Hi,


On 09/17/2017 08:50 PM, Xiongfeng Wang wrote:

Hi Jeremy,

On 2017/9/15 2:49, Jeremy Linton wrote:

quoted

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 <redacted>
---
  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

quoted

  
  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).

quoted

  			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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