Have a look on that URL : Mirror http://www.irisa.fr/prive/dmentre/smp-faq/smp-faq.html or http://www.phy.duke.edu/brahma/smp-faq/ -----Message d'origine----- De: Darin [mailto:[EMAIL PROTECTED]] Date: vendredi 17 septembre 1999 15:38 �: [EMAIL PROTECTED] Objet: Re: [expert] SMP newbie On Fri, 17 Sep 1999, you wrote: > Hello all! > > I've taken the plunge and picked up a pair of Celeron 400's and an Abit > BP6 board. This is my first foray into the wild yonders of SMP, so > forgive my naive questions. > > I was under the impression that since the kernel and libc libraries > natively support SMP, applications would automatically make use of both > processors without intervention. I'm wondering whether I was incorrect. > > As a test, I ripped an audio track from a CD and started 'notlame' (also > tested 'bladeenc' with similar results) to encode the wav file. Using > top, the encoding process never used more than 50% of CPU time. This > makes me think that it's only making use of one processor. Even using > 'nice -19 <blah>' never yielded much more than 50% CPU. > > Was I naive to think that applications "auto-magically" benefit from > SMP? Anyone know of an MP3 encoder that will make use of the second > processor? Steve, Were you using Top to see application activity? I think you probably were. When Top shows 50% CPU being used in a dual CPU system, that means that the ripper/encoder were using all of 1 CPU. KPM shows things a little differently. Anyways.. To answer your question. If you want a single application to use both CPUs, it has to be capable of multi-threading. Without that, the program can never use more than 1 CPU at a time. I'm not aware of too many applications that can do that. I know Photoshop when used with NT can use more than 1 CPU. But, there is an advantage.. Take the CD Ripping and Encoding for example. I use Krabber with CD Paranoia and Bladenc. Krabber allows you to start more than 1 encoder at a time. So, I have it start 2. That way, the CD is done ripping in 1/2 the time. Or, I can run Seti@HOME reniced at 20 and still have plenty of horsepower left to do other things so that it gets full use of the other processor. I can also compile apps and still do other things while the app compiles. Darin - -- Cthulhu for President in 2000 - Why settle for the lesser evil????
