linux-kernel - Re: [PATCH v2] cpupower : Fix cpupower working when cpu0 is offline

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Message-Id: <b1ae1a14-b354-6bc5-6118-87c7b65ce8a1@linux.vnet.ibm.com>
Date:   Tue, 7 Nov 2017 14:28:22 +0530
From:   Abhishek <huntbag@...ux.vnet.ibm.com>
To:     linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org
Cc:     Shuah Khan <shuahkh@....samsung.com>,
        Shuah Khan <shuah@...nel.org>,
        Thomas Renninger <trenn@...e.com>
Subject: Re: [PATCH v2] cpupower : Fix cpupower working when cpu0 is offline

Hi,

Can you have a look at it?

Thanks and Regards,

Abhishek Goel

System Engineer

IBM India Pvt. Ltd.


On 11/07/2017 12:50 PM, 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 searching
> for the first online cpu and uses it, instead of always using cpu0 for
> monitoring which may not be online.
>
> Signed-off-by: Abhishek Goel <huntbag@...ux.vnet.ibm.com>
> ---
> v2: Commit message updated.
> ---
>   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);