X-Git-Url: http://review.tizen.org/git/?a=blobdiff_plain;f=name-hash.c;h=5d3c7b12c1805cad19e8cef165e79e232d0f4de4;hb=a78305ffbca58e49a7cdad901df0ae779bbed8fb;hp=6d9f23e932559c58c9ebf4679a6035889f726ed2;hpb=d834fa901eea94428ea656a6127f303bc95fb73f;p=platform%2Fupstream%2Fgit.git

diff --git a/name-hash.c b/name-hash.c
index 6d9f23e..5d3c7b1 100644
--- a/name-hash.c
+++ b/name-hash.c
@@ -5,8 +5,8 @@
  *
  * Copyright (C) 2008 Linus Torvalds
  */
-#define NO_THE_INDEX_COMPATIBILITY_MACROS
 #include "cache.h"
+#include "thread-utils.h"
 
 struct dir_entry {
 	struct hashmap_entry ent;
@@ -16,20 +16,34 @@ struct dir_entry {
 	char name[FLEX_ARRAY];
 };
 
-static int dir_entry_cmp(const struct dir_entry *e1,
-		const struct dir_entry *e2, const char *name)
+static int dir_entry_cmp(const void *unused_cmp_data,
+			 const struct hashmap_entry *eptr,
+			 const struct hashmap_entry *entry_or_key,
+			 const void *keydata)
 {
+	const struct dir_entry *e1, *e2;
+	const char *name = keydata;
+
+	e1 = container_of(eptr, const struct dir_entry, ent);
+	e2 = container_of(entry_or_key, const struct dir_entry, ent);
+
 	return e1->namelen != e2->namelen || strncasecmp(e1->name,
 			name ? name : e2->name, e1->namelen);
 }
 
-static struct dir_entry *find_dir_entry(struct index_state *istate,
-		const char *name, unsigned int namelen)
+static struct dir_entry *find_dir_entry__hash(struct index_state *istate,
+		const char *name, unsigned int namelen, unsigned int hash)
 {
 	struct dir_entry key;
-	hashmap_entry_init(&key, memihash(name, namelen));
+	hashmap_entry_init(&key.ent, hash);
 	key.namelen = namelen;
-	return hashmap_get(&istate->dir_hash, &key, name);
+	return hashmap_get_entry(&istate->dir_hash, &key, ent, name);
+}
+
+static struct dir_entry *find_dir_entry(struct index_state *istate,
+		const char *name, unsigned int namelen)
+{
+	return find_dir_entry__hash(istate, name, namelen, memihash(name, namelen));
 }
 
 static struct dir_entry *hash_dir_entry(struct index_state *istate,
@@ -56,9 +70,9 @@ static struct dir_entry *hash_dir_entry(struct index_state *istate,
 	if (!dir) {
 		/* not found, create it and add to hash table */
 		FLEX_ALLOC_MEM(dir, name, ce->name, namelen);
-		hashmap_entry_init(dir, memihash(ce->name, namelen));
+		hashmap_entry_init(&dir->ent, memihash(ce->name, namelen));
 		dir->namelen = namelen;
-		hashmap_add(&istate->dir_hash, dir);
+		hashmap_add(&istate->dir_hash, &dir->ent);
 
 		/* recursively add missing parent directories */
 		dir->parent = hash_dir_entry(istate, ce, namelen);
@@ -83,7 +97,7 @@ static void remove_dir_entry(struct index_state *istate, struct cache_entry *ce)
 	struct dir_entry *dir = hash_dir_entry(istate, ce, ce_namelen(ce));
 	while (dir && !(--dir->nr)) {
 		struct dir_entry *parent = dir->parent;
-		hashmap_remove(&istate->dir_hash, dir, NULL);
+		hashmap_remove(&istate->dir_hash, &dir->ent, NULL);
 		free(dir);
 		dir = parent;
 	}
@@ -94,16 +108,23 @@ static void hash_index_entry(struct index_state *istate, struct cache_entry *ce)
 	if (ce->ce_flags & CE_HASHED)
 		return;
 	ce->ce_flags |= CE_HASHED;
-	hashmap_entry_init(ce, memihash(ce->name, ce_namelen(ce)));
-	hashmap_add(&istate->name_hash, ce);
+	hashmap_entry_init(&ce->ent, memihash(ce->name, ce_namelen(ce)));
+	hashmap_add(&istate->name_hash, &ce->ent);
 
 	if (ignore_case)
 		add_dir_entry(istate, ce);
 }
 
-static int cache_entry_cmp(const struct cache_entry *ce1,
-		const struct cache_entry *ce2, const void *remove)
+static int cache_entry_cmp(const void *unused_cmp_data,
+			   const struct hashmap_entry *eptr,
+			   const struct hashmap_entry *entry_or_key,
+			   const void *remove)
 {
+	const struct cache_entry *ce1, *ce2;
+
+	ce1 = container_of(eptr, const struct cache_entry, ent);
+	ce2 = container_of(entry_or_key, const struct cache_entry, ent);
+
 	/*
 	 * For remove_name_hash, find the exact entry (pointer equality); for
 	 * index_file_exists, find all entries with matching hash code and
@@ -112,18 +133,490 @@ static int cache_entry_cmp(const struct cache_entry *ce1,
 	return remove ? !(ce1 == ce2) : 0;
 }
 
+static int lazy_try_threaded = 1;
+static int lazy_nr_dir_threads;
+
+/*
+ * Set a minimum number of cache_entries that we will handle per
+ * thread and use that to decide how many threads to run (up to
+ * the number on the system).
+ *
+ * For guidance setting the lower per-thread bound, see:
+ *     t/helper/test-lazy-init-name-hash --analyze
+ */
+#define LAZY_THREAD_COST (2000)
+
+/*
+ * We use n mutexes to guard n partitions of the "istate->dir_hash"
+ * hashtable.  Since "find" and "insert" operations will hash to a
+ * particular bucket and modify/search a single chain, we can say
+ * that "all chains mod n" are guarded by the same mutex -- rather
+ * than having a single mutex to guard the entire table.  (This does
+ * require that we disable "rehashing" on the hashtable.)
+ *
+ * So, a larger value here decreases the probability of a collision
+ * and the time that each thread must wait for the mutex.
+ */
+#define LAZY_MAX_MUTEX   (32)
+
+static pthread_mutex_t *lazy_dir_mutex_array;
+
+/*
+ * An array of lazy_entry items is used by the n threads in
+ * the directory parse (first) phase to (lock-free) store the
+ * intermediate results.  These values are then referenced by
+ * the 2 threads in the second phase.
+ */
+struct lazy_entry {
+	struct dir_entry *dir;
+	unsigned int hash_dir;
+	unsigned int hash_name;
+};
+
+/*
+ * Decide if we want to use threads (if available) to load
+ * the hash tables.  We set "lazy_nr_dir_threads" to zero when
+ * it is not worth it.
+ */
+static int lookup_lazy_params(struct index_state *istate)
+{
+	int nr_cpus;
+
+	lazy_nr_dir_threads = 0;
+
+	if (!lazy_try_threaded)
+		return 0;
+
+	/*
+	 * If we are respecting case, just use the original
+	 * code to build the "istate->name_hash".  We don't
+	 * need the complexity here.
+	 */
+	if (!ignore_case)
+		return 0;
+
+	nr_cpus = online_cpus();
+	if (nr_cpus < 2)
+		return 0;
+
+	if (istate->cache_nr < 2 * LAZY_THREAD_COST)
+		return 0;
+
+	if (istate->cache_nr < nr_cpus * LAZY_THREAD_COST)
+		nr_cpus = istate->cache_nr / LAZY_THREAD_COST;
+	lazy_nr_dir_threads = nr_cpus;
+	return lazy_nr_dir_threads;
+}
+
+/*
+ * Initialize n mutexes for use when searching and inserting
+ * into "istate->dir_hash".  All "dir" threads are trying
+ * to insert partial pathnames into the hash as they iterate
+ * over their portions of the index, so lock contention is
+ * high.
+ *
+ * However, the hashmap is going to put items into bucket
+ * chains based on their hash values.  Use that to create n
+ * mutexes and lock on mutex[bucket(hash) % n].  This will
+ * decrease the collision rate by (hopefully) a factor of n.
+ */
+static void init_dir_mutex(void)
+{
+	int j;
+
+	lazy_dir_mutex_array = xcalloc(LAZY_MAX_MUTEX, sizeof(pthread_mutex_t));
+
+	for (j = 0; j < LAZY_MAX_MUTEX; j++)
+		init_recursive_mutex(&lazy_dir_mutex_array[j]);
+}
+
+static void cleanup_dir_mutex(void)
+{
+	int j;
+
+	for (j = 0; j < LAZY_MAX_MUTEX; j++)
+		pthread_mutex_destroy(&lazy_dir_mutex_array[j]);
+
+	free(lazy_dir_mutex_array);
+}
+
+static void lock_dir_mutex(int j)
+{
+	pthread_mutex_lock(&lazy_dir_mutex_array[j]);
+}
+
+static void unlock_dir_mutex(int j)
+{
+	pthread_mutex_unlock(&lazy_dir_mutex_array[j]);
+}
+
+static inline int compute_dir_lock_nr(
+	const struct hashmap *map,
+	unsigned int hash)
+{
+	return hashmap_bucket(map, hash) % LAZY_MAX_MUTEX;
+}
+
+static struct dir_entry *hash_dir_entry_with_parent_and_prefix(
+	struct index_state *istate,
+	struct dir_entry *parent,
+	struct strbuf *prefix)
+{
+	struct dir_entry *dir;
+	unsigned int hash;
+	int lock_nr;
+
+	/*
+	 * Either we have a parent directory and path with slash(es)
+	 * or the directory is an immediate child of the root directory.
+	 */
+	assert((parent != NULL) ^ (strchr(prefix->buf, '/') == NULL));
+
+	if (parent)
+		hash = memihash_cont(parent->ent.hash,
+			prefix->buf + parent->namelen,
+			prefix->len - parent->namelen);
+	else
+		hash = memihash(prefix->buf, prefix->len);
+
+	lock_nr = compute_dir_lock_nr(&istate->dir_hash, hash);
+	lock_dir_mutex(lock_nr);
+
+	dir = find_dir_entry__hash(istate, prefix->buf, prefix->len, hash);
+	if (!dir) {
+		FLEX_ALLOC_MEM(dir, name, prefix->buf, prefix->len);
+		hashmap_entry_init(&dir->ent, hash);
+		dir->namelen = prefix->len;
+		dir->parent = parent;
+		hashmap_add(&istate->dir_hash, &dir->ent);
+
+		if (parent) {
+			unlock_dir_mutex(lock_nr);
+
+			/* All I really need here is an InterlockedIncrement(&(parent->nr)) */
+			lock_nr = compute_dir_lock_nr(&istate->dir_hash, parent->ent.hash);
+			lock_dir_mutex(lock_nr);
+			parent->nr++;
+		}
+	}
+
+	unlock_dir_mutex(lock_nr);
+
+	return dir;
+}
+
+/*
+ * handle_range_1() and handle_range_dir() are derived from
+ * clear_ce_flags_1() and clear_ce_flags_dir() in unpack-trees.c
+ * and handle the iteration over the entire array of index entries.
+ * They use recursion for adjacent entries in the same parent
+ * directory.
+ */
+static int handle_range_1(
+	struct index_state *istate,
+	int k_start,
+	int k_end,
+	struct dir_entry *parent,
+	struct strbuf *prefix,
+	struct lazy_entry *lazy_entries);
+
+static int handle_range_dir(
+	struct index_state *istate,
+	int k_start,
+	int k_end,
+	struct dir_entry *parent,
+	struct strbuf *prefix,
+	struct lazy_entry *lazy_entries,
+	struct dir_entry **dir_new_out)
+{
+	int rc, k;
+	int input_prefix_len = prefix->len;
+	struct dir_entry *dir_new;
+
+	dir_new = hash_dir_entry_with_parent_and_prefix(istate, parent, prefix);
+
+	strbuf_addch(prefix, '/');
+
+	/*
+	 * Scan forward in the index array for index entries having the same
+	 * path prefix (that are also in this directory).
+	 */
+	if (k_start + 1 >= k_end)
+		k = k_end;
+	else if (strncmp(istate->cache[k_start + 1]->name, prefix->buf, prefix->len) > 0)
+		k = k_start + 1;
+	else if (strncmp(istate->cache[k_end - 1]->name, prefix->buf, prefix->len) == 0)
+		k = k_end;
+	else {
+		int begin = k_start;
+		int end = k_end;
+		assert(begin >= 0);
+		while (begin < end) {
+			int mid = begin + ((end - begin) >> 1);
+			int cmp = strncmp(istate->cache[mid]->name, prefix->buf, prefix->len);
+			if (cmp == 0) /* mid has same prefix; look in second part */
+				begin = mid + 1;
+			else if (cmp > 0) /* mid is past group; look in first part */
+				end = mid;
+			else
+				die("cache entry out of order");
+		}
+		k = begin;
+	}
+
+	/*
+	 * Recurse and process what we can of this subset [k_start, k).
+	 */
+	rc = handle_range_1(istate, k_start, k, dir_new, prefix, lazy_entries);
+
+	strbuf_setlen(prefix, input_prefix_len);
+
+	*dir_new_out = dir_new;
+	return rc;
+}
+
+static int handle_range_1(
+	struct index_state *istate,
+	int k_start,
+	int k_end,
+	struct dir_entry *parent,
+	struct strbuf *prefix,
+	struct lazy_entry *lazy_entries)
+{
+	int input_prefix_len = prefix->len;
+	int k = k_start;
+
+	while (k < k_end) {
+		struct cache_entry *ce_k = istate->cache[k];
+		const char *name, *slash;
+
+		if (prefix->len && strncmp(ce_k->name, prefix->buf, prefix->len))
+			break;
+
+		name = ce_k->name + prefix->len;
+		slash = strchr(name, '/');
+
+		if (slash) {
+			int len = slash - name;
+			int processed;
+			struct dir_entry *dir_new;
+
+			strbuf_add(prefix, name, len);
+			processed = handle_range_dir(istate, k, k_end, parent, prefix, lazy_entries, &dir_new);
+			if (processed) {
+				k += processed;
+				strbuf_setlen(prefix, input_prefix_len);
+				continue;
+			}
+
+			strbuf_addch(prefix, '/');
+			processed = handle_range_1(istate, k, k_end, dir_new, prefix, lazy_entries);
+			k += processed;
+			strbuf_setlen(prefix, input_prefix_len);
+			continue;
+		}
+
+		/*
+		 * It is too expensive to take a lock to insert "ce_k"
+		 * into "istate->name_hash" and increment the ref-count
+		 * on the "parent" dir.  So we defer actually updating
+		 * permanent data structures until phase 2 (where we
+		 * can change the locking requirements) and simply
+		 * accumulate our current results into the lazy_entries
+		 * data array).
+		 *
+		 * We do not need to lock the lazy_entries array because
+		 * we have exclusive access to the cells in the range
+		 * [k_start,k_end) that this thread was given.
+		 */
+		lazy_entries[k].dir = parent;
+		if (parent) {
+			lazy_entries[k].hash_name = memihash_cont(
+				parent->ent.hash,
+				ce_k->name + parent->namelen,
+				ce_namelen(ce_k) - parent->namelen);
+			lazy_entries[k].hash_dir = parent->ent.hash;
+		} else {
+			lazy_entries[k].hash_name = memihash(ce_k->name, ce_namelen(ce_k));
+		}
+
+		k++;
+	}
+
+	return k - k_start;
+}
+
+struct lazy_dir_thread_data {
+	pthread_t pthread;
+	struct index_state *istate;
+	struct lazy_entry *lazy_entries;
+	int k_start;
+	int k_end;
+};
+
+static void *lazy_dir_thread_proc(void *_data)
+{
+	struct lazy_dir_thread_data *d = _data;
+	struct strbuf prefix = STRBUF_INIT;
+	handle_range_1(d->istate, d->k_start, d->k_end, NULL, &prefix, d->lazy_entries);
+	strbuf_release(&prefix);
+	return NULL;
+}
+
+struct lazy_name_thread_data {
+	pthread_t pthread;
+	struct index_state *istate;
+	struct lazy_entry *lazy_entries;
+};
+
+static void *lazy_name_thread_proc(void *_data)
+{
+	struct lazy_name_thread_data *d = _data;
+	int k;
+
+	for (k = 0; k < d->istate->cache_nr; k++) {
+		struct cache_entry *ce_k = d->istate->cache[k];
+		ce_k->ce_flags |= CE_HASHED;
+		hashmap_entry_init(&ce_k->ent, d->lazy_entries[k].hash_name);
+		hashmap_add(&d->istate->name_hash, &ce_k->ent);
+	}
+
+	return NULL;
+}
+
+static inline void lazy_update_dir_ref_counts(
+	struct index_state *istate,
+	struct lazy_entry *lazy_entries)
+{
+	int k;
+
+	for (k = 0; k < istate->cache_nr; k++) {
+		if (lazy_entries[k].dir)
+			lazy_entries[k].dir->nr++;
+	}
+}
+
+static void threaded_lazy_init_name_hash(
+	struct index_state *istate)
+{
+	int err;
+	int nr_each;
+	int k_start;
+	int t;
+	struct lazy_entry *lazy_entries;
+	struct lazy_dir_thread_data *td_dir;
+	struct lazy_name_thread_data *td_name;
+
+	if (!HAVE_THREADS)
+		return;
+
+	k_start = 0;
+	nr_each = DIV_ROUND_UP(istate->cache_nr, lazy_nr_dir_threads);
+
+	lazy_entries = xcalloc(istate->cache_nr, sizeof(struct lazy_entry));
+	td_dir = xcalloc(lazy_nr_dir_threads, sizeof(struct lazy_dir_thread_data));
+	td_name = xcalloc(1, sizeof(struct lazy_name_thread_data));
+
+	init_dir_mutex();
+
+	/*
+	 * Phase 1:
+	 * Build "istate->dir_hash" using n "dir" threads (and a read-only index).
+	 */
+	for (t = 0; t < lazy_nr_dir_threads; t++) {
+		struct lazy_dir_thread_data *td_dir_t = td_dir + t;
+		td_dir_t->istate = istate;
+		td_dir_t->lazy_entries = lazy_entries;
+		td_dir_t->k_start = k_start;
+		k_start += nr_each;
+		if (k_start > istate->cache_nr)
+			k_start = istate->cache_nr;
+		td_dir_t->k_end = k_start;
+		err = pthread_create(&td_dir_t->pthread, NULL, lazy_dir_thread_proc, td_dir_t);
+		if (err)
+			die(_("unable to create lazy_dir thread: %s"), strerror(err));
+	}
+	for (t = 0; t < lazy_nr_dir_threads; t++) {
+		struct lazy_dir_thread_data *td_dir_t = td_dir + t;
+		if (pthread_join(td_dir_t->pthread, NULL))
+			die("unable to join lazy_dir_thread");
+	}
+
+	/*
+	 * Phase 2:
+	 * Iterate over all index entries and add them to the "istate->name_hash"
+	 * using a single "name" background thread.
+	 * (Testing showed it wasn't worth running more than 1 thread for this.)
+	 *
+	 * Meanwhile, finish updating the parent directory ref-counts for each
+	 * index entry using the current thread.  (This step is very fast and
+	 * doesn't need threading.)
+	 */
+	td_name->istate = istate;
+	td_name->lazy_entries = lazy_entries;
+	err = pthread_create(&td_name->pthread, NULL, lazy_name_thread_proc, td_name);
+	if (err)
+		die(_("unable to create lazy_name thread: %s"), strerror(err));
+
+	lazy_update_dir_ref_counts(istate, lazy_entries);
+
+	err = pthread_join(td_name->pthread, NULL);
+	if (err)
+		die(_("unable to join lazy_name thread: %s"), strerror(err));
+
+	cleanup_dir_mutex();
+
+	free(td_name);
+	free(td_dir);
+	free(lazy_entries);
+}
+
 static void lazy_init_name_hash(struct index_state *istate)
 {
-	int nr;
 
 	if (istate->name_hash_initialized)
 		return;
-	hashmap_init(&istate->name_hash, (hashmap_cmp_fn) cache_entry_cmp,
-			istate->cache_nr);
-	hashmap_init(&istate->dir_hash, (hashmap_cmp_fn) dir_entry_cmp, 0);
-	for (nr = 0; nr < istate->cache_nr; nr++)
-		hash_index_entry(istate, istate->cache[nr]);
+	trace_performance_enter();
+	hashmap_init(&istate->name_hash, cache_entry_cmp, NULL, istate->cache_nr);
+	hashmap_init(&istate->dir_hash, dir_entry_cmp, NULL, istate->cache_nr);
+
+	if (lookup_lazy_params(istate)) {
+		/*
+		 * Disable item counting and automatic rehashing because
+		 * we do per-chain (mod n) locking rather than whole hashmap
+		 * locking and we need to prevent the table-size from changing
+		 * and bucket items from being redistributed.
+		 */
+		hashmap_disable_item_counting(&istate->dir_hash);
+		threaded_lazy_init_name_hash(istate);
+		hashmap_enable_item_counting(&istate->dir_hash);
+	} else {
+		int nr;
+		for (nr = 0; nr < istate->cache_nr; nr++)
+			hash_index_entry(istate, istate->cache[nr]);
+	}
+
 	istate->name_hash_initialized = 1;
+	trace_performance_leave("initialize name hash");
+}
+
+/*
+ * A test routine for t/helper/ sources.
+ *
+ * Returns the number of threads used or 0 when
+ * the non-threaded code path was used.
+ *
+ * Requesting threading WILL NOT override guards
+ * in lookup_lazy_params().
+ */
+int test_lazy_init_name_hash(struct index_state *istate, int try_threaded)
+{
+	lazy_nr_dir_threads = 0;
+	lazy_try_threaded = try_threaded;
+
+	lazy_init_name_hash(istate);
+
+	return lazy_nr_dir_threads;
 }
 
 void add_name_hash(struct index_state *istate, struct cache_entry *ce)
@@ -137,7 +630,7 @@ void remove_name_hash(struct index_state *istate, struct cache_entry *ce)
 	if (!istate->name_hash_initialized || !(ce->ce_flags & CE_HASHED))
 		return;
 	ce->ce_flags &= ~CE_HASHED;
-	hashmap_remove(&istate->name_hash, ce, ce);
+	hashmap_remove(&istate->name_hash, &ce->ent, ce);
 
 	if (ignore_case)
 		remove_dir_entry(istate, ce);
@@ -201,12 +694,12 @@ void adjust_dirname_case(struct index_state *istate, char *name)
 		if (*ptr == '/') {
 			struct dir_entry *dir;
 
-			ptr++;
-			dir = find_dir_entry(istate, name, ptr - name + 1);
+			dir = find_dir_entry(istate, name, ptr - name);
 			if (dir) {
 				memcpy((void *)startPtr, dir->name + (startPtr - name), ptr - startPtr);
-				startPtr = ptr;
+				startPtr = ptr + 1;
 			}
+			ptr++;
 		}
 	}
 }
@@ -214,15 +707,15 @@ void adjust_dirname_case(struct index_state *istate, char *name)
 struct cache_entry *index_file_exists(struct index_state *istate, const char *name, int namelen, int icase)
 {
 	struct cache_entry *ce;
+	unsigned int hash = memihash(name, namelen);
 
 	lazy_init_name_hash(istate);
 
-	ce = hashmap_get_from_hash(&istate->name_hash,
-				   memihash(name, namelen), NULL);
-	while (ce) {
+	ce = hashmap_get_entry_from_hash(&istate->name_hash, hash, NULL,
+					 struct cache_entry, ent);
+	hashmap_for_each_entry_from(&istate->name_hash, ce, ent) {
 		if (same_name(ce, name, namelen, icase))
 			return ce;
-		ce = hashmap_get_next(&istate->name_hash, ce);
 	}
 	return NULL;
 }
@@ -233,6 +726,6 @@ void free_name_hash(struct index_state *istate)
 		return;
 	istate->name_hash_initialized = 0;
 
-	hashmap_free(&istate->name_hash, 0);
-	hashmap_free(&istate->dir_hash, 1);
+	hashmap_clear(&istate->name_hash);
+	hashmap_clear_and_free(&istate->dir_hash, struct dir_entry, ent);
 }