From 58ef70227a0c5591710d51af76b4c6cad77ee2e4 Mon Sep 17 00:00:00 2001 From: Willy Tarreau Date: Tue, 8 May 2007 23:22:43 +0200 Subject: [PATCH] [TESTS] added a trivial program to benchmark hash algos The uri_hash.c program makes it very easy to benchmark the distribution of hash algos. Pass it one word per line, and it will show the distribution per server for 1 to 10 servers. --- tests/uri_hash.c | 228 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 228 insertions(+) create mode 100644 tests/uri_hash.c diff --git a/tests/uri_hash.c b/tests/uri_hash.c new file mode 100644 index 0000000000..4fc1f9f58d --- /dev/null +++ b/tests/uri_hash.c @@ -0,0 +1,228 @@ +#include + +#define NSERV 10 +#define MAXLINE 1000 + +char line[MAXLINE]; + +int counts_gd1[NSERV][NSERV]; +static unsigned long hash_gd1(char *uri) +{ + unsigned long hash = 0; + int c; + + while (c = *uri++) + hash = c + (hash << 6) + (hash << 16) - hash; + + return hash; +} + +int counts_gd2[NSERV][NSERV]; +static unsigned long hash_gd2(char *uri) +{ + unsigned long hash = 0; + int c; + + while (c = *uri++) { + if (c == '?' || c == '\n') + break; + hash = c + (hash << 6) + (hash << 16) - hash; + } + + return hash; +} + + +int counts_gd3[NSERV][NSERV]; +static unsigned long hash_gd3(char *uri) +{ + unsigned long hash = 0; + int c; + + while (c = *uri++) { + if (c == '?' || c == '\n') + break; + hash = c - (hash << 3) + (hash << 15) - hash; + } + + return hash; +} + + +int counts_gd4[NSERV][NSERV]; +static unsigned long hash_gd4(char *uri) +{ + unsigned long hash = 0; + int c; + + while (c = *uri++) { + if (c == '?' || c == '\n') + break; + hash = hash + (hash << 6) - (hash << 15) - c; + } + + return hash; +} + + +int counts_gd5[NSERV][NSERV]; +static unsigned long hash_gd5(char *uri) +{ + unsigned long hash = 0; + int c; + + while (c = *uri++) { + if (c == '?' || c == '\n') + break; + hash = hash + (hash << 2) - (hash << 19) - c; + } + + return hash; +} + + +int counts_gd6[NSERV][NSERV]; +static unsigned long hash_gd6(char *uri) +{ + unsigned long hash = 0; + int c; + + while (c = *uri++) { + if (c == '?' || c == '\n') + break; + hash = hash + (hash << 2) - (hash << 22) - c; + } + + return hash; +} + + +int counts_wt1[NSERV][NSERV]; +static unsigned long hash_wt1(int hsize, char *string) { + int bits; + unsigned long data, val; + + bits = val = data = 0; + while (*string) { + if (*string == '?' || *string == '\n') + break; + data |= ((unsigned long)(unsigned char)*string) << bits; + bits += 8; + while (bits >= hsize) { + val ^= data - (val >> hsize); + bits -= hsize; + data >>= hsize; + } + string++; + } + val ^= data; + while (val > ((1 << hsize) - 1)) { + val = (val & ((1 << hsize) - 1)) ^ (val >> hsize); + } + return val; +} + +/* + * efficient hash : no duplicate on the first 65536 values of 2 bytes. + * less than 0.1% duplicates for the first 1.6 M values of 3 bytes. + */ +int counts_wt2[NSERV][NSERV]; +typedef unsigned int u_int32_t; + +static inline u_int32_t shl32(u_int32_t i, int count) { + if (count == 32) + return 0; + return i << count; +} + +static inline u_int32_t shr32(u_int32_t i, int count) { + if (count == 32) + return 0; + return i >> count; +} + +static unsigned int rev32(unsigned int c) { + c = ((c & 0x0000FFFF) << 16)| ((c & 0xFFFF0000) >> 16); + c = ((c & 0x00FF00FF) << 8) | ((c & 0xFF00FF00) >> 8); + c = ((c & 0x0F0F0F0F) << 4) | ((c & 0xF0F0F0F0) >> 4); + c = ((c & 0x33333333) << 2) | ((c & 0xCCCCCCCC) >> 2); + c = ((c & 0x55555555) << 1) | ((c & 0xAAAAAAAA) >> 1); + return c; +} + +int hash_wt2(const char *src, int len) { + unsigned int i = 0x3C964BA5; /* as many ones as zeroes */ + unsigned int j, k; + unsigned int ih, il; + int bit; + + while (len--) { + j = (unsigned char)*src++; + if (j == '?' || j == '\n') + break; + bit = rev32(j - i); + bit = bit - (bit >> 3) + (bit >> 16) - j; + + bit &= 0x1f; + ih = shr32(i, bit); + il = i & (shl32(1, bit) - 1); + i = shl32(il, 32-bit) - ih - ~j; + } + return i; +} + +void count_hash_results(unsigned long hash, int counts[NSERV][NSERV]) { + int srv, nsrv; + + for (nsrv = 0; nsrv < NSERV; nsrv++) { + srv = hash % (nsrv + 1); + counts[nsrv][srv]++; + } +} + +void dump_hash_results(char *name, int counts[NSERV][NSERV]) { + int srv, nsrv; + + printf("%s:\n", name); + for (nsrv = 0; nsrv < NSERV; nsrv++) { + printf("%02d srv: ", nsrv+1); + for (srv = 0; srv <= nsrv; srv++) { + //printf("%6d ", counts[nsrv][srv]); + //printf("%3.1f ", (100.0*counts[nsrv][srv]) / (double)counts[0][0]); + printf("%3.1f ", 100.0*(counts[nsrv][srv] - (double)counts[0][0]/(nsrv+1)) / (double)counts[0][0]); + } + printf("\n"); + } + printf("\n"); +} + +main() { + memset(counts_gd1, 0, sizeof(counts_gd1)); + memset(counts_gd2, 0, sizeof(counts_gd2)); + memset(counts_gd3, 0, sizeof(counts_gd3)); + memset(counts_gd4, 0, sizeof(counts_gd4)); + memset(counts_gd5, 0, sizeof(counts_gd5)); + memset(counts_gd6, 0, sizeof(counts_gd6)); + memset(counts_wt1, 0, sizeof(counts_wt1)); + memset(counts_wt2, 0, sizeof(counts_wt2)); + + while (fgets(line, MAXLINE, stdin) != NULL) { + count_hash_results(hash_gd1(line), counts_gd1); + count_hash_results(hash_gd2(line), counts_gd2); + count_hash_results(hash_gd3(line), counts_gd3); + count_hash_results(hash_gd4(line), counts_gd4); + count_hash_results(hash_gd5(line), counts_gd5); + count_hash_results(hash_gd6(line), counts_gd6); + count_hash_results(hash_wt1(31, line), counts_wt1); + count_hash_results(hash_wt2(line, strlen(line)), counts_wt2); + } + + dump_hash_results("hash_gd1", counts_gd1); + dump_hash_results("hash_gd2", counts_gd2); + dump_hash_results("hash_gd3", counts_gd3); + dump_hash_results("hash_gd4", counts_gd4); + dump_hash_results("hash_gd5", counts_gd5); + dump_hash_results("hash_gd6", counts_gd6); + dump_hash_results("hash_wt1", counts_wt1); + dump_hash_results("hash_wt2", counts_wt2); +}