diff options
| author | Ran Benita <ran@unusedvar.com> | 2021-04-01 22:46:56 +0300 |
|---|---|---|
| committer | Ran Benita <ran@unusedvar.com> | 2021-04-01 22:52:59 +0300 |
| commit | 45b1ca22052b79c83bd96b7c5828add156768b8e (patch) | |
| tree | d24d9e793fd8d0c4cf40c07858b1e9ff75ff5f2c /scripts | |
| parent | 8cd688c06378ebdb2def6f310fb1e78898b75bde (diff) | |
| download | xorg-lib-libxkbcommon-45b1ca22052b79c83bd96b7c5828add156768b8e.tar.gz | |
keysym: speed up the perfect hash function
Make it use a bit operation instead of an expensive modulo.
perf diff:
Baseline Delta Abs Shared Object Symbol
........ ......... ................. ...................................
28.15% -6.57% bench-compose [.] xkb_keysym_from_name
Signed-off-by: Ran Benita <ran@unusedvar.com>
Diffstat (limited to 'scripts')
| -rw-r--r-- | scripts/perfect_hash.py | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/scripts/perfect_hash.py b/scripts/perfect_hash.py index 0d7df42..b94ed98 100644 --- a/scripts/perfect_hash.py +++ b/scripts/perfect_hash.py @@ -195,7 +195,9 @@ class StrSaltHash(object): self.salt = '' def __call__(self, key): - while len(self.salt) < len(key): # add more salt as necessary + # XXX: xkbcommon modification: make the salt length a power of 2 + # so that the % operation in the hash is fast. + while len(self.salt) < max(len(key), 32): # add more salt as necessary self.salt += random.choice(self.chars) return sum(ord(self.salt[i]) * ord(c) |