Subject: Re: Strange behavior with -j 4
To: Julio Merino <>
From: Manuel Bouyer <>
List: current-users
Date: 10/28/2002 19:59:51
On Sun, Oct 27, 2002 at 07:48:38PM +0100, Julio Merino wrote:
> Hello
> My i386 box is single-processor, but I wanted to try a with
> -j 4 to see if performance incremented a bit (like I used to do in
> FreeBSD). Everything went ok until a point where everything started
> to go extremely slow.
> I checked this with the wmcpuload dock applet, which shows how much
> cpu is used in percentage. When the build reached "that" point (I have
> the log, can check it later), I saw the cpu most of the time at 0%,
> and it was going up for few moments... i.e.., it did 0% -> 30% (a
> second) -> 0%. And 0% delayed around 2 - 3 seconds. (replace 30% with
> any other value, as sometimes reached 100%). Just to say than before
> I noticed this behavior, uptime showed a load average around 10 and
> before that point, around 1 or 2...
> So I stopped the build and restarted it without -j 4, and using -u.
> When it reached the same point as before, wmcpuload said always 100%
> cpu load, which I believe. Files are compiled much faster than before.
> Now, it's still compiling, and cpu does not get lower than 90% load...
> Anybody knows what's going on?

I noticed similar problems. For me it happens when building the boot floppies.
I suspect it's a make issue, it seems make waits a very long time (several
seconds) between the end of a subprocess and the start of the next one.

Manuel Bouyer <>