On Friday, May 31, 2013 02:24:59 PM Viresh Kumar wrote:
> On 31 May 2013 02:37, Stratos Karafotis <stratosk@xxxxxxxxxxxx> wrote:
>
> Ahh.. earlier mail got sent without me doing complete review :(
>
> > diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
> > +static void od_check_cpu(int cpu, unsigned int load)
> > {
> > struct od_cpu_dbs_info_s *dbs_info = &per_cpu(od_cpu_dbs_info, cpu);
> > struct cpufreq_policy *policy = dbs_info->cdbs.cur_policy;
> > @@ -176,29 +170,17 @@ static void od_check_cpu(int cpu, unsigned int load_freq)
> > dbs_info->freq_lo = 0;
> >
> > /* Check for frequency increase */
> > - if (load_freq > od_tuners->up_threshold * policy->cur) {
> > + if (load > od_tuners->up_threshold) {
>
> Chances of this getting hit are minimal now.. I don't know if keeping
> this will change anything now :)
>
> > /* If switching to max speed, apply sampling_down_factor */
> > if (policy->cur < policy->max)
> > dbs_info->rate_mult =
> > od_tuners->sampling_down_factor;
> > dbs_freq_increase(policy, policy->max);
> > return;
> > - }
> > -
> > - /* Check for frequency decrease */
> > - /* if we cannot reduce the frequency anymore, break out early */
> > - if (policy->cur == policy->min)
> > - return;
> > -
> > - /*
> > - * The optimal frequency is the frequency that is the lowest that can
> > - * support the current CPU usage without triggering the up policy. To be
> > - * safe, we focus 10 points under the threshold.
> > - */
> > - if (load_freq < od_tuners->adj_up_threshold
> > - * policy->cur) {
> > + } else {
> > + /* Calculate the next frequency proportional to load */
> > unsigned int freq_next;
> > - freq_next = load_freq / od_tuners->adj_up_threshold;
> > + freq_next = load * policy->max / 100;
>
> Rafael asked why you believe this is the right formula and I really couldn't
> find an appropriate answer to that, sorry :(
Right, it would be good to explain that.
"Proportional to load" means C * load, so why is "policy->max / 100" *the* right C?
Rafael
--
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
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