kernel: do not call swap if next ready thread is current thread
Check if next ready thread is same as current thread before calling
z_swap.
This avoids calling swap to just go back to the original thread.
Original code: thread 0x20000118 switches out and then in again...
>> 0x20000118 gives semaphore(signal): 0x20000104 (count: 0)
>> thread ready: 0x20000118
>> 0x20000118 switched out
>> 0x20000118 switched in
>> end call to k_sem_give
>> 0x20000118 takes semaphore(wait): 0x200000f4 (count: 0)
>> thread pend: 0x20000118
>> 0x20000118 switched out
>> 0x200001d0 switched in
with this patch:
>> 0x200001d0 gives semaphore(signal): 0x200000f4 (count: 0)
>> thread ready: 0x200001d0
>> end call to k_sem_give
>> 0x200001d0 takes semaphore(wait): 0x20000104 (count: 0)
>> thread pend: 0x200001d0
>> 0x200001d0 switched out
>> 0x20000118 switched in
>> end call to k_sem_take
The above is output from tracing with a custom format used for
debugging.
Signed-off-by: Anas Nashif <anas.nashif@intel.com>
1 file changed
