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

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

[Abhishek Goel]

cpuidle_monitor used to assume that cpu0 is always online. Now the
cpuidle_monitor function searches for the first online cpu and use
it, instead of always using cpu0 which may not be online.

Signed-off-by: Abhishek Goel <huntbag@linux.vnet.ibm.com>
---
 tools/power/cpupower/utils/idle_monitor/cpuidle_sysfs.c | 14 +++++++++++---
 1 file changed, 11 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..adacf99 100644
--- a/tools/power/cpupower/utils/idle_monitor/cpuidle_sysfs.c
+++ b/tools/power/cpupower/utils/idle_monitor/cpuidle_sysfs.c
@@ -130,15 +130,23 @@ static struct cpuidle_monitor *cpuidle_register(void)
 {
 	int num;
 	char *tmp;
+	int first_online_cpu;
+
+	for (num = 0; num < cpu_count; num++) {
+		if (cpupower_is_cpu_online(num))
+			break;
+	};
+	first_online_cpu = num;
 
 	/* 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(first_online_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(first_online_cpu, num);
 		if (tmp == NULL)
 			continue;
 
@@ -146,7 +154,7 @@ 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(first_online_cpu, num);
 		if (tmp == NULL)
 			continue;
 		strncpy(cpuidle_cstates[num].desc, tmp,	CSTATE_DESC_LEN - 1);
-- 
2.9.3

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

[Gautham R Shenoy]

On Fri, Sep 22, 2017 at 04:32:18PM +0530, Abhishek Goel wrote:
> cpuidle_monitor used to assume that cpu0 is always online.

On what platform is this assumption not valid and what is the problem
caused due to this.

> Now the
> cpuidle_monitor function searches for the first online cpu and use
> it, instead of always using cpu0 which may not be online.

Mention that this is the fix performed by this patch.

> 
> Signed-off-by: Abhishek Goel <huntbag@linux.vnet.ibm.com>
> ---
>  tools/power/cpupower/utils/idle_monitor/cpuidle_sysfs.c | 14 +++++++++++---
>  1 file changed, 11 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..adacf99 100644
> --- a/tools/power/cpupower/utils/idle_monitor/cpuidle_sysfs.c
> +++ b/tools/power/cpupower/utils/idle_monitor/cpuidle_sysfs.c
> @@ -130,15 +130,23 @@ static struct cpuidle_monitor *cpuidle_register(void)
>  {
>  	int num;
>  	char *tmp;
> +	int first_online_cpu;
> +
> +	for (num = 0; num < cpu_count; num++) {
> +		if (cpupower_is_cpu_online(num))
> +			break;
> +	};

Don't we have an API that gives the list by parsing
"/sys/devices/system/cpu/online" ?


> +	first_online_cpu = num;
>
>  	/* 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(first_online_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(first_online_cpu, num);
>  		if (tmp == NULL)
>  			continue;
> 
> @@ -146,7 +154,7 @@ 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(first_online_cpu, num);
>  		if (tmp == NULL)
>  			continue;
>  		strncpy(cpuidle_cstates[num].desc, tmp,
>CSTATE_DESC_LEN - 1);


Looks ok to me otherwise.

> -- 
> 2.9.3
> 

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

[Abhishek Goel]

cpuidle_monitor used to assume that cpu0 is always online. Now the
cpuidle_monitor function searches for the first online cpu and use
it, instead of always using cpu0 which maynot be online.

Signed-off-by: Abhishek Goel <huntbag@linux.vnet.ibm.com>
---
 tools/power/cpupower/utils/idle_monitor/cpuidle_sysfs.c | 6 +++---
 1 file changed, 3 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 055a4fa..1cfba02 100644
--- a/tools/power/cpupower/utils/idle_monitor/cpuidle_sysfs.c
+++ b/tools/power/cpupower/utils/idle_monitor/cpuidle_sysfs.c
@@ -132,13 +132,13 @@ static struct cpuidle_monitor *cpuidle_register(void)
 	char *tmp;
 	int first_online_cpu;
 
-	for (num = 0; num < cpu_count; num++){
+	for (num = 0; num < cpu_count; num++) {
 		if (cpupower_is_cpu_online(num))
 			break;
 	};
 	first_online_cpu = num;
-	
-	/* Assume idle state count is the same for all CPUs */ 
+
+	/* Assume idle state count is the same for all CPUs */
 	cpuidle_sysfs_monitor.hw_states_num = cpuidle_state_count(first_online_cpu);
 
 	if (cpuidle_sysfs_monitor.hw_states_num <= 0)
-- 
2.9.3