Re: [PATCH] sched/uclamp: New sysctl to tweak boost for uclamp tasks

From: Chitti Babu Theegala
Date: Wed Feb 09 2022 - 09:52:58 EST



Sorry, please ignore this patch. It was wrongly uploaded here.
Will pursue this to right tree.

On 2/9/2022 7:29 PM, Vincent Donnefort wrote:
[...]

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 634d571e39d77..55019eb9c83c5 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -1269,6 +1269,14 @@ unsigned int sysctl_sched_uclamp_util_max = SCHED_CAPACITY_SCALE;
*/
unsigned int sysctl_sched_uclamp_util_min_rt_default = SCHED_CAPACITY_SCALE;
+/* UCLAMP_MIN knob clamps the util_value within uclamp_min & max. By default,
+ * these uclamped tasks are also boosted to bigger cores which can impact power.
+ *
+ * This knob provides an option to turn-off 'boosting to gold cores' and
+ * just restrict to 'clamping util value' job.
+ */
+unsigned int sysctl_sched_uclamp_util_min_to_boost = 1;
+
/* All clamps are required to be less or equal than these values */
static struct uclamp_se uclamp_default[UCLAMP_CNT];
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 7cd316793f4e3..44adcbfa9eb32 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -6829,7 +6829,7 @@ static int find_energy_efficient_cpu(struct task_struct *p, int prev_cpu, int sy
goto unlock;
latency_sensitive = uclamp_latency_sensitive(p);

I don't think this is the right tree.

Thanks ! I just noticed it :-(



- boosted = uclamp_boosted(p);
+ boosted = sysctl_sched_uclamp_util_min_to_boost && uclamp_boosted(p);
target_cap = boosted ? 0 : ULONG_MAX;
for (; pd; pd = pd->next) {
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 8f196ed2ec065..6463d60fed84e 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -1882,6 +1882,15 @@ static struct ctl_table kern_table[] = {
.mode = 0644,
.proc_handler = sysctl_sched_uclamp_handler,
},
+ {
+ .procname = "sched_util_clamp_min_to_boost",
+ .data = &sysctl_sched_uclamp_util_min_to_boost,
+ .maxlen = sizeof(unsigned int),
+ .mode = 0644,
+ .proc_handler = proc_dointvec_minmax,
+ .extra1 = SYSCTL_ZERO,
+ .extra2 = SYSCTL_ONE,
+ },
#endif
#ifdef CONFIG_SCHED_AUTOGROUP
{
--
2.17.1