Messages in this thread | | | Date | Thu, 25 Feb 2016 10:08:40 +0100 | From | Peter Zijlstra <> | Subject | Re: [RFC/RFT][PATCH v3 2/2] cpufreq: schedutil: Switching frequencies from interrupt context |
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On Thu, Feb 25, 2016 at 12:30:43AM +0100, Rafael J. Wysocki wrote: > +unsigned int acpi_cpufreq_fast_switch(struct cpufreq_policy *policy, > + unsigned int target_freq) > +{ > + struct acpi_cpufreq_data *data = policy->driver_data; > + struct cpufreq_frequency_table *entry; > + struct acpi_processor_performance *perf; > + unsigned int uninitialized_var(next_perf_state); > + unsigned int uninitialized_var(next_freq); > + unsigned int best_diff; > + > + for (entry = data->freq_table, best_diff = UINT_MAX; > + entry->frequency != CPUFREQ_TABLE_END; entry++) { > + unsigned int diff, freq = entry->frequency; > + > + if (freq == CPUFREQ_ENTRY_INVALID) > + continue; > + > + diff = abs(freq - target_freq);
Why would you consider frequencies that are below where you want to be?
> + if (diff >= best_diff) > + continue; > + > + best_diff = diff; > + next_perf_state = entry->driver_data; > + next_freq = freq; > + if (best_diff == 0) > + goto found; > + } > + if (best_diff == UINT_MAX) > + return CPUFREQ_ENTRY_INVALID; > + > + found: > + perf = to_perf_data(data); > + if (perf->state == next_perf_state) { > + if (unlikely(data->resume)) > + data->resume = 0; > + else > + return next_freq; > + } > + > + data->cpu_freq_fast_write(perf->states[next_perf_state].control); > + perf->state = next_perf_state; > + return next_freq; > +}
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