Unify the hash function of cache and map #249
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jserv
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Consider the following macro:
/* This hashing routine is adapted from Linux kernel.
* See
* https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/tree/include/linux/hash.h
*/
#define HASH_FUNC_IMPL(name, size_bits, size) \
FORCE_INLINE uint32_t name(uint32_t val) \
{ \
/* 0x61C88647 is 32-bit golden ratio */ \
return (val * 0x61C88647 >> (32 - size_bits)) & (size - 1); \
}It should appear in src/utils.h and be used in C source files. For example,
HASH_FUNC_IMPL(hash, cache_size_bis, cache_size)
Based on the below performance analysis, the golden ratio hash is a little bit better than map hash. Therefore, we unify the hash function to golden ratio hash. |Metric | map hash | golden ratio hash | |----------+----------+-------------------| |Dhrystone | 2.06 s| 2.07 s | |Nqueens | 4.35 s| 4.25 s | |Stream | 76.7 s| 75.59 s |
vestata
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Unify the hash function of cache and map
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Based on the below performance analysis, the golden ratio hash is a little bit better than map hash. Therefore, we unify the hash function to golden ratio hash.
Close: #149