Re: [PATCH v3 0/3] sched/topology: optimize topology_span_sane()

[Christophe JAILLET]

Le 06/11/2024 à 17:28, Yury Norov a écrit :
> Last reminder. If you guys don't care, I don't care either.

Hi Yury,

I'm the only one in the To: field, but I'm not a maintainer.

Maybe, try to move people in the Cc: field into the To: field, to 
increase visibility?

CJ

> On Mon, Sep 30, 2024 at 12:15:02PM -0700, Yury Norov wrote:
> > Ping again?
> >
> > On Sat, Sep 14, 2024 at 09:54:43AM -0700, Yury Norov wrote:
> > > Ping?
> > >
> > > On Mon, Sep 02, 2024 at 11:36:04AM -0700, Yury Norov wrote:
> > > > The function may call cpumask_equal with tl->mask(cpu) == tl->mask(i),
> > > > even when cpu != i. In such case, cpumask_equal() would always return
> > > > true, and we can proceed to the next iteration immediately.
> > > >
> > > > Valentin Schneider shares on it:
> > > >
> > > >    PKG can potentially hit that condition, and so can any
> > > >    sched_domain_mask_f that relies on the node masks...
> > > >
> > > >    I'm thinking ideally we should have checks in place to
> > > >    ensure all node_to_cpumask_map[] masks are disjoint,
> > > >    then we could entirely skip the levels that use these
> > > >    masks in topology_span_sane(), but there's unfortunately
> > > >    no nice way to flag them... Also there would be cases
> > > >    where there's no real difference between PKG and NODE
> > > >    other than NODE is still based on a per-cpu cpumask and
> > > >    PKG isn't, so I don't see a nicer way to go about this.
> > > >
> > > > v1: https://lore.kernel.org/lkml/ZrJk00cmVaUIAr4G@yury-ThinkPad/T/
> > > > v2: https://lkml.org/lkml/2024/8/7/1299
> > > > v3:
> > > >   - add topology_cpumask_equal() helper in #3;
> > > >   - re-use 'cpu' as an iterator int the for_each_cpu() loop;
> > > >   - add proper versioning for all patches.
> > > >
> > > > Yury Norov (3):
> > > >    sched/topology: pre-compute topology_span_sane() loop params
> > > >    sched/topology: optimize topology_span_sane()
> > > >    sched/topology: reorganize topology_span_sane() checking order
> > > >
> > > >   kernel/sched/topology.c | 29 +++++++++++++++++++++++++----
> > > >   1 file changed, 25 insertions(+), 4 deletions(-)
> > > >
> > > > --
> > > > 2.43.0