Re: [PATCH v3 07/16] arch_topology: Use the last level cache information from the cacheinfo

Sudeep Holla
2022-06-06T09:56:05Z

On Thu, Jun 02, 2022 at 04:26:00PM +0200, Dietmar Eggemann wrote:
> On 25/05/2022 10:14, Sudeep Holla wrote:
> > The cacheinfo is now initialised early along with the CPU topology
> > initialisation. Instead of relying on the LLC ID information parsed
> > separately only with ACPI PPTT elsewhere, migrate to use the similar
> > information from the cacheinfo.
> >
> > This is generic for both DT and ACPI systems. The ACPI LLC ID information
> > parsed separately can now be removed from arch specific code.
> >
> > Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
> > ---
> > drivers/base/arch_topology.c | 5 +++--
> > 1 file changed, 3 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/base/arch_topology.c b/drivers/base/arch_topology.c
> > index 765723448b10..4c486e4e6f2f 100644
> > --- a/drivers/base/arch_topology.c
> > +++ b/drivers/base/arch_topology.c
> > @@ -663,7 +663,8 @@ const struct cpumask *cpu_coregroup_mask(int cpu)
> > /* not numa in package, lets use the package siblings */
> > core_mask = &cpu_topology[cpu].core_sibling;
> > }
> > - if (cpu_topology[cpu].llc_id != -1) {
> > +
> > + if (last_level_cache_is_valid(cpu)) {
> > if (cpumask_subset(&cpu_topology[cpu].llc_sibling, core_mask))
> > core_mask = &cpu_topology[cpu].llc_sibling;
> > }
> > @@ -694,7 +695,7 @@ void update_siblings_masks(unsigned int cpuid)
> > for_each_online_cpu(cpu) {
> > cpu_topo = &cpu_topology[cpu];
> >
> > - if (cpu_topo->llc_id != -1 && cpuid_topo->llc_id == cpu_topo->llc_id) {
> > + if (last_level_cache_is_shared(cpu, cpuid)) {
> > cpumask_set_cpu(cpu, &cpuid_topo->llc_sibling);
> > cpumask_set_cpu(cpuid, &cpu_topo->llc_sibling);
> > }
>
> I tested v3 on a Kunpeng920 (w/o CONFIG_NUMA) and it looks
> like that last_level_cache_is_shared() isn't working as
> expected.
>

Thanks a lot for detailed instrumentation, I am unable to identify why it is
not working though. I will take a deeper look later.

--
Regards,
Sudeep