This is the mail archive of the ecos-discuss@sources.redhat.com mailing list for the eCos project.
Index Nav: | [Date Index] [Subject Index] [Author Index] [Thread Index] | |
---|---|---|
Message Nav: | [Date Prev] [Date Next] | [Thread Prev] [Thread Next] |
Other format: | [Raw text] |
TomChen <chenqy_79@163.com> writes:Consider such a scenario, we enqueue three threads with priority 3, 5, 4 respectively into an empty queue in the order as shown. According to the originall code, we will get the result:
Hi All,
Kernel package src/sched/mlqueue.cxx in function Cyg_ThreadQueue_Implementation::enqueue(Cyg_Thread *thread) ,
When there is more than one thread in the queue and the priority is neither higer than the head nor lower than the tail, we have to search the queue to find the place. The code for this is:
Cyg_Thread *qtmp = get_tail(); while ( thread->priority > qtmp->priority) qtmp = qtmp->get_prev(); qtmp->append( thread );
I think this should be:
Cyg_Thread *qtmp = get_tail();
while ( thread->priority *<* qtmp->priority)
qtmp = qtmp->get_prev();
qtmp->append( thread );
I believe the original code it correct.
Remember that the priorities go from 0=highest to 31=lowest. So the loop spins while the thread priorities are numerically greater than the one we want to insert. Once we find one that is less than or equal we break out and install the new thread just after it.
if( thread->priority > get_tail()->priority ) { // We are lower priority than any thread in the queue, // go in at the end. add_tail( thread ); } So, I think this is a bug.
-- Before posting, please read the FAQ: http://ecos.sourceware.org/fom/ecos and search the list archive: http://ecos.sourceware.org/ml/ecos-discuss
Index Nav: | [Date Index] [Subject Index] [Author Index] [Thread Index] | |
---|---|---|
Message Nav: | [Date Prev] [Date Next] | [Thread Prev] [Thread Next] |