Kuan-Wei Chiu <visitor...@gmail.com> writes: > When constructing a heap, heapify operations are required on all > non-leaf nodes. Thus, determining the index of the first non-leaf node > is crucial. In a heap, the left child's index of node i is 2 * i + 1 > and the right child's index is 2 * i + 2. Node CAKE_MAX_TINS * > CAKE_QUEUES / 2 has its left and right children at indexes > CAKE_MAX_TINS * CAKE_QUEUES + 1 and CAKE_MAX_TINS * CAKE_QUEUES + 2, > respectively, which are beyond the heap's range, indicating it as a > leaf node. Conversely, node CAKE_MAX_TINS * CAKE_QUEUES / 2 - 1 has a > left child at index CAKE_MAX_TINS * CAKE_QUEUES - 1, confirming its > non-leaf status. The loop should start from it since it's not a leaf > node. > > By starting the loop from CAKE_MAX_TINS * CAKE_QUEUES / 2 - 1, we > minimize function calls and branch condition evaluations. This > adjustment theoretically reduces two function calls (one for > cake_heapify() and another for cake_heap_get_backlog()) and five branch > evaluations (one for iterating all non-leaf nodes, one within > cake_heapify()'s while loop, and three more within the while loop > with if conditions). > > Signed-off-by: Kuan-Wei Chiu <visitor...@gmail.com>
Acked-by: Toke Høiland-Jørgensen <t...@toke.dk> _______________________________________________ Cake mailing list Cake@lists.bufferbloat.net https://lists.bufferbloat.net/listinfo/cake
