
> > faster/better either. The application has to be specifically
> > written and compiled to take advantage of multi proccessors ...
> > and they're few and far between on most all desktop systems.
> > --
> > Tom Brinkman [EMAIL PROTECTED] Galveston Bay
