Re: [PATCH] rt-numa: Use a reasonable default max CPU value.

["Ahmed S. Darwish" <darwi@linutronix.de>]

On Mon, 16 Jan 2023, John Kacur wrote:
>
> On Thu, 12 Jan 2023, Sebastian Andrzej Siewior wrote:
>
> > numa_num_task_cpus() returns here > 100 CPUs while the system has only
> > 32 populated. The BIOS assumes that I can probably use larger CPUs (with
> > more cores) on the socket so the number of "configured CPUs" is rather
> > high.
> > For default configuration, only with the -S option, it makes sense to
> > use the current affinity instead looking at the number of possible CPUs
> > which could be brought online. It still depends on the affinity of the
> > created threads if the additional CPUs can be used. In a container setup
> > this may not be the case.
> >
> > Use sched_getaffinity() to figure out the number of possible CPUs.
...
>
> In cyclictest we have
>
> 	if (num_threads == -1)
> 		num_threads = get_available_cpus(affinity_mask);
>
>
> But the num_threads can be set to -1 in OPT_THREADS too,
> not just for OPT_SMP

A sane default for --smp, which is almost-always used in sane cyclictest
invocations, is still valuable IMHO.

Thanks,

--
Ahmed S. Darwish
Linutronix GmbH