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Groups > linux.kernel > #1371447

[PATCH v3 2/6] sched/fair: Remove SCHED_LOAD_SHIFT and SCHED_LOAD_SCALE

From Yuyang Du <yuyang.du@intel.com>
Newsgroups linux.kernel
Subject [PATCH v3 2/6] sched/fair: Remove SCHED_LOAD_SHIFT and SCHED_LOAD_SCALE
Date 2016-04-05 14:00 +0200
Message-ID <rkxOk-2K6-45@gated-at.bofh.it> (permalink)
References <rkxOi-2K6-11@gated-at.bofh.it>
Organization linux.* mail to news gateway

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After cleaning up the sched metrics, these two definitions that cause
ambiguity are not needed any more. Use NICE_0_LOAD_SHIFT and NICE_0_LOAD
instead (the names suggest clearly who they are).

Suggested-by: Ben Segall <bsegall@google.com>
Signed-off-by: Yuyang Du <yuyang.du@intel.com>
---
 kernel/sched/fair.c  |  4 ++--
 kernel/sched/sched.h | 22 +++++++++++-----------
 2 files changed, 13 insertions(+), 13 deletions(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 88ab334..aca96d7 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -719,7 +719,7 @@ void post_init_entity_util_avg(struct sched_entity *se)
 {
 	struct cfs_rq *cfs_rq = cfs_rq_of(se);
 	struct sched_avg *sa = &se->avg;
-	long cap = (long)(scale_load_down(SCHED_LOAD_SCALE) - cfs_rq->avg.util_avg) / 2;
+	long cap = (long)(SCHED_CAPACITY_SCALE - cfs_rq->avg.util_avg) / 2;
 
 	if (cap > 0) {
 		if (cfs_rq->avg.util_avg != 0) {
@@ -6954,7 +6954,7 @@ static inline void calculate_imbalance(struct lb_env *env, struct sd_lb_stats *s
 	if (busiest->group_type == group_overloaded &&
 	    local->group_type   == group_overloaded) {
 		load_above_capacity = busiest->sum_nr_running *
-					SCHED_LOAD_SCALE;
+				      scale_load_down(NICE_0_LOAD);
 		if (load_above_capacity > busiest->group_capacity)
 			load_above_capacity -= busiest->group_capacity;
 		else
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index 03ce2de..6aafe6c 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -54,25 +54,25 @@ static inline void update_cpu_load_active(struct rq *this_rq) { }
  * increased costs.
  */
 #if 0 /* BITS_PER_LONG > 32 -- currently broken: it increases power usage under light load  */
-# define SCHED_LOAD_SHIFT	(SCHED_FIXEDPOINT_SHIFT + SCHED_FIXEDPOINT_SHIFT)
+# define NICE_0_LOAD_SHIFT	(SCHED_FIXEDPOINT_SHIFT + SCHED_FIXEDPOINT_SHIFT)
 # define scale_load(w)		((w) << SCHED_FIXEDPOINT_SHIFT)
 # define scale_load_down(w)	((w) >> SCHED_FIXEDPOINT_SHIFT)
 #else
-# define SCHED_LOAD_SHIFT	(SCHED_FIXEDPOINT_SHIFT)
+# define NICE_0_LOAD_SHIFT	(SCHED_FIXEDPOINT_SHIFT)
 # define scale_load(w)		(w)
 # define scale_load_down(w)	(w)
 #endif
 
-#define SCHED_LOAD_SCALE	(1L << SCHED_LOAD_SHIFT)
-
 /*
- * NICE_0's weight (visible to user) and its load (invisible to user) have
- * independent ranges, but they should be well calibrated. We use scale_load()
- * and scale_load_down(w) to convert between them, the following must be true:
- * scale_load(sched_prio_to_weight[20]) == NICE_0_LOAD
+ * Task weight (visible to user) and its load (invisible to user) have
+ * independent resolution, but they should be well calibrated. We use
+ * scale_load() and scale_load_down(w) to convert between them. The
+ * following must be true:
+ *
+ *  scale_load(sched_prio_to_weight[USER_PRIO(NICE_TO_PRIO(0))]) == NICE_0_LOAD
+ *
  */
-#define NICE_0_LOAD		SCHED_LOAD_SCALE
-#define NICE_0_SHIFT		SCHED_LOAD_SHIFT
+#define NICE_0_LOAD		(1L << NICE_0_LOAD_SHIFT)
 
 /*
  * Single value that decides SCHED_DEADLINE internal math precision.
@@ -859,7 +859,7 @@ DECLARE_PER_CPU(struct sched_domain *, sd_asym);
 struct sched_group_capacity {
 	atomic_t ref;
 	/*
-	 * CPU capacity of this group, SCHED_LOAD_SCALE being max capacity
+	 * CPU capacity of this group, SCHED_CAPACITY_SCALE being max capacity
 	 * for a single CPU.
 	 */
 	unsigned int capacity;
-- 
2.1.4

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Thread

[PATCH v3 0/6] sched/fair: Clean up sched metric definitions Yuyang Du <yuyang.du@intel.com> - 2016-04-05 14:00 +0200
  [PATCH v3 1/6] sched/fair: Generalize the load/util averages resolution definition Yuyang Du <yuyang.du@intel.com> - 2016-04-05 14:00 +0200
  [PATCH v3 2/6] sched/fair: Remove SCHED_LOAD_SHIFT and SCHED_LOAD_SCALE Yuyang Du <yuyang.du@intel.com> - 2016-04-05 14:00 +0200
  [PATCH v3 3/6] sched/fair: Add introduction to the sched load avg metrics Yuyang Du <yuyang.du@intel.com> - 2016-04-05 14:00 +0200

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