kernel: fix yielding between tasks with same deadline

jharris-intel · carlescufi · commit 3330ab12d85c · 2021-02-27T10:25:47.000+01:00
Previously two tasks with the same deadline and priority would
always have `z_is_t1_higher_prio_than_t2` `true` in both directions.

This is logically inconsistent, and results in `k_yield` not actually
yielding between identical threads.

Signed-off-by: James Harris &lt;james.harris@intel.com&gt;
diff --git a/kernel/sched.c b/kernel/sched.c
@@ -100,7 +100,7 @@ bool z_is_t1_higher_prio_than_t2(struct k_thread *thread_1,
 		int32_t d1 = thread_1->base.prio_deadline;
 		int32_t d2 = thread_2->base.prio_deadline;
 
-		return (d2 - d1) >= 0;
+		return (d2 - d1) > 0;
 	}
 #endif
 

Original file line number	Diff line number	Diff line change
`@@ -100,7 +100,7 @@ bool z_is_t1_higher_prio_than_t2(struct k_thread *thread_1,`
`100`	`100`	`int32_t d1 = thread_1->base.prio_deadline;`
`101`	`101`	`int32_t d2 = thread_2->base.prio_deadline;`
`102`	`102`
`103`		`- return (d2 - d1) >= 0;`
	`103`	`+ return (d2 - d1) > 0;`
`104`	`104`	`}`
`105`	`105`	`#endif`
`106`	`106`