Re: [PATCH v5 05/23] PM: EM: Refactor a new function em_compute_costs()

Qais Yousef
2023-12-17T17:58:48Z

On 11/29/23 11:08, Lukasz Luba wrote:
> Refactor a dedicated function which will be easier to maintain and re-use
> in future. The upcoming changes for the modifiable EM perf_state table
> will use it (instead of duplicating the code).

nit: What is being refactored? Looks like you took em_compute_cost() out of
em_create_perf_table().

Cheers

--
Qais Yousef

>
> This change is not expected to alter the general functionality.
>
> Signed-off-by: Lukasz Luba <lukasz.luba@arm.com>
> ---
> kernel/power/energy_model.c | 72 ++++++++++++++++++++++---------------
> 1 file changed, 43 insertions(+), 29 deletions(-)
>
> diff --git a/kernel/power/energy_model.c b/kernel/power/energy_model.c
> index aa7c89f9e115..3bea930410c6 100644
> --- a/kernel/power/energy_model.c
> +++ b/kernel/power/energy_model.c
> @@ -103,14 +103,52 @@ static void em_debug_create_pd(struct device *dev) {}
> static void em_debug_remove_pd(struct device *dev) {}
> #endif
>
> +static int em_compute_costs(struct device *dev, struct em_perf_state *table,
> + struct em_data_callback *cb, int nr_states,
> + unsigned long flags)
> +{
> + unsigned long prev_cost = ULONG_MAX;
> + u64 fmax;
> + int i, ret;
> +
> + /* Compute the cost of each performance state. */
> + fmax = (u64) table[nr_states - 1].frequency;
> + for (i = nr_states - 1; i >= 0; i--) {
> + unsigned long power_res, cost;
> +
> + if (flags & EM_PERF_DOMAIN_ARTIFICIAL) {
> + ret = cb->get_cost(dev, table[i].frequency, &cost);
> + if (ret || !cost || cost > EM_MAX_POWER) {
> + dev_err(dev, "EM: invalid cost %lu %d\n",
> + cost, ret);
> + return -EINVAL;
> + }
> + } else {
> + power_res = table[i].power;
> + cost = div64_u64(fmax * power_res, table[i].frequency);
> + }
> +
> + table[i].cost = cost;
> +
> + if (table[i].cost >= prev_cost) {
> + table[i].flags = EM_PERF_STATE_INEFFICIENT;
> + dev_dbg(dev, "EM: OPP:%lu is inefficient\n",
> + table[i].frequency);
> + } else {
> + prev_cost = table[i].cost;
> + }
> + }
> +
> + return 0;
> +}
> +
> static int em_create_perf_table(struct device *dev, struct em_perf_domain *pd,
> int nr_states, struct em_data_callback *cb,
> unsigned long flags)
> {
> - unsigned long power, freq, prev_freq = 0, prev_cost = ULONG_MAX;
> + unsigned long power, freq, prev_freq = 0;
> struct em_perf_state *table;
> int i, ret;
> - u64 fmax;
>
> table = kcalloc(nr_states, sizeof(*table), GFP_KERNEL);
> if (!table)
> @@ -154,33 +192,9 @@ static int em_create_perf_table(struct device *dev, struct em_perf_domain *pd,
> table[i].frequency = prev_freq = freq;
> }
>
> - /* Compute the cost of each performance state. */
> - fmax = (u64) table[nr_states - 1].frequency;
> - for (i = nr_states - 1; i >= 0; i--) {
> - unsigned long power_res, cost;
> -
> - if (flags & EM_PERF_DOMAIN_ARTIFICIAL) {
> - ret = cb->get_cost(dev, table[i].frequency, &cost);
> - if (ret || !cost || cost > EM_MAX_POWER) {
> - dev_err(dev, "EM: invalid cost %lu %d\n",
> - cost, ret);
> - goto free_ps_table;
> - }
> - } else {
> - power_res = table[i].power;
> - cost = div64_u64(fmax * power_res, table[i].frequency);
> - }
> -
> - table[i].cost = cost;
> -
> - if (table[i].cost >= prev_cost) {
> - table[i].flags = EM_PERF_STATE_INEFFICIENT;
> - dev_dbg(dev, "EM: OPP:%lu is inefficient\n",
> - table[i].frequency);
> - } else {
> - prev_cost = table[i].cost;
> - }
> - }
> + ret = em_compute_costs(dev, table, cb, nr_states, flags);
> + if (ret)
> + goto free_ps_table;
>
> pd->table = table;
> pd->nr_perf_states = nr_states;
> --
> 2.25.1
>