[PATCH 4/9] cpufreq: governor: Clean up load-related computations

From: Rafael J. Wysocki
Date: Sun Feb 14 2016 - 20:21:21 EST


From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>

Clean up some load-related computations in dbs_check_cpu() and
cpufreq_governor_start() to get rid of unnecessary operations and
type casts and make the code easier to read.

No functional changes.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
---
drivers/cpufreq/cpufreq_governor.c | 24 ++++++++++--------------
1 file changed, 10 insertions(+), 14 deletions(-)

Index: linux-pm/drivers/cpufreq/cpufreq_governor.c
===================================================================
--- linux-pm.orig/drivers/cpufreq/cpufreq_governor.c
+++ linux-pm/drivers/cpufreq/cpufreq_governor.c
@@ -186,16 +186,15 @@ void dbs_check_cpu(struct cpufreq_policy
io_busy = od_tuners->io_is_busy;
cur_idle_time = get_cpu_idle_time(j, &cur_wall_time, io_busy);

- wall_time = (unsigned int)
- (cur_wall_time - j_cdbs->prev_cpu_wall);
+ wall_time = cur_wall_time - j_cdbs->prev_cpu_wall;
j_cdbs->prev_cpu_wall = cur_wall_time;

- if (cur_idle_time < j_cdbs->prev_cpu_idle)
- cur_idle_time = j_cdbs->prev_cpu_idle;
-
- idle_time = (unsigned int)
- (cur_idle_time - j_cdbs->prev_cpu_idle);
- j_cdbs->prev_cpu_idle = cur_idle_time;
+ if (cur_idle_time <= j_cdbs->prev_cpu_idle) {
+ idle_time = 0;
+ } else {
+ idle_time = cur_idle_time - j_cdbs->prev_cpu_idle;
+ j_cdbs->prev_cpu_idle = cur_idle_time;
+ }

if (ignore_nice) {
u64 cur_nice = kcpustat_cpu(j).cpustat[CPUTIME_NICE];
@@ -571,13 +570,10 @@ static int cpufreq_governor_start(struct
struct cpu_dbs_info *j_cdbs = gov->get_cpu_cdbs(j);
unsigned int prev_load;

- j_cdbs->prev_cpu_idle =
- get_cpu_idle_time(j, &j_cdbs->prev_cpu_wall, io_busy);
+ j_cdbs->prev_cpu_idle = get_cpu_idle_time(j, &j_cdbs->prev_cpu_wall, io_busy);

- prev_load = (unsigned int)(j_cdbs->prev_cpu_wall -
- j_cdbs->prev_cpu_idle);
- j_cdbs->prev_load = 100 * prev_load /
- (unsigned int)j_cdbs->prev_cpu_wall;
+ prev_load = j_cdbs->prev_cpu_wall - j_cdbs->prev_cpu_idle;
+ j_cdbs->prev_load = 100 * prev_load / j_cdbs->prev_cpu_wall;

if (ignore_nice)
j_cdbs->prev_cpu_nice = kcpustat_cpu(j).cpustat[CPUTIME_NICE];