[svlug] Dual cpu

[Justin Ryan]

I think www.gcc.ml.org has info on PGCC, PEntium-optimized EGCS-based
compiler

|--------------------------------------------------
|Justin Ryan
|Developer Relations / Support Associate
|Pacific HiTech / TurboLinux
|http://www.turbolinux.com / justin at turbolinux.com
|WebMaster, PCHelp - http://computers.iwz.com
|justin at computers.iwz.com
|--------------------------------------------------

On Sun, 28 Feb 1999, Javilk wrote:

> > In other words, the kernel plays a large role but how the applications
> > themselves are written plays an equally large role. Threading with things
> > like pthreads allows apps to take greater advantage of multiprocessors. An
> > straight-line coded application might get NO performance advantage in a
> > multiprocessor environment if it is the only application running on the
> > machine.
> 
>      Having briefly worked with a 128 processor supercomputer, I have seen
> this to be true.  A badly written application can actually take longer on
> a multi-processor machine due to cache flushing and synchronization
> overhead. (The machines I worked with had bar graph displays showing what
> portion was OS-Overhead, User program, and Idle.  Hit it with a bad app,
> and the bars go red with OS-Overhead!) But when different tasks are
> running, or when well written applications are run, WoW! Are they FAST!!!
> 
>      Since UNIX in general runs multiple tasks, and since we often have
> several applications running at the same time; there is considerable
> performance improvement that can be had from the use of multi-CPU
> computers. Indeed, the use of multiple redundant processor segments is
> supposed to be the strategy for performance improvement of the Pentium
> chip over the 486 chip. To what degree this is exploited (or exploitable)
> on an OS level on the Pentium architecture, is not clear to me.  However,
> when the Pentium was introduced, it was said that improvements in
> performance required re-compilation of code with a Pentium optimized
> compiler..
> 
>      Does anyone know more about this?
> 
> - javilk at mall-net.com -----------------------------
> -------- MS asks "Where do you want to go?" -------
> ------- Linux asks "What do you want to do?" ------
> -- It is doers, not goers, who built this world! --
> --------- Member: http://www.svlug.org/ -----------
> 
>