Hi Patrick,
On 5/16/19 2:22 PM, Patrick Bellasi wrote:
On 16-May 14:01, Quentin Perret wrote:
On Thursday 16 May 2019 at 13:42:00 (+0100), Patrick Bellasi wrote:
+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;
^^^^
... end here we should probably better use SCHED_CAPACITY_SCALE
instead of hard-coding in values, isn't it?
I'm not sure to agree. This isn't part of the scheduler per se, and the
cost thing isn't in units of capacity, but in units of power, so I don't
think SCHED_CAPACITY_SCALE is correct here.
Right, I get the units do not match and it would not be elegant to use
it here...
But I agree these hard coded values (that one, and the 512 in one of the
following patches) could use some motivation :-)
... ultimately SCHED_CAPACITY_SCALE is just SCHED_FIXEDPOINT_SCALE,
which is adimensional. Perhaps we should use that or yet another alias
for the same.
Would it be a good idea to use SCHED_FIXEDPOINT_SCALE in energy.c ?
Since it's not part of the scheduler, maybe there is a scale covering a wider
scope,
or we can introduce a similar ENERGY_FIXEDPOINT_SCALE in energy_model.h.
Thanks,
Quentin
Thanks,
Douglas
