Messages in this thread | | | Date | Thu, 2 Jun 2022 16:26:00 +0200 | Subject | Re: [PATCH v3 07/16] arch_topology: Use the last level cache information from the cacheinfo | From | Dietmar Eggemann <> |
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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.
I instrumented cpu_coregroup_mask() like:
const struct cpumask *cpu_coregroup_mask(int cpu) { const cpumask_t *core_mask = cpumask_of_node(cpu_to_node(cpu));
if (cpumask_subset(&cpu_topology[cpu].core_sibling, core_mask)) { core_mask = &cpu_topology[cpu].core_sibling; (1) }
(2)
if (last_level_cache_is_valid(cpu)) { if (cpumask_subset(&cpu_topology[cpu].llc_sibling, core_mask)) core_mask = &cpu_topology[cpu].llc_sibling; (3) }
if (IS_ENABLED(CONFIG_SCHED_CLUSTER) && cpumask_subset(core_mask, &cpu_topology[cpu].cluster_sibling)) core_mask = &cpu_topology[cpu].cluster_sibling; (4)
(5) return core_mask; }
and got:
(A) v3 patch-set:
[ 11.561133] (1) cpu_coregroup_mask[0]=0-47 [ 11.565670] (2) last_level_cache_is_valid(0)=1 [ 11.570587] (3) cpu_coregroup_mask[0]=0 <-- llc_sibling=0 (should be 0-23) [ 11.574833] (4) cpu_coregroup_mask[0]=0-3 <-- Altra hack kicks in! [ 11.579275] (5) cpu_coregroup_mask[0]=0-3
# cat /sys/kernel/debug/sched/domains/cpu0/domain*/name CLS DIE
# cat /proc/schedstat | awk '{print $1 " " $2 }' | grep ^[cd] | head -3 cpu0 0 domain0 00000000,00000000,0000000f domain1 ffffffff,ffffffff,ffffffff
So the MC domain is missing.
(B) mainline as reference (cpu_coregroup_mask() slightly different):
[ 11.585008] (1) cpu_coregroup_mask[0]=0-47 [ 11.589544] (3) cpu_coregroup_mask[0]=0-23 <-- !!! [ 11.594079] (5) cpu_coregroup_mask[0]=0-23
# cat /sys/kernel/debug/sched/domains/cpu0/domain*/name CLS MC <-- !!! DIE
# cat /proc/schedstat | awk '{print $1 " " $2 }' | grep ^[cd] | head -4 cpu0 0 domain0 00000000,00000000,0000000f domain1 00000000,00000000,00ffffff <-- !!! domain2 ffffffff,ffffffff,ffffffff
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