[dpdk-dev] [PATCH 0/7] Vyatta patches

[Damien Millescamps]

On 05/30/2013 07:12 PM, Stephen Hemminger wrote:
> One fix not included is the NUMA cpu assignment. The original Intel code
> in 1.2 incorrectly used /proc/cpuinfo to try and assign CPU's to NUMA socket.
> The problem is that /proc/cpuinfo physical_id corresponds to what the BIOS
> tells the kernel and is intended for messages only. For example, on our
> Dell boxes the first CPU and only CPU is reported as physical_id 1!
> The fix is to use sysfs instead,
Hi Stephen,

Are you using the
/sys/devices/system/node/nodeX/cpuX/topology/physical_package_id special
file ?

If so, then it is only usable starting from Kernel 3.3 according to this
fix:
http://git.kernel.org/cgit/linux/kernel/git/tip/tip.git/commit/?id=64be4c1c2428e148de6081af235e2418e6a66dda

The value returned for kernel prior to 3.3 is really not better than the
one from /proc/cpuinfo, so that's kind of a robbing Peter to pay Paul
example...

There is obviously a problem with the NUMA node ID detection right now
since both /proc/cpuinfo and /sys can return incorrect values, however
the node and cpu numbering is always good in the kernel boot log from
what I know. So there might be a better way to find the real node ID
whatever the kernel version used.

Cheers,
-- 
Damien Millescamps