[LITMUS^RT] Questions on data struct bheap and rt_domain_t

[Hang Su]

Hi all:

I have a couple of questions as described as followings:

1. struct bheap is binary heap and struct bheap_node represents each heap
node in a heap, right ? A traditionally binary heap node could have up to
two children, left one and right one. In struct bheap_node, I see its has
next and child. Which is the corresponding left child and right child ? Or,
child and sibling representation is used, so that a bheap_node only
maintain its left child and its sibling. And degree represents how many
children it has or what ?  In struct bheap, there are head and min. If it
was a minimum heap, head and min should points to the same bheap_node,
which is the heap root, after each bheap operation like insertion and
deletion. When does they differs ?

2. In rt_domian.h, there is a struct rt_domain_t. What is the difference
between release_queue and tobe_released. From the comments, they are all
related to release queue. But i am a little bit confused about them. Inside
requeue function in sched_gsn_edf.c, a task is linked in tobe_released
instead of release_queue through calling add_release(&gsnedf,task), if it
has not been released . If an example could be shown, it is pretty much
clear for me. For example, we have a task set with two tasks, T1(c1,p1) =
(3,5)  and T2(c2,p2)=(2,6). This task set will be scheduled on one
processor by EDF. At time 0, both of their jobs are released. And the
release_queue.slot[5] ,  release_queue.slot[10], ..., release_queue.slot[
min( 5*i, RELEASE_QUEUE_SLOTS) ], maintain jobs from T1, which will be
released within window-sized RELEASE_QUEUE_SLOTS.  is that right ?


Thanks.
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