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

[Damien Millescamps <damien.millescamps@6wind.com>]

On 05/31/2013 05:45 PM, Stephen Hemminger wrote:
> This was confirmed by several kernel developers including Andi Kleen from
> Intel. The value in /proc/cpuinfo comes from the APCI tables and is the value
> reported by the BIOS. There are machines that report socket 1 and 2.
> Haven't played with older kernels, but the topology information in sysfs
> has existed since 2.6.16.
Hi Stephen,

You didn't really address my point, because the Linux documentation says
something doesn't mean it works in the real world.

If you take the example of the hugepages, they have been in the Linux
kernel since 2.6.28, but the last fix was pushed in 2.6.37 and before
2.6.33 it is just impossible to do something with hugepages.
If you take a look at section 2.3.2 of the DPDK getting started:
http://www.intel.com/content/dam/www/public/us/en/documents/guides/intel-dpdk-getting-started-guide.pdf,
you will find that this issue is at least partially addressed.

So the point is that the topology information being theoretically
correct on all kernel Linux supported by the DPDK, but the information
being practically wrong on versions prior to kernel 3.3 means that the
"fix" is breaking the support for a quite huge range of kernel versions...
So maybe there might be a better way to get this node information on all
kernel still currently supported by the DPDK.

Cheers,
-- 
Damien Millescamps