Re: [RFC] The meaning of local_cpulist and local_cpus

From: Mike Travis
Date: Wed Apr 24 2013 - 12:57:07 EST

On 4/24/2013 9:48 AM, Bjorn Helgaas wrote:
> [+cc linux-pci, Mike]
> On Wed, Apr 24, 2013 at 4:06 AM, Bian LuLu <> wrote:
>> Hi all,
>> Recently, i read some codes of PCI portions. I think
>> local_cpulist is a list about one kind of CPU and
>> local_cpus is a mask of CPU. But i am not sure when
>> and how i should use these two parameters.
>> See for
>> details.
>> Would anyone please give me some suggestions?
>> Thanks in advance ;-)
> I don't know off-hand, but maybe Mike or somebody on linux-pci does.
> It looks like Mike added local_cpulist with 39106dcf85.

It primarily comes into play when you have a large # of cpus.
Here's the difference on a system that has 1024 cpu threads:

harp31-sys:/sys/devices/system/node/node20 # cat cpulist
harp31-sys:/sys/devices/system/node/node20 # cat cpumap

Which is easier to interpret? :)

But there are some older user side utilities that still
use the mask format.
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at
Please read the FAQ at