Messages in this thread | | | Date | Mon, 5 Feb 2024 18:46:33 -0800 | From | Ricardo Neri <> | Subject | Re: [PATCH v3 1/4] sched/fair: add SD_CLUSTER in comments |
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On Fri, Feb 02, 2024 at 03:27:32PM +0100, Valentin Schneider wrote: > > Subject nit: the prefix should be sched/topology > > On 01/02/24 19:54, alexs@kernel.org wrote: > > From: Alex Shi <alexs@kernel.org> > > > > The description of SD_CLUSTER is missing. Add it. > > > > Signed-off-by: Alex Shi <alexs@kernel.org> > > To: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> > > To: Valentin Schneider <vschneid@redhat.com> > > To: Vincent Guittot <vincent.guittot@linaro.org> > > To: Juri Lelli <juri.lelli@redhat.com> > > To: Peter Zijlstra <peterz@infradead.org> > > To: Ingo Molnar <mingo@redhat.com> > > --- > > kernel/sched/topology.c | 1 + > > 1 file changed, 1 insertion(+) > > > > diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c > > index 10d1391e7416..8b45f16a1890 100644 > > --- a/kernel/sched/topology.c > > +++ b/kernel/sched/topology.c > > @@ -1554,6 +1554,7 @@ static struct cpumask ***sched_domains_numa_masks; > > * function: > > * > > * SD_SHARE_CPUCAPACITY - describes SMT topologies > > + * SD_CLUSTER - describes CPU Cluster topologies > > So I know this is the naming we've gone for the "Cluster" naming, but this > comment isn't really explaining anything. > > include/linux/sched/sd_flags.h has a bit more info already: > * Domain members share CPU cluster (LLC tags or L2 cache)
I also thought of this, but I didn't want to suggest to repeat in topolog.c what is described in sd_flags.h.
Maybe it is better to remove the descriptions of all flags here and instead direct the reader to sd_flags.h?
> > I had to go through a bit of git history to remember what the CLUSTER thing > was about, how about this: > > * SD_CLUSTER - describes shared shared caches, cache tags or busses
AFAIK, this describes a subset of CPUs in the package that share a resource, likely L2 cache.
> * SD_SHARE_PKG_RESOURCES - describes shared LLC cache > > And looking at this it would make sense to: > rename SD_CLUSTER into SD_SHARE_PKG_RESOURCES
but not all CPUs in the package share the resource
> rename SD_SHARE_PKG_RESOURCES into SD_SHARE_LLC > but that's another topic... >
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