Re: [dpdk-dev] [PATCH v5] build: optional NUMA and cpu counts detection

["Juraj Linkeš" <juraj.linkes@pantheon.tech>]

> -----Original Message-----
> From: David Christensen <drc@linux.vnet.ibm.com>
> Sent: Tuesday, August 3, 2021 1:29 AM
> To: Juraj Linkeš <juraj.linkes@pantheon.tech>; thomas@monjalon.net;
> david.marchand@redhat.com; bruce.richardson@intel.com;
> Honnappa.Nagarahalli@arm.com; Ruifeng.Wang@arm.com;
> ferruh.yigit@intel.com; jerinjacobk@gmail.com; jerinj@marvell.com;
> stephen@networkplumber.org; Piotr Kubaj <pkubaj@FreeBSD.org>
> Cc: dev@dpdk.org
> Subject: Re: [PATCH v5] build: optional NUMA and cpu counts detection
> 
> 
> 
> On 8/2/21 5:44 AM, Juraj Linkeš wrote:
> >> +if os.name == 'posix':
> >> +    if os.path.isdir('/sys/devices/system/node'):
> >> +        numa_nodes = glob.glob('/sys/devices/system/node/node*')
> >> +        numa_nodes.sort()
> >> +        print(int(os.path.basename(numa_nodes[-1])[4:]) + 1)
> >> +    else:
> >> +        subprocess.run(['sysctl', '-n', 'vm.ndomains'], check=False)
> >> +
> >
> > Bruce, David, Thomas,
> >
> > Is DPDK actually supported on Power9 FreeBSD? Is anyone using this
> combination? How can we address the open question of what exactly does
> sysctl -n vm.ndomains return on a Power9 FreeBSD system? Or should we just
> leave it as is? Or maybe add 1 to the output (as we do in other cases)?
> 
> Not supported within IBM, but you can buy OpenPOWER boxes from 3rd parties
> such as Raptor Computing Systems so there may be customers using DPDK on
> POWER with FreeBSD that I don't track.  Adding Piotr Kubaj who has commented
> on POWER/FreeBSD issues in this past.
> 
> Dave

Thanks, David.

Piotr, to provide more context, we're trying to figure out what the highest NUMA node on a system is.
On P9 systems, here's how NUMA nodes look like in Linux:
NUMA node0 CPU(s):   0-63
NUMA node8 CPU(s):   64-127
NUMA node252 CPU(s):
NUMA node253 CPU(s):
NUMA node254 CPU(s):
NUMA node255 CPU(s):
The highest NUMA with CPUs is node8.

We're trying to get the highest NUMA with CPUs on P9 FreeBSD systems, but we don't know whether FreeBSD NUMA layout looks the same (does FreeBSD report non-contiguous NUMA nodes as Linxu above, or does it renumerate) a what does "systemctl -n vm.ndomains" return. Could you check these for us?