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

[Bruce Richardson <bruce.richardson@intel.com>]

On Tue, Aug 31, 2021 at 07:54:16AM +0000, Juraj Linkeš wrote:
> 
> 
> > -----Original Message-----
> > From: Piotr Kubaj <pkubaj@anongoth.pl>
> > Sent: Tuesday, August 31, 2021 2:55 AM
> > To: Juraj Linkeš <juraj.linkes@pantheon.tech>
> > Cc: David Christensen <drc@linux.vnet.ibm.com>; 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.
> 
> > 
> > I suppose you mean sysctl command, not systemctl.
> > 
> 
> That's right. What does lscpu say? Are the NUMA nodes non-contiguous like this?:
> 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):
> 
> > 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.
> 
> 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.
> 
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.