* (default: 20ms, units: nanoseconds)
*
* NOTE: this latency value is not the same as the concept of
- * 'timeslice length' - timeslices in CFS are of variable length.
- * (to see the precise effective timeslice length of your workload,
- * run vmstat and monitor the context-switches field)
+ * 'timeslice length' - timeslices in CFS are of variable length
+ * and have no persistent notion like in traditional, time-slice
+ * based scheduling concepts.
*
- * On SMP systems the value of this is multiplied by the log2 of the
- * number of CPUs. (i.e. factor 2x on 2-way systems, 3x on 4-way
- * systems, 4x on 8-way systems, 5x on 16-way systems, etc.)
- * Targeted preemption latency for CPU-bound tasks:
+ * (to see the precise effective timeslice length of your workload,
+ * run vmstat and monitor the context-switches (cs) field)
*/
const_debug unsigned int sysctl_sched_latency = 20000000ULL;
*/
const_debug unsigned int sysctl_sched_wakeup_granularity = 10000000UL;
+const_debug unsigned int sysctl_sched_migration_cost = 500000UL;
+
/**************************************************************
* CFS operations on generic schedulable entities:
*/
se->exec_start = rq_of(cfs_rq)->clock;
}
-/*
- * We are descheduling a task - update its stats:
- */
-static inline void
-update_stats_curr_end(struct cfs_rq *cfs_rq, struct sched_entity *se)
-{
- se->exec_start = 0;
-}
-
/**************************************************
* Scheduling class queueing methods:
*/
if (prev->on_rq)
update_curr(cfs_rq);
- update_stats_curr_end(cfs_rq, prev);
-
check_spread(cfs_rq, prev);
if (prev->on_rq) {
update_stats_wait_start(cfs_rq, prev);
resched_task(curr);
return;
}
+ /*
+ * Batch tasks do not preempt (their preemption is driven by
+ * the tick):
+ */
+ if (unlikely(p->policy == SCHED_BATCH))
+ return;
if (sched_feat(WAKEUP_PREEMPT)) {
while (!is_same_group(se, pse)) {