[PATCH v3] cpupower : Fix cpupower working when cpu0 is offline

[PATCH v3] cpupower : Fix cpupower working when cpu0 is offline

[Abhishek Goel]

cpuidle_monitor used to assume that cpu0 is always online which is not
a valid assumption on POWER machines. This patch fixes this by getting
the cpu on which the current thread is running, instead of always using
cpu0 for monitoring which may not be online.

Signed-off-by: Abhishek Goel <huntbag@linux.vnet.ibm.com>
---
 tools/power/cpupower/utils/idle_monitor/cpuidle_sysfs.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/tools/power/cpupower/utils/idle_monitor/cpuidle_sysfs.c b/tools/power/cpupower/utils/idle_monitor/cpuidle_sysfs.c
index 1b5da00..5b3205f 100644
--- a/tools/power/cpupower/utils/idle_monitor/cpuidle_sysfs.c
+++ b/tools/power/cpupower/utils/idle_monitor/cpuidle_sysfs.c
@@ -130,15 +130,18 @@ static struct cpuidle_monitor *cpuidle_register(void)
 {
 	int num;
 	char *tmp;
+	int this_cpu;
+
+	this_cpu = sched_getcpu();
 
 	/* Assume idle state count is the same for all CPUs */
-	cpuidle_sysfs_monitor.hw_states_num = cpuidle_state_count(0);
+	cpuidle_sysfs_monitor.hw_states_num = cpuidle_state_count(this_cpu);
 
 	if (cpuidle_sysfs_monitor.hw_states_num <= 0)
 		return NULL;
 
 	for (num = 0; num < cpuidle_sysfs_monitor.hw_states_num; num++) {
-		tmp = cpuidle_state_name(0, num);
+		tmp = cpuidle_state_name(this_cpu, num);
 		if (tmp == NULL)
 			continue;
 
@@ -146,7 +149,7 @@ static struct cpuidle_monitor *cpuidle_register(void)
 		strncpy(cpuidle_cstates[num].name, tmp, CSTATE_NAME_LEN - 1);
 		free(tmp);
 
-		tmp = cpuidle_state_desc(0, num);
+		tmp = cpuidle_state_desc(this_cpu, num);
 		if (tmp == NULL)
 			continue;
 		strncpy(cpuidle_cstates[num].desc, tmp,	CSTATE_DESC_LEN - 1);
-- 
2.9.3

Re: [PATCH v3] cpupower : Fix cpupower working when cpu0 is offline

[Shuah Khan]

On 11/15/2017 01:40 AM, Abhishek Goel wrote:
> cpuidle_monitor used to assume that cpu0 is always online which is not
> a valid assumption on POWER machines. This patch fixes this by getting
> the cpu on which the current thread is running, instead of always using
> cpu0 for monitoring which may not be online.
> 
> Signed-off-by: Abhishek Goel <huntbag@linux.vnet.ibm.com>
> ---
>  tools/power/cpupower/utils/idle_monitor/cpuidle_sysfs.c | 9 ++++++---
>  1 file changed, 6 insertions(+), 3 deletions(-)
> 

Thanks. I will queue this for 4.15-rc2

-- SHuah