diff options
Diffstat (limited to 'kernel/power')
| -rw-r--r-- | kernel/power/energy_model.c | 23 |
1 files changed, 8 insertions, 15 deletions
diff --git a/kernel/power/energy_model.c b/kernel/power/energy_model.c index a332ccd829e2..97e62469a6b3 100644 --- a/kernel/power/energy_model.c +++ b/kernel/power/energy_model.c @@ -107,8 +107,7 @@ static void em_debug_remove_pd(struct device *dev) {} static int em_create_perf_table(struct device *dev, struct em_perf_domain *pd, int nr_states, struct em_data_callback *cb) { - unsigned long opp_eff, prev_opp_eff = ULONG_MAX; - unsigned long power, freq, prev_freq = 0; + unsigned long power, freq, prev_freq = 0, prev_cost = ULONG_MAX; struct em_perf_state *table; int i, ret; u64 fmax; @@ -153,27 +152,21 @@ static int em_create_perf_table(struct device *dev, struct em_perf_domain *pd, table[i].power = power; table[i].frequency = prev_freq = freq; - - /* - * The hertz/watts efficiency ratio should decrease as the - * frequency grows on sane platforms. But this isn't always - * true in practice so warn the user if a higher OPP is more - * power efficient than a lower one. - */ - opp_eff = freq / power; - if (opp_eff >= prev_opp_eff) - dev_dbg(dev, "EM: hertz/watts ratio non-monotonically decreasing: em_perf_state %d >= em_perf_state%d\n", - i, i - 1); - prev_opp_eff = opp_eff; } /* Compute the cost of each performance state. */ fmax = (u64) table[nr_states - 1].frequency; - for (i = 0; i < nr_states; i++) { + for (i = nr_states - 1; i >= 0; i--) { unsigned long power_res = em_scale_power(table[i].power); table[i].cost = div64_u64(fmax * power_res, table[i].frequency); + if (table[i].cost >= prev_cost) { + dev_dbg(dev, "EM: OPP:%lu is inefficient\n", + table[i].frequency); + } else { + prev_cost = table[i].cost; + } } pd->table = table; |