2019-11-24 14:10:01

by Vladimir Kondratiev

Subject: [PATCH] mips: cacheinfo: report shared CPU map

Report L1 caches as shared per core; L2 - per cluster.

This fixes "perf" that went crazy if shared_cpu_map attribute not
reported on sysfs, in form of

/sys/devices/system/cpu/cpu*/cache/index*/shared_cpu_list
/sys/devices/system/cpu/cpu*/cache/index*/shared_cpu_map

Signed-off-by: Vladimir Kondratiev <[email protected]>
---
arch/mips/kernel/cacheinfo.c | 27 ++++++++++++++++++++++++++-
1 file changed, 26 insertions(+), 1 deletion(-)

diff --git a/arch/mips/kernel/cacheinfo.c b/arch/mips/kernel/cacheinfo.c
index f777e44653d5..47312c529410 100644
--- a/arch/mips/kernel/cacheinfo.c
+++ b/arch/mips/kernel/cacheinfo.c
@@ -50,6 +50,25 @@ static int __init_cache_level(unsigned int cpu)
return 0;
}

+static void fill_cpumask_siblings(int cpu, cpumask_t *cpu_map)
+{
+ int cpu1;
+
+ for_each_possible_cpu(cpu1)
+ if (cpus_are_siblings(cpu, cpu1))
+ cpumask_set_cpu(cpu1, cpu_map);
+}
+
+static void fill_cpumask_cluster(int cpu, cpumask_t *cpu_map)
+{
+ int cpu1;
+ int cluster = cpu_cluster(&cpu_data[cpu]);
+
+ for_each_possible_cpu(cpu1)
+ if (cpu_cluster(&cpu_data[cpu1]) == cluster)
+ cpumask_set_cpu(cpu1, cpu_map);
+}
+
static int __populate_cache_leaves(unsigned int cpu)
{
struct cpuinfo_mips *c = &current_cpu_data;
@@ -57,14 +76,20 @@ static int __populate_cache_leaves(unsigned int cpu)
struct cacheinfo *this_leaf = this_cpu_ci->info_list;

if (c->icache.waysize) {
+ /* L1 caches are per core */
+ fill_cpumask_siblings(cpu, &this_leaf->shared_cpu_map);
populate_cache(dcache, this_leaf, 1, CACHE_TYPE_DATA);
+ fill_cpumask_siblings(cpu, &this_leaf->shared_cpu_map);
populate_cache(icache, this_leaf, 1, CACHE_TYPE_INST);
} else {
populate_cache(dcache, this_leaf, 1, CACHE_TYPE_UNIFIED);
}

- if (c->scache.waysize)
+ if (c->scache.waysize) {
+ /* L2 cache is per cluster */
+ fill_cpumask_cluster(cpu, &this_leaf->shared_cpu_map);
populate_cache(scache, this_leaf, 2, CACHE_TYPE_UNIFIED);
+ }

if (c->tcache.waysize)
populate_cache(tcache, this_leaf, 3, CACHE_TYPE_UNIFIED);
--
2.20.1

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2019-11-26 19:31:17

by Paul Burton

Subject: Re: [PATCH] mips: cacheinfo: report shared CPU map

Hello,

Vladimir Kondratiev wrote:
> Report L1 caches as shared per core; L2 - per cluster.
>
> This fixes "perf" that went crazy if shared_cpu_map attribute not
> reported on sysfs, in form of
>
> /sys/devices/system/cpu/cpu*/cache/index*/shared_cpu_list
> /sys/devices/system/cpu/cpu*/cache/index*/shared_cpu_map

Applied to mips-fixes.

> commit 3b1313eb32c4
> https://git.kernel.org/mips/c/3b1313eb32c4
>
> Signed-off-by: Vladimir Kondratiev <[email protected]>
> Signed-off-by: Paul Burton <[email protected]>

Thanks,
Paul

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