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Hotplug CPUs for i386 2.5.44

PATCH In review Rusty Russell 3 participants 3 messages Oct 28, 2002 – Nov 8, 2002

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#0 lore raw

PATCH 1/1 Hotplug CPUs for i386 2.5.44

Doesn't apply to -mm5 because someone did wierd things with the CPU placement in driverfs, which clashes with this patch which moves it to kernel/cpu.c...

Usage:
1) Apply patch, and boot resulting kernel.
2) echo 0 > /devices/root/sys/cpu0/online
3) echo 1 > /devices/root/sys/cpu0/online

The CPU actually spins with interrupts off, doing cpu_relax() and polling a variable. It's basically useful for testing the unplug infrastructure and benchmarking.

http://www.kernel.org/pub/linux/kernel/people/rusty/patches/hotcpu-x86-28-10-2002.2.5.44.diff.gz

Cheers!
Rusty.
--
Anyone who quotes me in their sig is an idiot. -- Rusty Russell.

#1 lore raw
Quoted 8 lines · Rusty Russell

Doesn't apply to -mm5 because someone did wierd things with the CPU placement in driverfs, which clashes with this patch which moves it to kernel/cpu.c...

Usage:
1) Apply patch, and boot resulting kernel.
2) echo 0 > /devices/root/sys/cpu0/online
3) echo 1 > /devices/root/sys/cpu0/online

<grins sheepishly>

Errr.. you may want to use /devices/class/cpu/devices/[0..num_online_cpus()]. There are symlinks here for every registered CPU device, no matter how some NUMA wacko rearranges the root/sys directory topology. ;)

Cheers!

-Matt

Quoted 16 lines

The CPU actually spins with interrupts off, doing cpu_relax() and polling a variable. It's basically useful for testing the unplug infrastructure and benchmarking.

http://www.kernel.org/pub/linux/kernel/people/rusty/patches/hotcpu-x86-28-10-2002.2.5.44.diff.gz

Cheers!
Rusty.
--
Anyone who quotes me in their sig is an idiot. -- Rusty Russell.
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#2 lore raw
In reply to Rusty Russell

Hi!

Quoted 8 lines

Usage:
1) Apply patch, and boot resulting kernel.
2) echo 0 > /devices/root/sys/cpu0/online
3) echo 1 > /devices/root/sys/cpu0/online

The CPU actually spins with interrupts off, doing cpu_relax() and polling a variable. It's basically useful for testing the unplug infrastructure and benchmarking.

Hehe, with this swsusp should be doable on an smp machine (turn it into UP and suspend; during resume, turn it into UP, resume, and go back SMP). I guess I schould get some SMP to play with...
Pavel