On Thu, Sep 09, 2021 at 07:20:27AM +0000, Juraj Linkeš wrote:

quoted

-----Original Message-----
From: Bruce Richardson <redacted>
Sent: Tuesday, August 31, 2021 10:03 AM
To: Juraj Linkeš <redacted>
Cc: Piotr Kubaj <redacted>; David Christensen
[off-list ref]; thomas@monjalon.net;
david.marchand@redhat.com; Honnappa.Nagarahalli@arm.com;
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jerinj@marvell.com; stephen@networkplumber.org; dev@dpdk.org
Subject: Re: [PATCH v5] build: optional NUMA and cpu counts detection

On Tue, Aug 31, 2021 at 07:54:16AM +0000, Juraj Linkeš wrote:

quoted

quoted

-----Original Message-----
From: Piotr Kubaj <redacted>
Sent: Tuesday, August 31, 2021 2:55 AM
To: Juraj Linkeš <redacted>
Cc: David Christensen <redacted>; 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; dev@dpdk.org
Subject: Re: [PATCH v5] build: optional NUMA and cpu counts
detection

Hi,

sorry for the late answer.

Thanks for the answer anyway, better late than never.

quoted

I suppose you mean sysctl command, not systemctl.

That's right. What does lscpu say? Are the NUMA nodes non-contiguous like

this?:

quoted

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):

quoted

On dual CPU systems, it returns 2. On single CPU ones, 1.

I asked the previous question so that we know the actual numa node number

of the second CPU. If it's 8, then sysctl does some renumeration and we can't
use it.

quoted

Bruce, maybe we should just parse lscpu output? That introduces a

dependency, but that may not be such a big deal as lscpu is pretty common.

quoted

Until we are sure that we need it, can we just keep things simple? Perhaps we
can use lscpu if present, and fallback to sysctl output if not.

Piotr says lscpu isn't available on ppc FreeBSD. I think this leaves us with two options:
1. either use sysctl with the risk that it may not return an accurate value
2. not support PPC for numa detection

What do you think?

I think point #2 is more not supporting FreeBSD on PPC for numa detection
rather than not supporting PPC generally, right? Personally, I am just in
favour of #1 for the sake of moving forward and giving us best support with
simplest code. If or when someone does hit this (FreeBSD+PPC) as a problem,
then we can work with them to find best solution for fixing it. Right now
we don't have anyone with the PPC+FreeBSD setup, so I'd rather ignore it
than implement more complicated solutions that we can't test "just in
case".

/Bruce