Symmetric/asymmetric multiprocessing

[Bazango]

In some old postings here, there was some discussion about using multiprocessors with Linux. The content of the discussion left me convinced that Linux actually handled multiprocessing even beyond what WinNT could do.

However all of the published references on Linux (Que, Sams, etc.) make no reference to multiprocessing. They all do make references to multitasking, though. I talked to a casual but reliable source for computing and he said that Linux does NOT handle multiprocessing.

Can anyone explain further what is going on? Is there something I am missing that does not show in the index of the published manuals? A cited reference on the subject might clear this up once and for all for me.

[a Bill]

Linux does SMP. I have it in a dual P133 box and Linux uses both CPUs. I seem to recall it can only use up to four CPUs at once but that might be old news. It all depends on the program you run. If the program is set up for multiple CPUs, it gets them. Linux still passes on some overhead to the idle CPU if the program doesn't use it. The RC5 program uses multiple CPUs if you want to take a look at "top" and see what your CPUs are doing.

This URL has some of the more common uses for SMP.

http://www.linux.org/projects/scientific.html

[CMonster]

I just finished reading that the 2.2 kernel is fully SMP capable (Caldera's OL2.2 manual pg160), and I think I remember reading somewhere that the new kernel supports up to 16 processors.

[Bazango]

Well, I'm convinced. The Que special edition manual has a chapter about Multiple Processes, I guess that must be where this faculty is managed. And there is also the distinction of multiprocessors using shared memory.

I have this recuring fantasy about setting up two or three machines old 486s to speed up regular desktop operations along with my own multiprocessor machine.

[CMonster]

That sounds like a great project. About a year ago I read where one of the universities here in SO CAL had linked up about 100 PCs and created a crude super computer using Linux OS

[This message has been edited by CMonster (edited 06-18-99).]

[Zacko10000]

You will have to tell me how that goes, I've also got a bunch of 486s, hmm...maybe I have found a use for them. How would one go about setting this up, do you just network them and set some perameters so they will go into a multi-processing mode?

[a Bill]

All that info can be found at the link I posted earlier.