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kernel: support for more than 32 total priorities

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In addition to more priorities taking more memory to host them, finding
the next thread to run when it is not cached is slower since each extra
set of 32 priorities maps to a loop iteration. That loop is remove
entirely when the number of priorities is less than 32 (31 + the idle
thread).

Fixes ZEP-1303.

Change-Id: I3205df90d379a0f4456ff1d7f1aaa67ad2cddf15
Signed-off-by: Benjamin Walsh <benjamin.walsh@windriver.com>
This commit is contained in:
Benjamin Walsh 2016-11-18 15:35:05 -05:00 • committed by Anas Nashif
commit 358a53cb2f
5 changed files with 48 additions and 14 deletions
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27
kernel/unified/include/ksched.h
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@ -167,17 +167,32 @@ static inline int _get_ready_q_q_index(int prio)
return prio + CONFIG_NUM_COOP_PRIORITIES;
}
#if (K_NUM_PRIORITIES > 32)
#error not supported yet
#endif
/* find out the currently highest priority where a thread is ready to run */
/* interrupts must be locked */
static inline int _get_highest_ready_prio(void)
{
uint32_t ready = _ready_q.prio_bmap[0];
int bitmap = 0;
uint32_t ready_range;
return find_lsb_set(ready) - 1 - CONFIG_NUM_COOP_PRIORITIES;
#if (K_NUM_PRIORITIES <= 32)
ready_range = _ready_q.prio_bmap[0];
#else
for (;; bitmap++) {
__ASSERT(bitmap < K_NUM_PRIO_BITMAPS, "prio out-of-range\n");
if (_ready_q.prio_bmap[bitmap]) {
ready_range = _ready_q.prio_bmap[bitmap];
break;
}
}
#endif
int abs_prio = (find_lsb_set(ready_range) - 1) + (bitmap << 5);
__ASSERT(abs_prio < K_NUM_PRIORITIES, "prio out-of-range\n");
return abs_prio - CONFIG_NUM_COOP_PRIORITIES;
}
/*