#include <threads.h>
#include <stdlib.h>
-#include <stdatomic.h>
#include "librace.h"
#include "model-assert.h"
-
-typedef unsigned long long pointer;
-typedef atomic_ullong pointer_t;
-
-#define MAKE_POINTER(ptr, count) ((((pointer)count) << 32) | ptr)
-#define PTR_MASK 0xffffffffLL
-#define COUNT_MASK (0xffffffffLL << 32)
-
-static inline void set_count(pointer *p, unsigned int val) { *p = (*p & ~COUNT_MASK) | ((pointer)val << 32); }
-static inline void set_ptr(pointer *p, unsigned int val) { *p = (*p & ~PTR_MASK) | val; }
-static inline unsigned int get_count(pointer p) { return (p & COUNT_MASK) >> 32; }
-static inline unsigned int get_ptr(pointer p) { return p & PTR_MASK; }
-
-typedef struct node {
- unsigned int value;
- pointer_t next;
-} node_t;
-
-typedef struct {
- pointer_t head;
- pointer_t tail;
- node_t nodes[MAX_NODES + 1];
-} queue_t;
-
-void init_queue(queue_t *q, int num_threads);
-
-#include <list>
-using namespace std;
-/**
- @Begin
- @Global_define:
- @DeclareStruct:
- typedef struct tag_elem {
- Tag id;
- unsigned int data;
- } tag_elem_t;
-
- @DeclareVar:
- list<tag_elem_t> __queue;
- Tag tag;
- @InitVar:
- __queue = list<tag_elem_t>();
- tag = 1; // Beginning of available id
- @Happens_before:
- # Only check the happens-before relationship according to the id of the
- # commit_point_set. For commit_point_set that has same ID, A -> B means
- # B happens after the previous A.
- Enqueue -> Dequeue
- @End
-*/
-
-
-int get_thread_num();
-
+#include "my_queue.h"
#define relaxed memory_order_relaxed
#define release memory_order_release
#define acquire memory_order_acquire
#define MAX_FREELIST 4 /* Each thread can own up to MAX_FREELIST free nodes */
-#define INITIAL_FREE 2 /* Each thread starts with INITIAL_FREE free nodes */
+#define INITIAL_FREE 3 /* Each thread starts with INITIAL_FREE free nodes */
#define POISON_IDX 0x666
int i;
int t = get_thread_num();
for (i = 0; i < MAX_FREELIST; i++) {
- unsigned int node = load_32(&free_lists[t][i]);
+ //unsigned int node = load_32(&free_lists[t][i]);
+ unsigned int node = free_lists[t][i];
if (node) {
- store_32(&free_lists[t][i], 0);
+ //store_32(&free_lists[t][i], 0);
+ free_lists[t][i] = 0;
return node;
}
}
/* free_list is empty? */
- MODEL_ASSERT(0);
+ //MODEL_ASSERT(0);
return 0;
}
int t = get_thread_num();
/* Don't reclaim NULL node */
- MODEL_ASSERT(node);
+ //MODEL_ASSERT(node);
for (i = 0; i < MAX_FREELIST; i++) {
/* Should never race with our own thread here */
- unsigned int idx = load_32(&free_lists[t][i]);
+ //unsigned int idx = load_32(&free_lists[t][i]);
+ unsigned int idx = free_lists[t][i];
/* Found empty spot in free list */
if (idx == 0) {
store_32(&free_lists[t][i], node);
+ //free_lists[t][i] = node;
return;
}
}
/* free list is full? */
- MODEL_ASSERT(0);
+ //MODEL_ASSERT(0);
}
void init_queue(queue_t *q, int num_threads)
{
- /**
- @Begin
- @Entry_point
- @End
- */
-
int i, j;
+ for (i = 0; i < MAX_NODES; i++) {
+ atomic_init(&q->nodes[i].next, MAKE_POINTER(POISON_IDX, 0));
+ }
/* Initialize each thread's free list with INITIAL_FREE pointers */
/* The actual nodes are initialized with poison indexes */
- free_lists = (unsigned int**) malloc(num_threads * sizeof(*free_lists));
+ free_lists = malloc(num_threads * sizeof(*free_lists));
for (i = 0; i < num_threads; i++) {
for (j = 0; j < INITIAL_FREE; j++) {
free_lists[i][j] = 2 + i * MAX_FREELIST + j;
/**
@Begin
- @Interface: Enqueue
- @Commit_point_set: Enqueue_Success_Point
- @ID: tag++
- @Action:
- # __ID__ is an internal macro that refers to the id of the current
- # interface call
- tag_elem_t elem;
- elem.id = __ID__;
- elem.data = val;
- __queue.push_back(elem);
+ @Interface_define: Enqueue
@End
*/
void enqueue(queue_t *q, unsigned int val)
pointer tmp;
node = new_node();
- store_32(&q->nodes[node].value, val);
+ //store_32(&q->nodes[node].value, val);
+ q->nodes[node].value = val;
tmp = atomic_load_explicit(&q->nodes[node].next, relaxed);
set_ptr(&tmp, 0); // NULL
atomic_store_explicit(&q->nodes[node].next, tmp, relaxed);
while (!success) {
+
+ /**
+ @Begin
+ @Commit_point_clear: true
+ @Label: Enqueue_Clear
+ @End
+ */
+ /**** UL & inadmissible ****/
tail = atomic_load_explicit(&q->tail, acquire);
+ /****FIXME: miss ****/
next = atomic_load_explicit(&q->nodes[get_ptr(tail)].next, acquire);
+ //printf("miss1_enqueue\n");
if (tail == atomic_load_explicit(&q->tail, relaxed)) {
/* Check for uninitialized 'next' */
- MODEL_ASSERT(get_ptr(next) != POISON_IDX);
+ //MODEL_ASSERT(get_ptr(next) != POISON_IDX);
if (get_ptr(next) == 0) { // == NULL
pointer value = MAKE_POINTER(node, get_count(next) + 1);
+ /**** SPEC Error (testcase1.c) ****/
+ // Second release can be just relaxed
success = atomic_compare_exchange_strong_explicit(&q->nodes[get_ptr(tail)].next,
- &next, value, release, release);
+ &next, value, release, relaxed);
+ /**
+ @Begin
+ @Commit_point_define_check: success
+ @Label: EnqueueUpdateNext
+ @End
+ */
}
if (!success) {
+ // This routine helps the other enqueue to update the tail
+ /**** UL & Inadmissible ****/
unsigned int ptr = get_ptr(atomic_load_explicit(&q->nodes[get_ptr(tail)].next, acquire));
pointer value = MAKE_POINTER(ptr,
get_count(tail) + 1);
- int commit_success = 0;
- commit_success = atomic_compare_exchange_strong_explicit(&q->tail,
- &tail, value, release, release);
- /**
- @Begin
- @Commit_point_define_check: commit_success == true
- @Label: Enqueue_Success_Point
- @End
- */
+ /****FIXME: miss ****/
+ // Second release can be just relaxed
+ bool succ = false;
+ succ = atomic_compare_exchange_strong_explicit(&q->tail,
+ &tail, value, release, relaxed);
+ if (succ) {
+ //printf("miss2_enqueue CAS succ\n");
+ }
+ //printf("miss2_enqueue\n");
thrd_yield();
}
}
}
- atomic_compare_exchange_strong_explicit(&q->tail,
+ /**** UL & Inadmissible ****/
+ // Second release can be just relaxed
+ bool succ = atomic_compare_exchange_strong_explicit(&q->tail,
&tail,
MAKE_POINTER(node, get_count(tail) + 1),
- release, release);
+ release, relaxed);
}
/**
@Begin
- @Interface: Dequeue
- @Commit_point_set: Dequeue_Success_Point
- @ID: __queue.back().id
- @Action:
- unsigned int _Old_Val = __queue.front().data;
- __queue.pop_front();
- @Post_check:
- _Old_Val == __RET__
+ @Interface_define: Dequeue
@End
*/
-unsigned int dequeue(queue_t *q)
+bool dequeue(queue_t *q, int *retVal)
{
- unsigned int value;
+ unsigned int value = 0;
int success = 0;
pointer head;
pointer tail;
pointer next;
while (!success) {
+ /**
+ @Begin
+ @Commit_point_clear: true
+ @Label: Dequeue_Clear
+ @End
+ */
+ /**** Inadmissible ****/
head = atomic_load_explicit(&q->head, acquire);
- tail = atomic_load_explicit(&q->tail, relaxed);
- next = atomic_load_explicit(&q->nodes[get_ptr(head)].next, acquire);
+ /**
+ @Begin
+ @Commit_point_define_check: true
+ @Label: DequeueReadHead
+ @End
+ */
+
+ /** A new bug has been found here!!! It should be acquire instead of
+ * relaxed (it introduces a bug when there's two dequeuers and one
+ * enqueuer) correctness bug!!
+ */
+ /**** New bug ****/
+ tail = atomic_load_explicit(&q->tail, acquire);
+
+ /**** SPEC Error (testcase1.c) ****/
+ next = atomic_load_explicit(&q->nodes[get_ptr(head)].next, relaxed);
+ /**
+ @Begin
+ @Potential_commit_point_define: true
+ @Label: DequeueReadNext
+ @End
+ */
if (atomic_load_explicit(&q->head, relaxed) == head) {
if (get_ptr(head) == get_ptr(tail)) {
/* Check for uninitialized 'next' */
- MODEL_ASSERT(get_ptr(next) != POISON_IDX);
+ //MODEL_ASSERT(get_ptr(next) != POISON_IDX);
- if (get_ptr(next) == 0) { // NULL
- return 0; // NULL
+ if (get_ptr(next) == 0) { // NULL
+ return false; // NULL
}
- atomic_compare_exchange_strong_explicit(&q->tail,
+ /**** FIXME: miss ****/
+ // Second release can be just relaxed
+ bool succ = false;
+ succ = atomic_compare_exchange_strong_explicit(&q->tail,
&tail,
MAKE_POINTER(get_ptr(next), get_count(tail) + 1),
- release, release);
+ release, relaxed);
+ if (succ) {
+ //printf("miss4_dequeue CAS succ\n");
+ }
+ //printf("miss4_dequeue\n");
thrd_yield();
} else {
- value = load_32(&q->nodes[get_ptr(next)].value);
+ //value = load_32(&q->nodes[get_ptr(next)].value);
+ value = q->nodes[get_ptr(next)].value;
+ /**** inadmissibility ****/
success = atomic_compare_exchange_strong_explicit(&q->head,
&head,
MAKE_POINTER(get_ptr(next), get_count(head) + 1),
- release, release);
+ release, relaxed);
/**
@Begin
- @Commit_point_define_check: success == true
- @Label: Dequeue_Success_Point
+ @Commit_point_define_check: success
+ @Label: DequeueUpdateHead
+ @End
+ */
+
+ /**
+ @Begin
+ @Commit_point_define: success
+ @Potential_commit_point_label: DequeueReadNext
+ @Label: DequeueReadNextVerify
@End
*/
if (!success)
}
}
reclaim(get_ptr(head));
- return value;
-}
-
-
-
-#include <stdlib.h>
-#include <stdio.h>
-#include <threads.h>
-
-#include "my_queue.h"
-#include "model-assert.h"
-
-static int procs = 2;
-static queue_t *queue;
-static thrd_t *threads;
-static unsigned int *input;
-static unsigned int *output;
-static int num_threads;
-
-int get_thread_num()
-{
- thrd_t curr = thrd_current();
- int i;
- for (i = 0; i < num_threads; i++)
- if (curr.priv == threads[i].priv)
- return i;
- MODEL_ASSERT(0);
- return -1;
-}
-
-static void main_task(void *param)
-{
- unsigned int val;
- int pid = *((int *)param);
-
- if (!pid) {
- input[0] = 17;
- enqueue(queue, input[0]);
- output[0] = dequeue(queue);
- } else {
- input[1] = 37;
- enqueue(queue, input[1]);
- output[1] = dequeue(queue);
- }
-}
-
-int user_main(int argc, char **argv)
-{
- int i;
- int *param;
- unsigned int in_sum = 0, out_sum = 0;
-
- queue = (queue_t*) calloc(1, sizeof(*queue));
- MODEL_ASSERT(queue);
-
- num_threads = procs;
- threads = (thrd_t*) malloc(num_threads * sizeof(thrd_t));
- param = (int*) malloc(num_threads * sizeof(*param));
- input = (unsigned int*) calloc(num_threads, sizeof(*input));
- output = (unsigned int*) calloc(num_threads, sizeof(*output));
-
- init_queue(queue, num_threads);
- for (i = 0; i < num_threads; i++) {
- param[i] = i;
- thrd_create(&threads[i], main_task, ¶m[i]);
- }
- for (i = 0; i < num_threads; i++)
- thrd_join(threads[i]);
-
- for (i = 0; i < num_threads; i++) {
- in_sum += input[i];
- out_sum += output[i];
- }
- for (i = 0; i < num_threads; i++)
- printf("input[%d] = %u\n", i, input[i]);
- for (i = 0; i < num_threads; i++)
- printf("output[%d] = %u\n", i, output[i]);
- MODEL_ASSERT(in_sum == out_sum);
-
- free(param);
- free(threads);
- free(queue);
-
- return 0;
+ *retVal = value;
+ return true;
}
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