Hi,
On 09/17/2017 08:50 PM, Xiongfeng Wang wrote:
Hi Jeremy,
On 2017/9/15 2:49, Jeremy Linton wrote:
Many modern machines have cluster on die (COD) non-uniformity
as well as the traditional multi-socket architectures. Reusing
the multi-socket or NUMA on die concepts for these (as arm64 does)
breaks down when presented with actual multi-socket/COD machines.
Similar, problems are also visible on some x86 machines so it
seems appropriate to start abstracting and making these topologies
visible.
To start, a topology_cod_id() macro is added which defaults to returning
the same information as topology_physical_package_id(). Moving forward
we can start to spit out the differences.
For arm64, an additional package_id is added to the cpu_topology array.
Initially this will be equal to the cluster_id as well.
Signed-off-by: Jeremy Linton <jeremy.linton@xxxxxxx>
---
arch/arm64/include/asm/topology.h | 4 +++-
arch/arm64/kernel/topology.c | 8 ++++++--
include/linux/topology.h | 3 +++
3 files changed, 12 insertions(+), 3 deletions(-)
diff --git a/arch/arm64/include/asm/topology.h b/arch/arm64/include/asm/topology.h
index 8b57339823e9..bd7517960d39 100644
--- a/arch/arm64/include/asm/topology.h
+++ b/arch/arm64/include/asm/topology.h
@@ -7,13 +7,15 @@ struct cpu_topology {
int thread_id;
int core_id;
int cluster_id;
+ int package_id;
cpumask_t thread_sibling;
cpumask_t core_sibling;
};
'core_sibling' will be updated by 'update_siblings_masks()' to represent cores in a cluster;
Can we add a cpumask_t field to represent cores in a package? So that 'lstopo' can use this
cpumask_t to display the right information.
So, the change below modifies update_siblings_mask() to utilize the
package_id. Per the ABI the ..cpuX/topology/physical_package_id is
shared between the core_siblings/core_siblings_list. What
physical_package_id means can vary per architecture, but the siblings
list needs to be the cores with the same phyiscal_package (AFAIK, feel
free to correct my understanding). That rule should be enforced by this
patch set.
I suspect if your running these patches, and the lstopo output looks
strange its because your on a machine where the thread_id has been
assigned the cluster_id in the later patch set.
Thanks,
Xiongfeng Wang
extern struct cpu_topology cpu_topology[NR_CPUS];
-#define topology_physical_package_id(cpu) (cpu_topology[cpu].cluster_id)
+#define topology_physical_package_id(cpu) (cpu_topology[cpu].package_id)
+#define topology_cod_id(cpu) (cpu_topology[cpu].cluster_id)
#define topology_core_id(cpu) (cpu_topology[cpu].core_id)
#define topology_core_cpumask(cpu) (&cpu_topology[cpu].core_sibling)
#define topology_sibling_cpumask(cpu) (&cpu_topology[cpu].thread_sibling)
diff --git a/arch/arm64/kernel/topology.c b/arch/arm64/kernel/topology.c
index 8d48b233e6ce..9147e5b6326d 100644
--- a/arch/arm64/kernel/topology.c
+++ b/arch/arm64/kernel/topology.c
@@ -67,6 +67,8 @@ static int __init parse_core(struct device_node *core, int cluster_id,
leaf = false;
cpu = get_cpu_for_node(t);
if (cpu >= 0) {
+ /* maintain DT cluster == package behavior */
+ cpu_topology[cpu].package_id = cluster_id;
cpu_topology[cpu].cluster_id = cluster_id;
cpu_topology[cpu].core_id = core_id;
cpu_topology[cpu].thread_id = i;
@@ -88,7 +90,7 @@ static int __init parse_core(struct device_node *core, int cluster_id,
core);
return -EINVAL;
}
-
+ cpu_topology[cpu].package_id = cluster_id;
cpu_topology[cpu].cluster_id = cluster_id;
cpu_topology[cpu].core_id = core_id;
} else if (leaf) {
@@ -228,7 +230,7 @@ static void update_siblings_masks(unsigned int cpuid)
for_each_possible_cpu(cpu) {
cpu_topo = &cpu_topology[cpu];
- if (cpuid_topo->cluster_id != cpu_topo->cluster_id)
+ if (cpuid_topo->package_id != cpu_topo->package_id)
(note here that core_siblings now reflect the package_id rather than the
cluster_id. This only matters if cluster_id!=package_id).
continue;
cpumask_set_cpu(cpuid, &cpu_topo->core_sibling);
@@ -273,6 +275,7 @@ void store_cpu_topology(unsigned int cpuid)
MPIDR_AFFINITY_LEVEL(mpidr, 2) << 8 |
MPIDR_AFFINITY_LEVEL(mpidr, 3) << 16;
}
+ cpuid_topo->package_id = cpuid_topo->cluster_id;
pr_debug("CPU%u: cluster %d core %d thread %d mpidr %#016llx\n",
cpuid, cpuid_topo->cluster_id, cpuid_topo->core_id,
@@ -292,6 +295,7 @@ static void __init reset_cpu_topology(void)
cpu_topo->thread_id = -1;
cpu_topo->core_id = 0;
cpu_topo->cluster_id = -1;
+ cpu_topo->package_id = -1;
cpumask_clear(&cpu_topo->core_sibling);
cpumask_set_cpu(cpu, &cpu_topo->core_sibling);
diff --git a/include/linux/topology.h b/include/linux/topology.h
index cb0775e1ee4b..4660749a7303 100644
--- a/include/linux/topology.h
+++ b/include/linux/topology.h
@@ -184,6 +184,9 @@ static inline int cpu_to_mem(int cpu)
#ifndef topology_physical_package_id
#define topology_physical_package_id(cpu) ((void)(cpu), -1)
#endif
+#ifndef topology_cod_id /* cluster on die */
+#define topology_cod_id(cpu) topology_physical_package_id(cpu)
+#endif
#ifndef topology_core_id
#define topology_core_id(cpu) ((void)(cpu), 0)
#endif
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