[cfe-commits] [patch] change libc++'s string hash function to cityhash64

[Craig Silverstein]

For fun, I also compared with the hash function that existed before
Howard put in murmurhash2.  It did ok! -- though cityhash is still
faster.  Normal caveats apply: this is just one dataset, and a well
behaved one at that.  Here are all the results (viewed best in a
fixed-width font):

                     orig        murmur2        cityhash64
RUN TIME -O2          9.85        10.10             8.80
COMPILE TIME -O2      1.08         1.08             1.08
BINARY SIZE -O2      31148        31257            31402

RUN_TIME             16.75        16.20            15.60
COMPILE_TIME          0.98         0.96             0.96
BINARY_SIZE          71588        (not recorded)   76608

COMPILE_TIME -g       1.22         1.27             1.21
BINARY_SIZE -g      335852       336295           346104

craig