path: root/arch/s390/include/asm/topology.h
diff options
authorMartin Schwidefsky <>2015-01-14 17:52:10 +0100
committerMartin Schwidefsky <>2015-01-22 12:16:01 +0100
commit10ad34bc76dfbc49bda327a13012f6754c0c72e0 (patch)
tree4d76fb6882da2eb3e77b53c4fe64f6367ffbd79d /arch/s390/include/asm/topology.h
parent1f6b83e5e4d3aed46eac1d219322fba9c7341cd8 (diff)
s390: add SMT support
The multi-threading facility is introduced with the z13 processor family. This patch adds code to detect the multi-threading facility. With the facility enabled each core will surface multiple hardware threads to the system. Each hardware threads looks like a normal CPU to the operating system with all its registers and properties. The SCLP interface reports the SMT topology indirectly via the maximum thread id. Each reported CPU in the result of a read-scp-information is a core representing a number of hardware threads. To reflect the reduced CPU capacity if two hardware threads run on a single core the MT utilization counter set is used to normalize the raw cputime obtained by the CPU timer deltas. This scaled cputime is reported via the taskstats interface. The normal /proc/stat numbers are based on the raw cputime and are not affected by the normalization. Signed-off-by: Martin Schwidefsky <>
Diffstat (limited to 'arch/s390/include/asm/topology.h')
1 files changed, 4 insertions, 0 deletions
diff --git a/arch/s390/include/asm/topology.h b/arch/s390/include/asm/topology.h
index 56af53093d24..c4fbb9527c5c 100644
--- a/arch/s390/include/asm/topology.h
+++ b/arch/s390/include/asm/topology.h
@@ -9,9 +9,11 @@ struct cpu;
struct cpu_topology_s390 {
+ unsigned short thread_id;
unsigned short core_id;
unsigned short socket_id;
unsigned short book_id;
+ cpumask_t thread_mask;
cpumask_t core_mask;
cpumask_t book_mask;
@@ -19,6 +21,8 @@ struct cpu_topology_s390 {
extern struct cpu_topology_s390 cpu_topology[NR_CPUS];
#define topology_physical_package_id(cpu) (cpu_topology[cpu].socket_id)
+#define topology_thread_id(cpu) (cpu_topology[cpu].thread_id)
+#define topology_thread_cpumask(cpu) (&cpu_topology[cpu].thread_mask)
#define topology_core_id(cpu) (cpu_topology[cpu].core_id)
#define topology_core_cpumask(cpu) (&cpu_topology[cpu].core_mask)
#define topology_book_id(cpu) (cpu_topology[cpu].book_id)