Messages in this thread | | | Date | Thu, 21 Feb 2013 21:03:44 +0530 | Subject | Re: [PATCH v2 linux-next] cpufreq: ondemand: Calculate gradient of CPU load to early increase frequency | From | Viresh Kumar <> |
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Hi Again,
On Thu, Feb 21, 2013 at 5:01 PM, Stratos Karafotis <stratosk@semaphore.gr> wrote:
> diff --git a/drivers/cpufreq/cpufreq_ondemand.c b/drivers/cpufreq/cpufreq_ondemand.c > @@ -168,16 +174,29 @@ static void od_check_cpu(int cpu, unsigned int load_freq) > struct cpufreq_policy *policy = dbs_info->cdbs.cur_policy; > struct dbs_data *dbs_data = policy->governor_data; > struct od_dbs_tuners *od_tuners = dbs_data->tuners; > + unsigned int prev_load_freq; > > dbs_info->freq_lo = 0; > > + /* > + * Calculate the gradient of load_freq. If it is too steep we assume > + * that the load will go over up_threshold in next iteration(s) and > + * we increase the frequency immediately > + */ > + if (od_tuners->early_demand) { > + prev_load_freq = dbs_info->prev_load_freq; > + dbs_info->prev_load_freq = load_freq; > + > + if (load_freq > prev_load_freq && (load_freq - prev_load_freq > > + od_tuners->grad_up_threshold * policy->cur)) { > + dbs_freq_increase(dbs_info, policy, policy->max); > + return; > + } > + } > + > /* Check for frequency increase */ > if (load_freq > od_tuners->up_threshold * policy->cur) { > - /* 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); > + dbs_freq_increase(dbs_info, policy, policy->max); > return; > }
Not really against your implementation, but this is what i thought of how it should look like (initially when i reviewed your V1)
int boost_freq = 0;
if (od_tuners->early_demand) { if (load_freq > dbs_info->prev_load_freq && (load_freq - dbs_info->prev_load_freq > od_tuners->grad_up_threshold * policy->cur)) { boost_freq = 1; }
dbs_info->prev_load_freq = load_freq; }
/* Check for frequency increase */ if (boost_freq || (load_freq > od_tuners->up_threshold * policy->cur)) { increase-freq;
This would get rid of duplicate calls to increase_freq() and also avoid changing its prototype.
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