CPU 1 refused to die!

CPU 1 refused to die!

[Giuliano Pochini]

I booted with maxcpus=1, then I enabled the 2nd cpu
with echo 1 > /sys/devices/system/cpu/cpu1/online

I can't disable it anymore. dmesg says "CPU 1 refused to die!".
/proc/cpuinfo and /proc/interrupts show one cpu only and the tasks run on
one cpu after the echo 0 > /sys/... , but since the command takes a couple
of seconds to complete I think it's not simply a bogus error message.

Dual G4 MDD
Linux Jay 2.6.16.16 #8 SMP Sat May 13 19:15:05 CEST 2006 ppc 7455,
altivec supported PowerMac3,6 GNU/Linux

--
Giuliano.

Re: CPU 1 refused to die!

[Nathan Lynch]

Giuliano Pochini wrote:
> 
> I booted with maxcpus=1, then I enabled the 2nd cpu
> with echo 1 > /sys/devices/system/cpu/cpu1/online

So onlining at runtime seems to work.  Did you verify that tasks get
run on the 2nd cpu after you online it?  Any other strange messages in
dmesg?

> I can't disable it anymore. dmesg says "CPU 1 refused to die!".

But offlining doesn't.

Can you online and offline cpus if you boot without maxcpus=1?

Re: CPU 1 refused to die!

[Giuliano Pochini]

On 23-May-2006 Nathan Lynch wrote:
> Giuliano Pochini wrote:
>>
>> I booted with maxcpus=1, then I enabled the 2nd cpu
>> with echo 1 > /sys/devices/system/cpu/cpu1/online
>
> So onlining at runtime seems to work.  Did you verify that tasks get
> run on the 2nd cpu after you online it?

Yes, I did, and the difference in speed is pretty obvious.


> Any other strange messages in dmesg?

Nothing unusual.


> Can you online and offline cpus if you boot without maxcpus=1?

It behaves exactly the same. I can't say exactly when it stopped
working. 2.6.14 worked fine.


--
Giuliano.

Re: CPU 1 refused to die!

[Giuliano Pochini]

On Thu, 25 May 2006 14:46:19 +0200 (CEST)
Giuliano Pochini <pochini@shiny.it> wrote:

Problem solved with 2.6.17


--
Giuliano.