Subject: Re: Strange behavior with -j 4
To: Manuel Bouyer <>
From: Joseph Sarkes <>
List: current-users
Date: 10/28/2002 21:10:49
I saw this on my macppc  dual G4. I also saw a weird problem doing a
mkisofs where the completion times were jumping back and forth, as if
the two cpus had different times. Is this a possible cause?

On Monday, October 28, 2002, at 01:59 PM, Manuel Bouyer wrote:

> 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 <>
> --