--- /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>
+
+#include "common.h"
+#include "sc_annotation.h"
+
+#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)
+ {
+
+ }
+
+ bool equals(Value *other) {
+ if (!other)
+ return false;
+ return vX == other->vX && vY == other->vY && vZ == other->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);
+ }
+ for (int i = 0; i < CONCURRENCY_LEVEL; i++) {
+ segments[i] = new Segment;
+ }
+ }
+
+ 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) {
+ MODEL_ASSERT (key);
+ int hash = hashKey(key);
+
+ // 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
+ // This load action here makes it problematic for the SC analysis, what
+ // we need to do is as follows: if the get() method ever acquires the
+ // lock, we ignore this operation for the SC analysis, and otherwise we
+ // take it into consideration
+
+ SC_BEGIN();
+ Entry *firstPtr = first->load(acquire);
+ SC_END();
+
+ 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, this can be relaxed because the
+ // synchronization has been established by the load of head
+ e = e->next.load(relaxed);
+ }
+
+ // 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...
+
+ // Synchronized by locking, no need to be load acquire
+ Entry *newFirstPtr = first->load(relaxed);
+ if (e != NULL || firstPtr != newFirstPtr) {
+ e = newFirstPtr;
+ while (e != NULL) {
+ if (e->hash == hash && eq(key, e->key)) {
+ // Protected by lock, no need to be SC
+ res = e->value.load(relaxed);
+ seg->unlock(); // Critical region ends
+ 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 key or value
+ MODEL_ASSERT (key && value);
+
+ 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 *oldValue = 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 a relaxed (because locking synchronize
+ // with the previous put())?? no need to be acquire
+ oldValue = e->value.load(relaxed);
+ e->value.store(value, seq_cst);
+ seg->unlock(); // Don't forget to unlock before return
+ return oldValue;
+ }
+ // Synchronized by locking
+ e = e->next.load(relaxed);
+ }
+
+ // Add to front of list
+ Entry *newEntry = new Entry(hash, key, value, firstPtr);
+ // Publish the newEntry to others
+ first->store(newEntry, release);
+ seg->unlock(); // Critical region ends
+ return NULL;
+ }
+
+ Value* remove(Key *key, Value *value) {
+ MODEL_ASSERT (key);
+ 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 *oldValue = NULL;
+
+ // The written of the entry is synchronized by locking
+ Entry *firstPtr = first->load(relaxed);
+ e = firstPtr;
+
+ while (true) {
+ if (e != NULL) {
+ seg->unlock(); // Don't forget to unlock
+ return NULL;
+ }
+ if (e->hash == hash && eq(key, e->key))
+ break;
+ // Synchronized by locking
+ e = e->next.load(relaxed);
+ }
+
+ // FIXME: This could be a relaxed (because locking synchronize
+ // with the previous put())?? No need to be acquire
+ oldValue = e->value.load(relaxed);
+ // If the value parameter is NULL, we will remove the entry anyway
+ if (value != NULL && value->equals(oldValue)) {
+ seg->unlock();
+ return NULL;
+ }
+
+ // Force the get() to grab the lock and retry
+ e->value.store(NULL, relaxed);
+
+ // The strategy to remove the entry is to keep the entries after the
+ // removed one and copy the ones before it
+ Entry *head = e->next.load(relaxed);
+ Entry *p;
+ p = first->load(relaxed);
+ while (p != e) {
+ head = new Entry(p->hash, p->key, p->value.load(relaxed), head);
+ p = p->next.load(relaxed);
+ }
+
+ // Publish the new head to readers
+ first->store(head, release);
+ seg->unlock(); // Critical region ends
+ return oldValue;
+ }
+};
+
+#endif
projects / model-checker-benchmarks.git / blobdiff