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Date: Wed, 20 Dec 2006 08:16:55 -0600
From: Nathan Lynch <ntl@pobox.com>
To: Giuliano Pochini <pochini@shiny.it>
Subject: Re: 2 CPUs, but only one is used
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Giuliano Pochini wrote:
> On Sun, 17 Dec 2006 14:41:27 +0100
> Giuliano Pochini <pochini@shiny.it> wrote:
> 
> > I have a dual G4 MDD mac running linux 2.6.19. When I boot with maxcpus=1 and
> > then I issue "echo 1 >/sys/devices/system/cpu/cpu1/online" the second CPU is
> > put online without errors, but it stays idle+wait=100% and of course
> > user+system+nice=0%. It works fine without maxcpus=1. No problems with 2.6.18.
> >
> > I saw that there are some cpu hotplug related changes in 2.6.19, but I have
> > no access to a non-ppc dual cpu box to check if the problem also affects
> > other architectures right now.
> 
> I tried to reproduce the problem on an intel box, but I couldn't. /sys
> contains only the cpu0 file if it boots with maxcpus=1.

Can you try to git bisect to find the change which caused the
regression?