Messages in this thread Patch in this message | | | From | douglas.raillard@arm ... | Subject | [RFC PATCH 1/7] PM: Introduce em_pd_get_higher_freq() | Date | Wed, 8 May 2019 18:42:55 +0100 |
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From: Douglas RAILLARD <douglas.raillard@arm.com>
em_pd_get_higher_freq() returns a frequency greater or equal to the provided one while taking into account a given cost margin. It also skips inefficient OPPs that have a higher cost than another one with a higher frequency.
Signed-off-by: Douglas RAILLARD <douglas.raillard@arm.com> --- include/linux/energy_model.h | 48 ++++++++++++++++++++++++++++++++++++ 1 file changed, 48 insertions(+)
diff --git a/include/linux/energy_model.h b/include/linux/energy_model.h index aa027f7bcb3e..797b4e0f758c 100644 --- a/include/linux/energy_model.h +++ b/include/linux/energy_model.h @@ -159,6 +159,48 @@ static inline int em_pd_nr_cap_states(struct em_perf_domain *pd) return pd->nr_cap_states; } +/** + * em_pd_get_higher_freq() - Get the highest frequency that does not exceed the + * given cost margin compared to min_freq + * @pd : performance domain for which this must be done + * @min_freq : minimum frequency to return + * @cost_margin : allowed margin compared to min_freq, as a per-1024 value. + * + * Return: the chosen frequency, guaranteed to be at least as high as min_freq. + */ +static inline unsigned long em_pd_get_higher_freq(struct em_perf_domain *pd, + unsigned long min_freq, unsigned long cost_margin) +{ + unsigned long max_cost = 0; + struct em_cap_state *cs; + int i; + + if (!pd) + return min_freq; + + /* Compute the maximum allowed cost */ + for (i = 0; i < pd->nr_cap_states; i++) { + cs = &pd->table[i]; + if (cs->frequency >= min_freq) { + max_cost = cs->cost + (cs->cost * cost_margin) / 1024; + break; + } + } + + /* Find the highest frequency that will not exceed the cost margin */ + for (i = pd->nr_cap_states-1; i >= 0; i--) { + cs = &pd->table[i]; + if (cs->cost <= max_cost) + return cs->frequency; + } + + /* + * We should normally never reach here, unless min_freq was higher than + * the highest available frequency, which is not expected to happen. + */ + return min_freq; +} + #else struct em_perf_domain {}; struct em_data_callback {}; @@ -182,6 +224,12 @@ static inline int em_pd_nr_cap_states(struct em_perf_domain *pd) { return 0; } + +static inline unsigned long em_pd_get_higher_freq(struct em_perf_domain *pd, + unsigned long min_freq, unsigned long cost_margin) +{ + return min_freq; +} #endif #endif -- 2.21.0
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