wangzhi16
d9d438f205
TESTCASE: On CPU1, create a thread with affinity CPU1. Since the priority is the same as the current thread, the newly created thread has not yet been executed. Then, call sched_setaffinity() to reset the affinity of the new thread to CPU0, and then call join to wait for the new thread to finish executing. At this point, the current system is found to be stuck. However, when I create a new thread on CPU0 and set its affinity to CPU1, it can be successfully executed. REASON: There is a logical judgment in the nxsched_set_affinity function called by sched_setaffinity at the bottom layer. When the affinity is changed, whether nxsched_set_priority() needs to be called to modify the task queue of each CPU. The judgment condition here is "(tcb->affinity & (1 << tcb->cpu)) == 0". If it is for a running program, this is no problem, because tcb->cpu will be assigned the correct value when the task is activated. However, for a program that has not yet run, the value of tcb->cpu is not valid, and the default value is 0. At this time, if you want to change the affinity from CPU1 to CPU0, affinity is 1, tcb->cpu is 0, then the expression (tcb->affinity & (1 << tcb->cpu)) = 1, which does not meet the judgment condition, so the nxsched_set_priority() function is not called. Therefore, it is necessary to set a CPU value that can run for the ready task. Signed-off-by: wangzhi16 <wangzhi16@xiaomi.com>
Apache NuttX is a real-time operating system (RTOS) with an emphasis on standards compliance and small footprint. Scalable from 8-bit to 64-bit microcontroller environments, the primary governing standards in NuttX are POSIX and ANSI standards. Additional standard APIs from Unix and other common RTOSs (such as VxWorks) are adopted for functionality not available under these standards, or for functionality that is not appropriate for deeply-embedded environments (such as fork()).
For brevity, many parts of the documentation will refer to Apache NuttX as simply NuttX.
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