Date: Thu, 21 May 2015 13:27:04 +0530
From: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
To: Morten Rasmussen <morten.rasmussen@arm.com>
Cc: peterz@infradead.org, mingo@redhat.com, vincent.guittot@linaro.org,
        Dietmar Eggemann <Dietmar.Eggemann@arm.com>, yuyang.du@intel.com,
        preeti@linux.vnet.ibm.com, mturquette@linaro.org, rjw@rjwysocki.net,
        Juri Lelli <Juri.Lelli@arm.com>, sgurrappadi@nvidia.com,
        pang.xunlei@zte.com.cn, linux-kernel@vger.kernel.org,
        linux-pm@vger.kernel.org
Subject: Re: [RFCv4 PATCH 22/34] sched: Calculate energy consumption of
 sched_group
Message-ID: <20150521075702.GA20008@linux.vnet.ibm.com>
Reply-To: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
References: <1431459549-18343-1-git-send-email-morten.rasmussen@arm.com>
 <1431459549-18343-23-git-send-email-morten.rasmussen@arm.com>
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* Morten Rasmussen <morten.rasmussen@arm.com> [2015-05-12 20:38:57]:

[...]
> +/*
> + * cpu_norm_usage() returns the cpu usage relative to a specific capacity,
> + * i.e. it's busy ratio, in the range [0..SCHED_LOAD_SCALE] which is useful for
> + * energy calculations. Using the scale-invariant usage returned by
> + * get_cpu_usage() and approximating scale-invariant usage by:
> + *
> + *   usage ~ (curr_freq/max_freq)*1024 * capacity_orig/1024 * running_time/time
> + *
> + * the normalized usage can be found using the specific capacity.
> + *
> + *   capacity = capacity_orig * curr_freq/max_freq
> + *
> + *   norm_usage = running_time/time ~ usage/capacity
> + */
> +static unsigned long cpu_norm_usage(int cpu, unsigned long capacity)
> +{
> +	int usage = __get_cpu_usage(cpu);

__get_cpu_usage is introduced in next patch "sched: Extend sched_group_energy
to test load-balancing decisions", applying the series with this patch as top
most patch breaks the build.

kernel/sched/fair.c: In function ‘cpu_norm_usage’:
kernel/sched/fair.c:4830:2: error: implicit declaration of function ‘__get_cpu_usage’ [-Werror=implicit-function-declaration]
  int usage = __get_cpu_usage(cpu);
  ^

Given that __get_cpu_usage(), take additional parameter - delta. get_cpu_usage()
should have been used here.

Thanks,
Kamalesh

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