diff options
author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-14 13:40:54 +0000 |
---|---|---|
committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-14 13:40:54 +0000 |
commit | 317c0644ccf108aa23ef3fd8358bd66c2840bfc0 (patch) | |
tree | c417b3d25c86b775989cb5ac042f37611b626c8a /deps/jemalloc/test/analyze/rand.c | |
parent | Initial commit. (diff) | |
download | redis-317c0644ccf108aa23ef3fd8358bd66c2840bfc0.tar.xz redis-317c0644ccf108aa23ef3fd8358bd66c2840bfc0.zip |
Adding upstream version 5:7.2.4.upstream/5%7.2.4
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'deps/jemalloc/test/analyze/rand.c')
-rw-r--r-- | deps/jemalloc/test/analyze/rand.c | 276 |
1 files changed, 276 insertions, 0 deletions
diff --git a/deps/jemalloc/test/analyze/rand.c b/deps/jemalloc/test/analyze/rand.c new file mode 100644 index 0000000..bb20b06 --- /dev/null +++ b/deps/jemalloc/test/analyze/rand.c @@ -0,0 +1,276 @@ +#include "test/jemalloc_test.h" + +/******************************************************************************/ + +/* + * General purpose tool for examining random number distributions. + * + * Input - + * (a) a random number generator, and + * (b) the buckets: + * (1) number of buckets, + * (2) width of each bucket, in log scale, + * (3) expected mean and stddev of the count of random numbers in each + * bucket, and + * (c) number of iterations to invoke the generator. + * + * The program generates the specified amount of random numbers, and assess how + * well they conform to the expectations: for each bucket, output - + * (a) the (given) expected mean and stddev, + * (b) the actual count and any interesting level of deviation: + * (1) ~68% buckets should show no interesting deviation, meaning a + * deviation less than stddev from the expectation; + * (2) ~27% buckets should show '+' / '-', meaning a deviation in the range + * of [stddev, 2 * stddev) from the expectation; + * (3) ~4% buckets should show '++' / '--', meaning a deviation in the + * range of [2 * stddev, 3 * stddev) from the expectation; and + * (4) less than 0.3% buckets should show more than two '+'s / '-'s. + * + * Technical remarks: + * (a) The generator is expected to output uint64_t numbers, so you might need + * to define a wrapper. + * (b) The buckets must be of equal width and the lowest bucket starts at + * [0, 2^lg_bucket_width - 1). + * (c) Any generated number >= n_bucket * 2^lg_bucket_width will be counted + * towards the last bucket; the expected mean and stddev provided should + * also reflect that. + * (d) The number of iterations is advised to be determined so that the bucket + * with the minimal expected proportion gets a sufficient count. + */ + +static void +fill(size_t a[], const size_t n, const size_t k) { + for (size_t i = 0; i < n; ++i) { + a[i] = k; + } +} + +static void +collect_buckets(uint64_t (*gen)(void *), void *opaque, size_t buckets[], + const size_t n_bucket, const size_t lg_bucket_width, const size_t n_iter) { + for (size_t i = 0; i < n_iter; ++i) { + uint64_t num = gen(opaque); + uint64_t bucket_id = num >> lg_bucket_width; + if (bucket_id >= n_bucket) { + bucket_id = n_bucket - 1; + } + ++buckets[bucket_id]; + } +} + +static void +print_buckets(const size_t buckets[], const size_t means[], + const size_t stddevs[], const size_t n_bucket) { + for (size_t i = 0; i < n_bucket; ++i) { + malloc_printf("%zu:\tmean = %zu,\tstddev = %zu,\tbucket = %zu", + i, means[i], stddevs[i], buckets[i]); + + /* Make sure there's no overflow. */ + assert(buckets[i] + stddevs[i] >= stddevs[i]); + assert(means[i] + stddevs[i] >= stddevs[i]); + + if (buckets[i] + stddevs[i] <= means[i]) { + malloc_write(" "); + for (size_t t = means[i] - buckets[i]; t >= stddevs[i]; + t -= stddevs[i]) { + malloc_write("-"); + } + } else if (buckets[i] >= means[i] + stddevs[i]) { + malloc_write(" "); + for (size_t t = buckets[i] - means[i]; t >= stddevs[i]; + t -= stddevs[i]) { + malloc_write("+"); + } + } + malloc_write("\n"); + } +} + +static void +bucket_analysis(uint64_t (*gen)(void *), void *opaque, size_t buckets[], + const size_t means[], const size_t stddevs[], const size_t n_bucket, + const size_t lg_bucket_width, const size_t n_iter) { + for (size_t i = 1; i <= 3; ++i) { + malloc_printf("round %zu\n", i); + fill(buckets, n_bucket, 0); + collect_buckets(gen, opaque, buckets, n_bucket, + lg_bucket_width, n_iter); + print_buckets(buckets, means, stddevs, n_bucket); + } +} + +/* (Recommended) minimal bucket mean. */ +#define MIN_BUCKET_MEAN 10000 + +/******************************************************************************/ + +/* Uniform random number generator. */ + +typedef struct uniform_gen_arg_s uniform_gen_arg_t; +struct uniform_gen_arg_s { + uint64_t state; + const unsigned lg_range; +}; + +static uint64_t +uniform_gen(void *opaque) { + uniform_gen_arg_t *arg = (uniform_gen_arg_t *)opaque; + return prng_lg_range_u64(&arg->state, arg->lg_range); +} + +TEST_BEGIN(test_uniform) { +#define LG_N_BUCKET 5 +#define N_BUCKET (1 << LG_N_BUCKET) + +#define QUOTIENT_CEIL(n, d) (((n) - 1) / (d) + 1) + + const unsigned lg_range_test = 25; + + /* + * Mathematical tricks to guarantee that both mean and stddev are + * integers, and that the minimal bucket mean is at least + * MIN_BUCKET_MEAN. + */ + const size_t q = 1 << QUOTIENT_CEIL(LG_CEIL(QUOTIENT_CEIL( + MIN_BUCKET_MEAN, N_BUCKET * (N_BUCKET - 1))), 2); + const size_t stddev = (N_BUCKET - 1) * q; + const size_t mean = N_BUCKET * stddev * q; + const size_t n_iter = N_BUCKET * mean; + + size_t means[N_BUCKET]; + fill(means, N_BUCKET, mean); + size_t stddevs[N_BUCKET]; + fill(stddevs, N_BUCKET, stddev); + + uniform_gen_arg_t arg = {(uint64_t)(uintptr_t)&lg_range_test, + lg_range_test}; + size_t buckets[N_BUCKET]; + assert_zu_ge(lg_range_test, LG_N_BUCKET, ""); + const size_t lg_bucket_width = lg_range_test - LG_N_BUCKET; + + bucket_analysis(uniform_gen, &arg, buckets, means, stddevs, + N_BUCKET, lg_bucket_width, n_iter); + +#undef LG_N_BUCKET +#undef N_BUCKET +#undef QUOTIENT_CEIL +} +TEST_END + +/******************************************************************************/ + +/* Geometric random number generator; compiled only when prof is on. */ + +#ifdef JEMALLOC_PROF + +/* + * Fills geometric proportions and returns the minimal proportion. See + * comments in test_prof_sample for explanations for n_divide. + */ +static double +fill_geometric_proportions(double proportions[], const size_t n_bucket, + const size_t n_divide) { + assert(n_bucket > 0); + assert(n_divide > 0); + double x = 1.; + for (size_t i = 0; i < n_bucket; ++i) { + if (i == n_bucket - 1) { + proportions[i] = x; + } else { + double y = x * exp(-1. / n_divide); + proportions[i] = x - y; + x = y; + } + } + /* + * The minimal proportion is the smaller one of the last two + * proportions for geometric distribution. + */ + double min_proportion = proportions[n_bucket - 1]; + if (n_bucket >= 2 && proportions[n_bucket - 2] < min_proportion) { + min_proportion = proportions[n_bucket - 2]; + } + return min_proportion; +} + +static size_t +round_to_nearest(const double x) { + return (size_t)(x + .5); +} + +static void +fill_references(size_t means[], size_t stddevs[], const double proportions[], + const size_t n_bucket, const size_t n_iter) { + for (size_t i = 0; i < n_bucket; ++i) { + double x = n_iter * proportions[i]; + means[i] = round_to_nearest(x); + stddevs[i] = round_to_nearest(sqrt(x * (1. - proportions[i]))); + } +} + +static uint64_t +prof_sample_gen(void *opaque) { + return prof_sample_new_event_wait((tsd_t *)opaque) - 1; +} + +#endif /* JEMALLOC_PROF */ + +TEST_BEGIN(test_prof_sample) { + test_skip_if(!config_prof); +#ifdef JEMALLOC_PROF + +/* Number of divisions within [0, mean). */ +#define LG_N_DIVIDE 3 +#define N_DIVIDE (1 << LG_N_DIVIDE) + +/* Coverage of buckets in terms of multiples of mean. */ +#define LG_N_MULTIPLY 2 +#define N_GEO_BUCKET (N_DIVIDE << LG_N_MULTIPLY) + + test_skip_if(!opt_prof); + + size_t lg_prof_sample_test = 25; + + size_t lg_prof_sample_orig = lg_prof_sample; + assert_d_eq(mallctl("prof.reset", NULL, NULL, &lg_prof_sample_test, + sizeof(size_t)), 0, ""); + malloc_printf("lg_prof_sample = %zu\n", lg_prof_sample_test); + + double proportions[N_GEO_BUCKET + 1]; + const double min_proportion = fill_geometric_proportions(proportions, + N_GEO_BUCKET + 1, N_DIVIDE); + const size_t n_iter = round_to_nearest(MIN_BUCKET_MEAN / + min_proportion); + size_t means[N_GEO_BUCKET + 1]; + size_t stddevs[N_GEO_BUCKET + 1]; + fill_references(means, stddevs, proportions, N_GEO_BUCKET + 1, n_iter); + + tsd_t *tsd = tsd_fetch(); + assert_ptr_not_null(tsd, ""); + size_t buckets[N_GEO_BUCKET + 1]; + assert_zu_ge(lg_prof_sample, LG_N_DIVIDE, ""); + const size_t lg_bucket_width = lg_prof_sample - LG_N_DIVIDE; + + bucket_analysis(prof_sample_gen, tsd, buckets, means, stddevs, + N_GEO_BUCKET + 1, lg_bucket_width, n_iter); + + assert_d_eq(mallctl("prof.reset", NULL, NULL, &lg_prof_sample_orig, + sizeof(size_t)), 0, ""); + +#undef LG_N_DIVIDE +#undef N_DIVIDE +#undef LG_N_MULTIPLY +#undef N_GEO_BUCKET + +#endif /* JEMALLOC_PROF */ +} +TEST_END + +/******************************************************************************/ + +int +main(void) { + return test_no_reentrancy( + test_uniform, + test_prof_sample); +} |