Re: [RFC] The meaning of local_cpulist and local_cpus

From: Bian LuLu
Date: Thu Apr 25 2013 - 09:58:14 EST


Thankyou .
But I still can not understand what is the meaning of cuplist.
my linux version is ubuntu 12.04, and
my system:/$ cat /sys/devices/pci0000:00/0000:00:1a.0/local_cpulist
the result is '0-7',

I just don't konw what are they represent .Could you give me more
detailed information about local_cpulist and local_cpus,and their
relations.
thanks in advance :)

On Thu, Apr 25, 2013 at 12:56 AM, Mike Travis <travis@xxxxxxx> wrote:
>
>
> 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 <helianthus.lu@xxxxxxxxx> 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 http://lxr.linux.no/linux+v3.5.4/drivers/pci/pci-sysfs.c#L390 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.
I can not understand the symbol of '#' ,what is the meaning of it?
> Here's the difference on a system that has 1024 cpu threads:
>
> harp31-sys:/sys/devices/system/node/node20 # cat cpulist
> 160-167,672-679
> harp31-sys:/sys/devices/system/node/node20 # cat cpumap
> 00000000,00000000,00000000,00000000,00000000,00000000,00000000,
> 00000000,00000000,00000000,000000ff,00000000,00000000,00000000,
> 00000000,00000000,00000000,00000000,00000000,00000000,00000000,
> 00000000,00000000,00000000,00000000,00000000,000000ff,00000000,
> 00000000,00000000,00000000,00000000
>
> Which is easier to interpret? :)
>
> But there are some older user side utilities that still
> use the mask format.
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