From bbe8d51bd9ab0c848ee833000dcc93eb78bcbcad Mon Sep 17 00:00:00 2001
From: Damien George <damien.p.george@gmail.com>
Date: Sat, 26 Dec 2015 21:15:47 +0000
Subject: [PATCH] py/map: Add fast-path for hashing of map index when it is a
qstr.
Map indicies are most commonly a qstr, and adding a fast-path for hashing
of a qstr increases overall performance of the runtime.
On pyboard there is a 4% improvement in the pystone benchmark for a cost
of 20 bytes of code size. It's about a 2% improvement on unix.
---
py/map.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)
diff --git a/py/map.c b/py/map.c
index 087f320c2..7900ee1de 100644
--- a/py/map.c
+++ b/py/map.c
@@ -201,7 +201,14 @@ mp_map_elem_t *mp_map_lookup(mp_map_t *map, mp_obj_t index, mp_map_lookup_kind_t
}
}
- mp_uint_t hash = MP_OBJ_SMALL_INT_VALUE(mp_unary_op(MP_UNARY_OP_HASH, index));
+ // get hash of index, with fast path for common case of qstr
+ mp_uint_t hash;
+ if (MP_OBJ_IS_QSTR(index)) {
+ hash = qstr_hash(MP_OBJ_QSTR_VALUE(index));
+ } else {
+ hash = MP_OBJ_SMALL_INT_VALUE(mp_unary_op(MP_UNARY_OP_HASH, index));
+ }
+
mp_uint_t pos = hash % map->alloc;
mp_uint_t start_pos = pos;
mp_map_elem_t *avail_slot = NULL;
--
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