Subject: Re: i386 MP performance ( and generic almost same)
To: Steven M. Bellovin <>
From: Paul Goyette <>
List: current-users
Date: 11/11/2007 06:47:07
On Sun, 11 Nov 2007, Steven M. Bellovin wrote:

> Compilation is indeed CPU-bound; however, unless you've taken special
> steps, it's a single process at a time.  What you need to do is specify
> '-j 2' when invoking, to run two processes simultaneously;
> see /usr/src/BUILDING for details.

In my experience, '-j 2' won't be enough to provide definitive results, 
since that seems to improve performance on uni-processor systems, too 
(though not by as much).  On my AMD X2 systems I run builds with it set 
to '-j 4' and that seems to give the most benefit.

But even on uni-processors '-j 2' will improve things since it gives a 
chance for a second job to run on the (only) CPU while the other one is 
waiting for I/O completion.

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