forked from haiwan/sledge
Sean McBride
5 years ago
parent
d14af73c30
commit
34d91cfa21
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Subproject commit 28f3c35c215ffbe0241685901338fad484660454
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#ifndef PRIORITY_QUEUE_H
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#define PRIORITY_QUEUE_H
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#include <spinlock/fas.h>
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#define MAX 4096
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/**
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* How to get the priority out of the generic element
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* We assume priority is expressed as an unsigned 64-bit integer (i.e. cycles or
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* UNIX time in ms). This is used to maintain a read replica of the highest
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* priority element that can be used to maintain a read replica
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* @param element
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* @returns priority (a u64)
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**/
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typedef unsigned long long int (*priority_queue_get_priority_t)(void *element);
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// We assume that priority is expressed in terms of a 64 bit unsigned integral
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struct priority_queue {
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ck_spinlock_fas_t lock;
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unsigned long long int highest_priority;
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void * items[MAX];
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int first_free;
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priority_queue_get_priority_t get_priority;
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};
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void priority_queue_initialize(struct priority_queue *self, priority_queue_get_priority_t get_priority);
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int priority_queue_enqueue(struct priority_queue *self, void *value);
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void *priority_queue_dequeue(struct priority_queue *self);
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int priority_queue_length(struct priority_queue *self);
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#endif /* PRIORITY_QUEUE_H */
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#ifndef SFRT_SANDBOX_REQUEST_QUEUE_H
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#define SFRT_SANDBOX_REQUEST_QUEUE_H
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#include <sandbox_request.h>
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void sandbox_request_queue_initialize(void);
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int sandbox_request_queue_add(sandbox_request_t *);
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sandbox_request_t *sandbox_request_queue_remove(void);
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#endif /* SFRT_SANDBOX_REQUEST_QUEUE_H */
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Subproject commit 85695f3d5903b1cd5b4030efe50db3b4f5f3c928
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#include <assert.h>
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#include <limits.h>
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#include <stdio.h>
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#include <string.h>
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#include <priority_queue.h>
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/****************************
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* Private Helper Functions *
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****************************/
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/**
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* Adds a value to the end of the binary heap
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* @param self the priority queue
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* @param new_item the value we are adding
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* @return 0 on success. -1 when priority queue is full
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**/
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static inline int
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priority_queue_append(struct priority_queue *self, void *new_item)
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{
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assert(self != NULL);
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if (self->first_free >= MAX) return -1;
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self->items[self->first_free] = new_item;
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self->first_free++;
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return 0;
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}
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/**
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* Shifts an appended value upwards to restore heap structure property
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* @param self the priority queue
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*/
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static inline void
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priority_queue_percolate_up(struct priority_queue *self)
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{
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assert(self != NULL);
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assert(self->get_priority != NULL);
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for (int i = self->first_free - 1;
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i / 2 != 0 && self->get_priority(self->items[i]) < self->get_priority(self->items[i / 2]); i /= 2) {
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void *temp = self->items[i / 2];
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self->items[i / 2] = self->items[i];
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self->items[i] = temp;
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// If percolated to highest priority, update highest priority
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if (i / 2 == 1) self->highest_priority = self->get_priority(self->items[1]);
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}
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}
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/**
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* Returns the index of a node's smallest child
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* @param self the priority queue
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* @param parent_index
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* @returns the index of the smallest child
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*/
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static inline int
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priority_queue_find_smallest_child(struct priority_queue *self, int parent_index)
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{
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assert(self != NULL);
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assert(parent_index >= 1 && parent_index < self->first_free);
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assert(self->get_priority != NULL);
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int left_child_index = 2 * parent_index;
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int right_child_index = 2 * parent_index + 1;
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assert(self->items[left_child_index] != NULL);
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// If we don't have a right child or the left child is smaller, return it
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if (right_child_index == self->first_free) {
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return left_child_index;
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} else if (self->get_priority(self->items[left_child_index])
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< self->get_priority(self->items[right_child_index])) {
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return left_child_index;
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} else {
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// Otherwise, return the right child
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return right_child_index;
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}
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}
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/**
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* Shifts the top of the heap downwards. Used after placing the last value at
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* the top
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* @param self the priority queue
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*/
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static inline void
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priority_queue_percolate_down(struct priority_queue *self)
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{
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assert(self != NULL);
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assert(self->get_priority != NULL);
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int parent_index = 1;
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int left_child_index = 2 * parent_index;
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while (left_child_index >= 2 && left_child_index < self->first_free) {
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int smallest_child_index = priority_queue_find_smallest_child(self, parent_index);
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// Once the parent is equal to or less than its smallest child, break;
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if (self->get_priority(self->items[parent_index])
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<= self->get_priority(self->items[smallest_child_index]))
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break;
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// Otherwise, swap and continue down the tree
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void *temp = self->items[smallest_child_index];
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self->items[smallest_child_index] = self->items[parent_index];
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self->items[parent_index] = temp;
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parent_index = smallest_child_index;
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left_child_index = 2 * parent_index;
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}
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}
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/*********************
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* Public API *
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*********************/
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/**
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* Initialized the Priority Queue Data structure
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* @param self the priority_queue to initialize
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* @param get_priority pointer to a function that returns the priority of an
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*element
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**/
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void
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priority_queue_initialize(struct priority_queue *self, priority_queue_get_priority_t get_priority)
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{
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assert(self != NULL);
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assert(get_priority != NULL);
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memset(self->items, 0, sizeof(void *) * MAX);
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ck_spinlock_fas_init(&self->lock);
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self->first_free = 1;
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self->get_priority = get_priority;
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// We're assuming a min-heap implementation, so set to larget possible value
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self->highest_priority = ULONG_MAX;
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}
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/**
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* @param self the priority_queue
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* @returns the number of elements in the priority queue
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**/
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int
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priority_queue_length(struct priority_queue *self)
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{
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assert(self != NULL);
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return self->first_free - 1;
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}
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/**
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* @param self - the priority queue we want to add to
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* @param value - the value we want to add
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* @returns 0 on success. -1 on full. -2 on unable to take lock
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**/
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int
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priority_queue_enqueue(struct priority_queue *self, void *value)
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{
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assert(self != NULL);
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int rc;
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if (ck_spinlock_fas_trylock(&self->lock) == false) return -2;
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// Start of Critical Section
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if (priority_queue_append(self, value) == 0) {
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if (self->first_free > 2) {
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priority_queue_percolate_up(self);
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} else {
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// If this is the first element we add, update the highest priority
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self->highest_priority = self->get_priority(value);
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}
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rc = 0;
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} else {
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// Priority Queue is full
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rc = -1;
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}
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// End of Critical Section
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ck_spinlock_fas_unlock(&self->lock);
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return rc;
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}
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/**
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* @param self - the priority queue we want to add to
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* @returns The head of the priority queue or NULL when empty
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**/
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void *
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priority_queue_dequeue(struct priority_queue *self)
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{
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assert(self != NULL);
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assert(self->get_priority != NULL);
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// If first_free is 1, we're empty
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if (self->first_free == 1) return NULL;
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if (ck_spinlock_fas_trylock(&self->lock) == false) return NULL;
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// Start of Critical Section
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void *min = self->items[1];
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self->items[1] = self->items[self->first_free - 1];
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self->items[self->first_free - 1] = NULL;
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self->first_free--;
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assert(self->first_free == 1 || self->items[self->first_free - 1] != NULL);
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// Because of 1-based indices, first_free is 2 when there is only one element
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if (self->first_free > 2) priority_queue_percolate_down(self);
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if (self->first_free > 1) {
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self->highest_priority = self->get_priority(self->items[1]);
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} else {
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self->highest_priority = ULONG_MAX;
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}
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ck_spinlock_fas_unlock(&self->lock);
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// End of Critical Section
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return min;
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}
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@ -0,0 +1,137 @@
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#include <sandbox_request_queue.h>
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#include <priority_queue.h>
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enum scheduling_policy
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{
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FIFO,
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PS
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};
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enum scheduling_policy sandbox_request_queue_policy = FIFO;
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// FIFO Globals
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struct deque_sandbox *runtime_global_deque;
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pthread_mutex_t runtime_global_deque_mutex = PTHREAD_MUTEX_INITIALIZER;
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// PS Globals
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struct priority_queue sandbox_request_queue_ps;
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static inline void
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sandbox_request_queue_fifo_initialize(void)
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{
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// Allocate and Initialize the global deque
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runtime_global_deque = (struct deque_sandbox *)malloc(sizeof(struct deque_sandbox));
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assert(runtime_global_deque);
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// Note: Below is a Macro
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deque_init_sandbox(runtime_global_deque, RUNTIME_MAX_SANDBOX_REQUEST_COUNT);
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}
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static inline void
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sandbox_request_queue_ps_initialize(void)
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{
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// TODO
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}
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void
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sandbox_request_queue_initialize(void)
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{
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switch (sandbox_request_queue_policy) {
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case FIFO:
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return sandbox_request_queue_fifo_initialize();
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case PS:
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return sandbox_request_queue_ps_initialize();
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}
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}
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/**
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* Pushes a sandbox request to the global deque
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* @param sandbox_request
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**/
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static inline int
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sandbox_request_queue_fifo_add(sandbox_request_t *sandbox_request)
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{
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int return_code;
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// TODO: Running the runtime and listener cores on a single shared core is untested
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// We are unsure if the locking behavior is correct, so there may be deadlocks
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#if NCORES == 1
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pthread_mutex_lock(&runtime_global_deque_mutex);
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#endif
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return_code = deque_push_sandbox(runtime_global_deque, &sandbox_request);
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#if NCORES == 1
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pthread_mutex_unlock(&runtime_global_deque_mutex);
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#endif
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return return_code;
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}
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static inline int
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sandbox_request_queue_ps_add(sandbox_request_t *sandbox_request)
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{
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// TODO
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return 0;
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}
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/**
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* Pushes a sandbox request to the global deque
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* @param sandbox_request
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**/
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int
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sandbox_request_queue_add(sandbox_request_t *sandbox_request)
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{
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switch (sandbox_request_queue_policy) {
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case FIFO:
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return sandbox_request_queue_fifo_add(sandbox_request);
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case PS:
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return sandbox_request_queue_ps_add(sandbox_request);
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}
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}
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/**
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* Stealing from the dequeue is a lock-free, cross-core "pop", which removes the element from the end opposite to
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* "pop". Because the producer and consumer (the core stealine the sandbox request) modify different ends,
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* no locks are required, and coordination is achieved by instead retrying on inconsistent indices.
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*
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* Relevant Read: https://www.dre.vanderbilt.edu/~schmidt/PDF/work-stealing-dequeue.pdf
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*
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* TODO: Notice the mutex_lock for NCORES == 1 in both push/pop functions and steal calling 'pop' for NCORES == 1.
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* Ideally you don't call steal for same core consumption but I just made the steal API wrap that logic. Which is
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* perhaps not good. We might just add the #if in the scheduling code which should explicitly call "pop" for single core
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* and add an assert in "steal" function for NCORES == 1.
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*
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* @returns A Sandbox Request or NULL
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**/
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static inline sandbox_request_t *
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sandbox_request_queue_fifo_remove(void)
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{
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sandbox_request_t *sandbox_request = NULL;
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#if NCORES == 1
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pthread_mutex_lock(&runtime_global_deque_mutex);
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return_code = deque_pop_sandbox(runtime_global_deque, sandbox_request);
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pthread_mutex_unlock(&runtime_global_deque_mutex);
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#else
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int return_code = deque_steal_sandbox(runtime_global_deque, &sandbox_request);
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#endif
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if (return_code) sandbox_request = NULL;
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return sandbox_request;
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}
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static inline sandbox_request_t *
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sandbox_request_queue_ps_remove(void)
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{
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sandbox_request_t *sandbox_request = NULL;
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// TODO
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return sandbox_request;
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}
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sandbox_request_t *
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sandbox_request_queue_remove(void)
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{
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switch (sandbox_request_queue_policy) {
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case FIFO:
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return sandbox_request_queue_fifo_remove();
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case PS:
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return sandbox_request_queue_ps_remove();
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}
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}
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