Now one of the three eviction policies can be chosen as an argument. On
not specifying an argument, LRU is used by default.
Signed-off-by: Mahmoud Mandour <ma.mando...@gmail.com>
---
contrib/plugins/cache.c | 159 ++++++++++++++++++++++++++++++++++++----
1 file changed, 146 insertions(+), 13 deletions(-)
diff --git a/contrib/plugins/cache.c b/contrib/plugins/cache.c
index fa0bf1dd40..1e323494bf 100644
--- a/contrib/plugins/cache.c
+++ b/contrib/plugins/cache.c
@@ -18,6 +18,8 @@
QEMU_PLUGIN_EXPORT int qemu_plugin_version = QEMU_PLUGIN_VERSION;
+static bool fifo, lru, rnd;
+
static GRand *rng;
static GHashTable *dmiss_ht;
static GHashTable *imiss_ht;
@@ -55,6 +57,8 @@ struct CacheBlock {
struct CacheSet {
struct CacheBlock *blocks;
+ uint16_t *priorities;
+ GQueue *evict_queue;
};
struct Cache {
@@ -93,6 +97,84 @@ static inline uint64_t extract_set(struct Cache *cache,
uint64_t addr)
return (addr & cache->set_mask) >> (pow_of_two(cache->blksize));
}
+static void lru_priorities_init(struct Cache *cache)
+{
+ int i, j;
+
+ for (i = 0; i < cache->num_sets; i++) {
+ cache->sets[i].priorities = g_new(uint16_t, cache->assoc);
+ for (j = 0; j < cache->assoc; j++) {
+ cache->sets[i].priorities[j] = cache->assoc - j - 1;
+ }
+ }
+}
+
+static void lru_update_on_miss(struct Cache *cache,
+ int set_idx,
+ int blk_idx)
+{
+ int i;
+
+ for (i = 0; i < cache->assoc; i++) {
+ cache->sets[set_idx].priorities[i]++;
+ }
+
+ cache->sets[set_idx].priorities[blk_idx] = 0;
+}
+
+static void lru_update_on_hit(struct Cache *cache,
+ int set_idx,
+ int blk_idx)
+{
+ uint16_t blk_priority;
+ int i;
+
+ blk_priority = cache->sets[set_idx].priorities[blk_idx];
+ for (i = 0; i < cache->assoc; i++) {
+ if (cache->sets[set_idx].priorities[i] < blk_priority) {
+ cache->sets[set_idx].priorities[i]++;
+ }
+ }
+ cache->sets[set_idx].priorities[blk_idx] = 0;
+}
+
+static int lru_get_lru_block(struct Cache *cache, int set_idx)
+{
+ int i;
+
+ for (i = 0; i < cache->assoc; i++) {
+ if (cache->sets[set_idx].priorities[i] == cache->assoc - 1) {
+ return i;
+ }
+ }
+
+ g_assert_not_reached();
+}
+
+static void fifo_init(struct Cache *cache)
+{
+ int i;
+
+ for (i = 0; i < cache->num_sets; i++) {
+ cache->sets[i].evict_queue = g_queue_new();
+ }
+}
+
+static int fifo_get_first_in_block(struct Cache *cache, int set)
+{
+ GQueue *q = cache->sets[set].evict_queue;
+ return GPOINTER_TO_INT(g_queue_pop_tail(q));
+}
+
+static void fifo_update_on_miss(struct Cache *cache,
+ int set,
+ int blk_idx)
+{
+ GQueue *q = cache->sets[set].evict_queue;
+ g_queue_push_head(q, GINT_TO_POINTER(blk_idx));
+}
+
+
static struct Cache *cache_init(int blksize, int assoc, int cachesize)
{
struct Cache *cache;
@@ -113,6 +195,12 @@ static struct Cache *cache_init(int blksize, int assoc,
int cachesize)
cache->set_mask = ((cache->num_sets - 1) << (pow_of_two(cache->blksize)));
cache->tag_mask = ~(cache->set_mask | cache->blk_mask);
+ if (lru) {
+ lru_priorities_init(cache);
+ } else if (fifo) {
+ fifo_init(cache);
+ }
+
return cache;
}
@@ -131,12 +219,20 @@ static int get_invalid_block(struct Cache *cache,
uint64_t set)
return -1;
}
-static int get_replaced_block(struct Cache *cache)
+static int get_replaced_block(struct Cache *cache, int set)
{
- return g_rand_int_range(rng, 0, cache->assoc);
+ if (rnd) {
+ return g_rand_int_range(rng, 0, cache->assoc);
+ } else if (lru) {
+ return lru_get_lru_block(cache, set);
+ } else if (fifo) {
+ return fifo_get_first_in_block(cache, set);
+ }
+
+ g_assert_not_reached();
}
-static bool in_cache(struct Cache *cache, uint64_t addr)
+static int in_cache(struct Cache *cache, uint64_t addr)
{
int i;
uint64_t tag, set;
@@ -147,29 +243,39 @@ static bool in_cache(struct Cache *cache, uint64_t addr)
for (i = 0; i < cache->assoc; i++) {
if (cache->sets[set].blocks[i].tag == tag &&
cache->sets[set].blocks[i].valid) {
- return true;
+ return i;
}
}
- return false;
+ return -1;
}
static enum AccessResult access_cache(struct Cache *cache, uint64_t addr)
{
uint64_t tag, set;
- int replaced_blk;
-
- if (in_cache(cache, addr)) {
- return HIT;
- }
+ int hit_blk, replaced_blk;
tag = extract_tag(cache, addr);
set = extract_set(cache, addr);
+ hit_blk = in_cache(cache, addr);
+
+ if (hit_blk != -1) {
+ if (lru) {
+ lru_update_on_hit(cache, set, hit_blk);
+ }
+ return HIT;
+ }
replaced_blk = get_invalid_block(cache, set);
if (replaced_blk == -1) {
- replaced_blk = get_replaced_block(cache);
+ replaced_blk = get_replaced_block(cache, set);
+ }
+
+ if (lru) {
+ lru_update_on_miss(cache, set, replaced_blk);
+ } else if (fifo) {
+ fifo_update_on_miss(cache, set, replaced_blk);
}
cache->sets[set].blocks[replaced_blk].tag = tag;
@@ -307,6 +413,11 @@ static void free_cache(struct Cache *cache)
{
for (int i = 0; i < cache->num_sets; i++) {
g_free(cache->sets[i].blocks);
+ if (lru) {
+ g_free(cache->sets[i].priorities);
+ } else if (fifo) {
+ g_queue_free(cache->sets[i].evict_queue);
+ }
}
g_free(cache->sets);
@@ -403,8 +514,6 @@ int qemu_plugin_install(qemu_plugin_id_t id, const
qemu_info_t *info,
iblksize = 64;
icachesize = iblksize * iassoc * 32;
- rng = g_rand_new();
-
for (i = 0; i < argc; i++) {
char *opt = argv[i];
if (g_str_has_prefix(opt, "I=")) {
@@ -433,6 +542,22 @@ int qemu_plugin_install(qemu_plugin_id_t id, const
qemu_info_t *info,
if (!tracefile) {
fprintf(stderr, "could not open: %s for writing\n", file_name);
}
+ } else if (g_str_has_prefix(opt, "evict=")) {
+ if (lru || rnd || fifo) {
+ fprintf(stderr, "eviction policy specified more than once\n");
+ return -1;
+ }
+ gchar *policy = opt + 6;
+ if (g_strcmp0(policy, "rand") == 0) {
+ rnd = true;
+ } else if (g_strcmp0(policy, "lru") == 0) {
+ lru = true;
+ } else if (g_strcmp0(policy, "fifo") == 0) {
+ fifo = true;
+ } else {
+ fprintf(stderr, "invalid eviction policy: %s\n", opt);
+ return -1;
+ }
} else {
fprintf(stderr, "option parsing failed: %s\n", opt);
return -1;
@@ -449,6 +574,14 @@ int qemu_plugin_install(qemu_plugin_id_t id, const
qemu_info_t *info,
return -1;
}
+ if (!rnd && !lru && !fifo) {
+ lru = true;
+ }
+
+ if (rnd) {
+ rng = g_rand_new();
+ }
+
dcache = cache_init(dblksize, dassoc, dcachesize);
icache = cache_init(iblksize, iassoc, icachesize);
--
2.25.1
