Re: [PATCH v2] eal: fix undetected NUMA nodes

[David Marchand <david.marchand@redhat.com>]

On Tue, Mar 18, 2025 at 6:42 PM Bruce Richardson
<bruce.richardson@intel.com> wrote:
>
> On Wed, Mar 05, 2025 at 04:24:58PM +0000, Bruce Richardson wrote:
> > In cases where the number of cores on a given socket is greater than
> > RTE_MAX_LCORES, then EAL will be unaware of all the sockets/numa nodes
> > on a system. Fix this limitation by having the EAL probe the NUMA node
> > for cores it isn't going to use, and recording that for completeness.
> >
> > This is necessary as memory is tracked per node, and with the --lcores
> > parameters our app lcores may be on different sockets than the lcore ids
> > may imply. For example, lcore 0 is on socket zero, but if app is run
> > with --lcores=0@64, then DPDK lcore 0 may be on socket one, so DPDK
> > needs to be aware of that socket.
> >
> > Fixes: 952b20777255 ("eal: provide API for querying valid socket ids")
> > Cc: stable@dpdk.org
> >
> > Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
> >
> > ---
> > v2: handle case where RTE_MAX_LCORE > CPU_SETSIZE (i.e. >1024)
> > ---
> >  lib/eal/common/eal_common_lcore.c | 17 ++++++++++++-----
> >  1 file changed, 12 insertions(+), 5 deletions(-)
> >
> Ping for review.
>
> For anyone wanting to test:
>          To reproduce the issue, do a build of DPDK with max_lcores option
> set to less than the number of physical cores you have on a socket.

You also need to have those cores contiguous for a numa node which is
quite frequent on the systems in my lab.
But anyway, the bug is not hard to understand, I'll reply on the patch itself.


-- 
David Marchand