--- /dev/null
+#ifndef _HASHMAP_H
+#define _HASHMAP_H
+
+#include <iostream>
+#include <atomic>
+#include "stdio.h"
+//#include <common.h>
+#ifdef STANDALONE
+#include <assert.h>
+#define MODEL_ASSERT assert
+#else
+#include <model-assert.h>
+#endif
+#include <stdlib.h>
+#include <mutex>
+
+#define relaxed memory_order_relaxed
+#define release memory_order_release
+#define acquire memory_order_acquire
+#define acq_rel memory_order_acq_rel
+#define seq_cst memory_order_seq_cst
+
+using namespace std;
+
+/**
+ For the sake of simplicity, we do not use template but some toy structs to
+ represent the Key and Value.
+*/
+struct Key {
+ // Probably represent the coordinate (x, y, z)
+ int x;
+ int y;
+ int z;
+
+ int hashCode() {
+ return x + 31 * y + 31 * 31 * z;
+ }
+
+ bool equals(Key *other) {
+ if (!other)
+ return false;
+ return x == other->x && y == other->y && z == other->z;
+ }
+
+ Key(int x, int y, int z) :
+ x(x),
+ y(y),
+ z(z)
+ {
+
+ }
+};
+
+struct Value {
+ // Probably represent the speed vector (vX, vY, vZ)
+ int vX;
+ int vY;
+ int vZ;
+
+ Value(int vX, int vY, int vZ) :
+ vX(vX),
+ vY(vY),
+ vZ(vZ)
+ {
+
+ }
+};
+
+class Entry {
+ public:
+ Key *key;
+ atomic<Value*> value;
+ int hash;
+ atomic<Entry*> next;
+
+ Entry(int h, Key *k, Value *v, Entry *n) {
+ this->hash = h;
+ this->key = k;
+ this->value.store(v, relaxed);
+ this->next.store(n, relaxed);
+ }
+};
+
+class Segment {
+ public:
+ int count;
+ mutex segMutex;
+
+ void lock() {
+ segMutex.lock();
+ }
+
+ void unlock() {
+ segMutex.unlock();
+ }
+
+ Segment() {
+ this->count = 0;
+ }
+};
+
+class HashMap {
+ public:
+ atomic<Entry*> *table;
+
+ int capacity;
+ int size;
+
+ static const int CONCURRENCY_LEVEL = 16;
+
+ static const int SEGMENT_MASK = CONCURRENCY_LEVEL - 1;
+
+ Segment segments[CONCURRENCY_LEVEL];
+
+ static const int DEFAULT_INITIAL_CAPACITY = 16;
+
+ // Not gonna consider resize now...
+
+ HashMap() {
+ this->size = 0;
+ this->capacity = DEFAULT_INITIAL_CAPACITY;
+ this->table = new atomic<Entry*>[capacity];
+ for (int i = 0; i < capacity; i++) {
+ atomic_init(&table[i], NULL);
+ }
+ }
+
+ int hashKey(Key *x) {
+ int h = x->hashCode();
+ // Use logical right shift
+ unsigned int tmp = (unsigned int) h;
+ return ((h << 7) - h + (tmp >> 9) + (tmp >> 17));
+ }
+
+ bool eq(Key *x, Key *y) {
+ return x == y || x->equals(y);
+ }
+
+ Value* get(Key *key) {
+ int hash = hashKey(key); // throws null pointer exception if key null
+
+ // Try first without locking...
+ atomic<Entry*> *tab = table;
+ int index = hash & (capacity - 1);
+ atomic<Entry*> *first = &tab[index];
+ Entry *e;
+ Value *res = NULL;
+
+ // Should be a load acquire
+ Entry *firstPtr = first->load(acquire);
+ e = firstPtr;
+ while (e != NULL) {
+ if (e->hash == hash && eq(key, e->key)) {
+ res = e->value.load(seq_cst);
+ if (res != NULL)
+ return res;
+ else
+ break;
+ // Loading the next entry
+ e = e->next.load(acquire);
+ }
+ }
+
+ // Recheck under synch if key apparently not there or interference
+ Segment seg = segments[hash & SEGMENT_MASK];
+ seg.lock(); // Critical region begins
+ // Not considering resize now, so ignore the reload of table...
+ atomic<Entry*> *newFirst = &tab[index];
+
+ // Synchronized by locking, no need to be load acquire
+ Entry *newFirstPtr = newFirst->load(relaxed);
+ if (e != NULL || firstPtr != newFirstPtr) {
+ e = newFirstPtr;
+ while (e != NULL) {
+ if (e->hash == hash && eq(key, e->key)) {
+ res = e->value.load(seq_cst);
+ return res;
+ }
+ // Synchronized by locking
+ e = e->next.load(relaxed);
+ }
+ }
+ seg.unlock(); // Critical region ends
+ return NULL;
+ }
+
+ Value* put(Key *key, Value *value) {
+ // Don't allow NULL value
+ //ASSERT (value != NULL);
+
+ int hash = hashKey(key);
+ Segment seg = segments[hash & SEGMENT_MASK];
+ atomic<Entry*> *tab;
+
+ seg.lock(); // Critical region begins
+ tab = table;
+ int index = hash & (capacity - 1);
+
+ atomic<Entry*> *first = &tab[index];
+ Entry *e;
+ Value *res = NULL;
+
+ // The written of the entry is synchronized by locking
+ Entry *firstPtr = first->load(relaxed);
+ e = firstPtr;
+ while (e != NULL) {
+ if (e->hash == hash && eq(key, e->key)) {
+ // FIXME: This could be an acquire??
+ res = e->value.load(acquire);
+ e->value.store(value, seq_cst);
+ seg.unlock(); // Don't forget to unlock before return
+ return res;
+ }
+ }
+
+ // Add to front of list
+ Entry *newEntry = new Entry(hash, key, value, firstPtr);
+ // Publish the newEntry to others
+ tab[index].store(newEntry, release);
+ seg.unlock(); // Critical region ends
+ return NULL;
+ }
+};
+
+#endif
--- /dev/null
+#include <iostream>
+#include <threads.h>
+#include "hashmap.h"
+
+HashMap *table;
+
+Key *k1, *k2;
+Value *r1, *r2, *r3, *r4, *v1, *v2;
+
+void printKey(Key *key) {
+ if (key)
+ printf("pos = (%d, %d, %d)\n", key->x, key->y, key->z);
+ else
+ printf("pos = NULL\n");
+}
+
+void printValue(Value *value) {
+ if (value)
+ printf("velocity = (%d, %d, %d)\n", value->vX, value->vY, value->vZ);
+ else
+ printf("velocity = NULL\n");
+}
+
+void threadA(void *arg) {
+ k1 = new Key(1, 1, 1);
+ k2 = new Key(3, 4, 5);
+ v1 = new Value(10, 10, 10);
+ r1 = table->put(k1, v1);
+ //printValue(r1);
+ r2 = table->get(k2);
+ printf("Thrd A:\n");
+ printValue(r2);
+}
+
+void threadB(void *arg) {
+ k1 = new Key(1, 1, 1);
+ k2 = new Key(3, 4, 5);
+ v2 = new Value(30, 40, 50);
+ r3 = table->put(k2, v2);
+ //printValue(r3);
+ r4 = table->get(k1);
+ printf("Thrd B:\n");
+ printValue(r4);
+}
+
+int user_main(int argc, char *argv[]) {
+ thrd_t t1, t2;
+ table = new HashMap;
+
+ thrd_create(&t1, threadA, NULL);
+ thrd_create(&t2, threadB, NULL);
+ thrd_join(t1);
+ thrd_join(t2);
+
+ return 0;
+}
+
+
projects / model-checker-benchmarks.git / commitdiff