[Powerpc-utils-devel] [PATCH] Fix ppc64_cpu --threads-per-core when --smt value set

[Mamatha I. <mam...@li...>]

Problem: ppc64_cpu --threads-per-core gives wrong data when --smt value set

This patch will resolve the above issue and display the correct values of threads-per-core
for the ppc64_cpu command when --smt value is set.

I have used the following equation to calculate threads_per_core as per lscpu command.

	threads_per_core = nthreads / ncores

***********************************************
Test results:

CASE 1:

./src/ppc64_cpu --smt=on
[root@llmjuno03b powerpc-utils]# ./src/ppc64_cpu --threads-per-core
Threads per core: 4

lscpu output:
Thread(s) per core:    4
------------------------------------------
CASE 2:

./src/ppc64_cpu --smt=2
[root@llmjuno03b powerpc-utils]# ./src/ppc64_cpu --threads-per-core
Threads per core: 2

lscpu output:
Thread(s) per core:    2
--------------------------------------------------
CASE 3:

./src/ppc64_cpu --smt=1
[root@llmjuno03b powerpc-utils]# ./src/ppc64_cpu --threads-per-core
Threads per core: 1

lscpu output:
Thread(s) per core:    1
-------------------------------------------------

Signed-off-by: Mamatha Inamdar <mam...@li...>
---
 src/ppc64_cpu.c |   15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/src/ppc64_cpu.c b/src/ppc64_cpu.c
index 4df4cdc..a3cfed0 100644
--- a/src/ppc64_cpu.c
+++ b/src/ppc64_cpu.c
@@ -56,6 +56,7 @@ static int counters[MAX_NR_CPUS];
 static int threads_per_cpu = 0;
 static int cpus_in_system = 0;
 static int threads_in_system = 0;
+static int threads_per_core = 0;
 
 static int do_info(void);
 
@@ -529,9 +530,21 @@ static int do_smt(char *state)
 	return rc;
 }
 
+/* Threads per core */
 static inline void do_threads_per_core()
 {
-	printf("Threads per core: %d\n", threads_per_cpu);
+	int i, j;
+	int nthreads;    /* number of threads online */
+
+	/* Calculate number of threads present on the system */
+	for (j = 0; j < threads_in_system; j += threads_per_cpu) {
+		for (i = 0; i < threads_per_cpu; i++)
+			nthreads += cpu_online(j + i);
+	}
+
+	/* Calculate threads per core = nthreads / ncores */
+	threads_per_core = nthreads / cpus_in_system;
+	printf("Threads per core: %d\n", threads_per_core);
 }
 
 static int do_subcores_per_core(char *state)