Re: 3 ways to represent cpu affinity in /sys and counting

[Jesse Barnes <jbarnes@sgi.com>]

On Saturday, December 25, 2004 4:27 pm, Anton Blanchard wrote:
> Hi,
>
> We have a patch to change pcibus_to_cpumask to pcibus_to_node. This makes
> it more consistent with cpu_to_node, and when you want a cpumask you
> use node_to_cpumask.

Great!  I think Matt Dobson said he was going to do something similar, but he 
got sidetracked (and iirc, ak also didn't like the idea).  FWIW, I like it, 
with the caveat that the node returned from pcibus_to_node may not have any 
memory or CPUs associated with it.

> A pci device has a local_cpus property:
>
> /sys/devices/pci000a:00/000a:00:02.6/local_cpus
>
> A pci_bus has a cpuaffinity property:
>
> /sys/class/pci_bus/000d:d8/cpuaffinity

I don't know how these two got different names...

> A node has a cpumap property:
>
> /sys/devices/system/node/node3/cpumap
>
> Can we standardize on a single property name for this? :)

Seems like nodes should have a cpumap and PCI busses should have a node.

> Furthermore, looking at node linkages:
>
> A node has symlinks to cpus:
>
> /sys/devices/system/node/node0/cpu0 -> /sys/devices/system/cpu/cpu0
>
> But doesnt have symlinks to pci devices.

Yep, this would be nice to have.

Jesse