lkml.org 
[lkml]   [2022]   [Aug]   [2]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[tip: sched/core] sched/deadline: Use sched_dl_entity's dl_density in dl_task_fits_capacity()
The following commit has been merged into the sched/core branch of tip:

Commit-ID: b3f53daacc74c0ca0922e14a8cb793cb2db4c6d1
Gitweb: https://git.kernel.org/tip/b3f53daacc74c0ca0922e14a8cb793cb2db4c6d1
Author: Dietmar Eggemann <dietmar.eggemann@arm.com>
AuthorDate: Fri, 29 Jul 2022 13:13:05 +02:00
Committer: Ingo Molnar <mingo@kernel.org>
CommitterDate: Tue, 02 Aug 2022 12:32:46 +02:00

sched/deadline: Use sched_dl_entity's dl_density in dl_task_fits_capacity()

Save a multiplication in dl_task_fits_capacity() by using already
maintained per-sched_dl_entity (i.e. per-task) `dl_runtime/dl_deadline`
(dl_density).

cap_scale(dl_deadline, cap) >= dl_runtime

dl_deadline * cap >> SCHED_CAPACITY_SHIFT >= dl_runtime

cap >= dl_runtime << SCHED_CAPACITY_SHIFT / dl_deadline

cap >= (dl_runtime << BW_SHIFT / dl_deadline) >>
BW_SHIFT - SCHED_CAPACITY_SHIFT

cap >= dl_density >> BW_SHIFT - SCHED_CAPACITY_SHIFT

__sched_setscheduler()->__checkparam_dl() ensures that the 2 corner
cases (if conditions) `runtime == RUNTIME_INF (-1)` and `period == 0`
of to_ratio(deadline, runtime) are not met when setting dl_density in
__sched_setscheduler()-> __setscheduler_params()->__setparam_dl().

Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20220729111305.1275158-4-dietmar.eggemann@arm.com
---
kernel/sched/sched.h | 30 +++++++++++++++---------------
1 file changed, 15 insertions(+), 15 deletions(-)

diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index 86fc360..3ccd35c 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -320,21 +320,6 @@ struct dl_bw {
u64 total_bw;
};

-/*
- * Verify the fitness of task @p to run on @cpu taking into account the
- * CPU original capacity and the runtime/deadline ratio of the task.
- *
- * The function will return true if the CPU original capacity of the
- * @cpu scaled by SCHED_CAPACITY_SCALE >= runtime/deadline ratio of the
- * task and false otherwise.
- */
-static inline bool dl_task_fits_capacity(struct task_struct *p, int cpu)
-{
- unsigned long cap = arch_scale_cpu_capacity(cpu);
-
- return cap_scale(p->dl.dl_deadline, cap) >= p->dl.dl_runtime;
-}
-
extern void init_dl_bw(struct dl_bw *dl_b);
extern int sched_dl_global_validate(void);
extern void sched_dl_do_global(void);
@@ -2899,6 +2884,21 @@ unsigned long effective_cpu_util(int cpu, unsigned long util_cfs,
enum cpu_util_type type,
struct task_struct *p);

+/*
+ * Verify the fitness of task @p to run on @cpu taking into account the
+ * CPU original capacity and the runtime/deadline ratio of the task.
+ *
+ * The function will return true if the original capacity of @cpu is
+ * greater than or equal to task's deadline density right shifted by
+ * (BW_SHIFT - SCHED_CAPACITY_SHIFT) and false otherwise.
+ */
+static inline bool dl_task_fits_capacity(struct task_struct *p, int cpu)
+{
+ unsigned long cap = arch_scale_cpu_capacity(cpu);
+
+ return cap >= p->dl.dl_density >> (BW_SHIFT - SCHED_CAPACITY_SHIFT);
+}
+
static inline unsigned long cpu_bw_dl(struct rq *rq)
{
return (rq->dl.running_bw * SCHED_CAPACITY_SCALE) >> BW_SHIFT;
\
 
 \ /
  Last update: 2022-08-02 13:03    [W:0.037 / U:1.240 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site