X-Git-Url: https://git.kernel.dk/?p=fio.git;a=blobdiff_plain;f=lib%2Frand.c;h=46ffe4fb0c6b9108685254cbe7f110983eb27088;hp=b8d8f78d31fb13893d1ee879f84922ccc28cd5a5;hb=83742c72e3d69b2d5c8a890b3803042b5fd1aae0;hpb=7e744013dca36be3840c45d13f4ae09947282bea diff --git a/lib/rand.c b/lib/rand.c index b8d8f78d..46ffe4fb 100644 --- a/lib/rand.c +++ b/lib/rand.c @@ -1,24 +1,198 @@ +/* + This is a maximally equidistributed combined Tausworthe generator + based on code from GNU Scientific Library 1.5 (30 Jun 2004) + + x_n = (s1_n ^ s2_n ^ s3_n) + + s1_{n+1} = (((s1_n & 4294967294) <<12) ^ (((s1_n <<13) ^ s1_n) >>19)) + s2_{n+1} = (((s2_n & 4294967288) << 4) ^ (((s2_n << 2) ^ s2_n) >>25)) + s3_{n+1} = (((s3_n & 4294967280) <<17) ^ (((s3_n << 3) ^ s3_n) >>11)) + + The period of this generator is about 2^88. + + From: P. L'Ecuyer, "Maximally Equidistributed Combined Tausworthe + Generators", Mathematics of Computation, 65, 213 (1996), 203--213. + + This is available on the net from L'Ecuyer's home page, + + http://www.iro.umontreal.ca/~lecuyer/myftp/papers/tausme.ps + ftp://ftp.iro.umontreal.ca/pub/simulation/lecuyer/papers/tausme.ps + + There is an erratum in the paper "Tables of Maximally + Equidistributed Combined LFSR Generators", Mathematics of + Computation, 68, 225 (1999), 261--269: + http://www.iro.umontreal.ca/~lecuyer/myftp/papers/tausme2.ps + + ... the k_j most significant bits of z_j must be non- + zero, for each j. (Note: this restriction also applies to the + computer code given in [4], but was mistakenly not mentioned in + that paper.) + + This affects the seeding procedure by imposing the requirement + s1 > 1, s2 > 7, s3 > 15. + +*/ + +#include #include "rand.h" +#include "pattern.h" +#include "../hash.h" -struct frand_state __fio_rand_state; +int arch_random; -static inline int __seed(unsigned int x, unsigned int m) +static inline uint64_t __seed(uint64_t x, uint64_t m) { return (x < m) ? x + m : x; } -void init_rand(struct frand_state *state) +static void __init_rand32(struct taus88_state *state, unsigned int seed) +{ + int cranks = 6; + +#define LCG(x, seed) ((x) * 69069 ^ (seed)) + + state->s1 = __seed(LCG((2^31) + (2^17) + (2^7), seed), 1); + state->s2 = __seed(LCG(state->s1, seed), 7); + state->s3 = __seed(LCG(state->s2, seed), 15); + + while (cranks--) + __rand32(state); +} + +static void __init_rand64(struct taus258_state *state, uint64_t seed) +{ + int cranks = 6; + +#define LCG64(x, seed) ((x) * 6906969069ULL ^ (seed)) + + state->s1 = __seed(LCG64((2^31) + (2^17) + (2^7), seed), 1); + state->s2 = __seed(LCG64(state->s1, seed), 7); + state->s3 = __seed(LCG64(state->s2, seed), 15); + state->s4 = __seed(LCG64(state->s3, seed), 33); + state->s5 = __seed(LCG64(state->s4, seed), 49); + + while (cranks--) + __rand64(state); +} + +void init_rand(struct frand_state *state, bool use64) +{ + state->use64 = use64; + + if (!use64) + __init_rand32(&state->state32, 1); + else + __init_rand64(&state->state64, 1); +} + +void init_rand_seed(struct frand_state *state, unsigned int seed, bool use64) +{ + state->use64 = use64; + + if (!use64) + __init_rand32(&state->state32, seed); + else + __init_rand64(&state->state64, seed); +} + +void __fill_random_buf(void *buf, unsigned int len, unsigned long seed) +{ + void *ptr = buf; + + while (len) { + int this_len; + + if (len >= sizeof(int64_t)) { + *((int64_t *) ptr) = seed; + this_len = sizeof(int64_t); + } else if (len >= sizeof(int32_t)) { + *((int32_t *) ptr) = seed; + this_len = sizeof(int32_t); + } else if (len >= sizeof(int16_t)) { + *((int16_t *) ptr) = seed; + this_len = sizeof(int16_t); + } else { + *((int8_t *) ptr) = seed; + this_len = sizeof(int8_t); + } + ptr += this_len; + len -= this_len; + seed *= GOLDEN_RATIO_PRIME; + seed >>= 3; + } +} + +unsigned long fill_random_buf(struct frand_state *fs, void *buf, + unsigned int len) +{ + unsigned long r = __rand(fs); + + if (sizeof(int) != sizeof(long *)) + r *= (unsigned long) __rand(fs); + + __fill_random_buf(buf, len, r); + return r; +} + +void __fill_random_buf_percentage(unsigned long seed, void *buf, + unsigned int percentage, + unsigned int segment, unsigned int len, + char *pattern, unsigned int pbytes) +{ + unsigned int this_len; + + if (percentage == 100) { + if (pbytes) + (void)cpy_pattern(pattern, pbytes, buf, len); + else + memset(buf, 0, len); + return; + } + + if (segment > len) + segment = len; + + while (len) { + /* + * Fill random chunk + */ + this_len = (segment * (100 - percentage)) / 100; + if (this_len > len) + this_len = len; + + __fill_random_buf(buf, this_len, seed); + + len -= this_len; + if (!len) + break; + buf += this_len; + + if (this_len > len) + this_len = len; + else if (len - this_len <= sizeof(long)) + this_len = len; + + if (pbytes) + (void)cpy_pattern(pattern, pbytes, buf, this_len); + else + memset(buf, 0, this_len); + + len -= this_len; + buf += this_len; + } +} + +unsigned long fill_random_buf_percentage(struct frand_state *fs, void *buf, + unsigned int percentage, + unsigned int segment, unsigned int len, + char *pattern, unsigned int pbytes) { -#define LCG(x) ((x) * 69069) /* super-duper LCG */ + unsigned long r = __rand(fs); - state->s1 = __seed(LCG((2^31) + (2^17) + (2^7)), 1); - state->s2 = __seed(LCG(state->s1), 7); - state->s3 = __seed(LCG(state->s2), 15); + if (sizeof(int) != sizeof(long *)) + r *= (unsigned long) __rand(fs); - __rand(state); - __rand(state); - __rand(state); - __rand(state); - __rand(state); - __rand(state); + __fill_random_buf_percentage(r, buf, percentage, segment, len, + pattern, pbytes); + return r; }