Messages in this thread | | | Date | Thu, 19 Nov 2015 10:16:39 +0530 | From | Viresh Kumar <> | Subject | Re: [PATCH] cpufreq, intel_pstate.c, Fix rounding errors |
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On 18-11-15, 10:55, Prarit Bhargava wrote: > diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c > index 2e31d09..686f024 100644 > --- a/drivers/cpufreq/intel_pstate.c > +++ b/drivers/cpufreq/intel_pstate.c > @@ -1233,6 +1233,8 @@ static int intel_pstate_set_policy(struct cpufreq_policy *policy) > struct cpudata *cpu; > int i; > #endif > + int max_policy_calc; > + > pr_debug("intel_pstate: %s max %u policy->max %u\n", __func__, > policy->cpuinfo.max_freq, policy->max); > if (!policy->cpuinfo.max_freq) > @@ -1249,7 +1251,10 @@ static int intel_pstate_set_policy(struct cpufreq_policy *policy) > limits = &powersave_limits; > limits->min_policy_pct = (policy->min * 100) / policy->cpuinfo.max_freq; > limits->min_policy_pct = clamp_t(int, limits->min_policy_pct, 0 , 100); > - limits->max_policy_pct = (policy->max * 100) / policy->cpuinfo.max_freq; > + > + max_policy_calc = (policy->max * 1000) / policy->cpuinfo.max_freq; > + limits->max_policy_pct = DIV_ROUND_UP(max_policy_calc, 10); > +
Nice catch, but why can't we do this instead:
limits->max_policy_pct = DIV_ROUND_UP(policy->max * 100, policy->cpuinfo.max_freq);
> limits->max_policy_pct = clamp_t(int, limits->max_policy_pct, 0 , 100); > > /* Normalize user input to [min_policy_pct, max_policy_pct] */ > @@ -1269,6 +1274,7 @@ static int intel_pstate_set_policy(struct cpufreq_policy *policy) > int_tofp(100)); > limits->max_perf = div_fp(int_tofp(limits->max_perf_pct), > int_tofp(100)); > + limits->max_perf = round_up(limits->max_perf, 8);
Perhaps you should fix this in a separate patch.
-- viresh
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