This avoids unnecessary allocations and reinsertions. On webkit.git
(i.e. about 100k inserts to the name hash table), this reduces about
100ms out of 3s user time.
treat_leading_path: 0.000 0.000
read_directory: 1.299 1.305
+treat_one_path: 0.599 0.599
++is_excluded: 0.103 0.103
+++prep_exclude: 0.040 0.040
+++matching: 0.036 0.035
++dir_exist: 0.036 0.035
++index_name_exists: 0.291 0.292
lazy_init_name_hash: 0.257 0.155
+simplify_away: 0.082 0.083
+dir_add_name: 0.000 0.000
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@xxxxxxxxx>
---
diffcore-rename.c | 1 +
hash.h | 7 +++++++
name-hash.c | 1 +
3 files changed, 9 insertions(+)
diff --git a/diffcore-rename.c b/diffcore-rename.c
index 512d0ac..8d3d9bb 100644
--- a/diffcore-rename.c
+++ b/diffcore-rename.c
@@ -389,6 +389,7 @@ static int find_exact_renames(struct diff_options *options)
struct hash_table file_table;
init_hash(&file_table);
+ preallocate_hash(&file_table, (rename_src_nr + rename_dst_nr) * 2);
for (i = 0; i < rename_src_nr; i++)
insert_file_table(&file_table, -1, i, rename_src[i].p->one);
diff --git a/hash.h b/hash.h
index b875ce6..244d1fe 100644
--- a/hash.h
+++ b/hash.h
@@ -40,4 +40,11 @@ static inline void init_hash(struct hash_table *table)
table->array = NULL;
}
+static inline void preallocate_hash(struct hash_table *table, unsigned int size)
+{
+ assert(table->size == 0 && table->nr == 0 && table->array == NULL);
+ table->size = size;
+ table->array = xcalloc(sizeof(struct hash_table_entry), size);
+}
+
#endif
diff --git a/name-hash.c b/name-hash.c
index 942c459..1287a19 100644
--- a/name-hash.c
+++ b/name-hash.c
@@ -92,6 +92,7 @@ static void lazy_init_name_hash(struct index_state *istate)
if (istate->name_hash_initialized)
return;
+ preallocate_hash(&istate->name_hash, istate->cache_nr * 2);
for (nr = 0; nr < istate->cache_nr; nr++)
hash_index_entry(istate, istate->cache[nr]);
istate->name_hash_initialized = 1;
--
1.8.1.2.536.gf441e6d
--
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