2017-09-22 11:03:47

by Abhishek Goel

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

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 <[email protected]>
---
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

2017-09-26 10:12:47

by Gautham R Shenoy

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

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 <[email protected]>
> ---
> 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
>