From 458cf91cd98b71e74fce7206b60437a40d00d51c Mon Sep 17 00:00:00 2001 From: Benoit Jacob Date: Fri, 20 Feb 2015 17:08:04 -0500 Subject: Add benchmark-blocking-sizes.cpp to bench/ per mailing list discussion. --- bench/benchmark-blocking-sizes.cpp | 356 +++++++++++++++++++++++++++++++++++++ 1 file changed, 356 insertions(+) create mode 100644 bench/benchmark-blocking-sizes.cpp diff --git a/bench/benchmark-blocking-sizes.cpp b/bench/benchmark-blocking-sizes.cpp new file mode 100644 index 000000000..04244575a --- /dev/null +++ b/bench/benchmark-blocking-sizes.cpp @@ -0,0 +1,356 @@ +#include +#include +#include +#include +#include + +int eigen_block_size_k, eigen_block_size_m, eigen_block_size_n; +#define EIGEN_TEST_SPECIFIC_BLOCKING_SIZES +#define EIGEN_TEST_SPECIFIC_BLOCKING_SIZE_K eigen_block_size_k +#define EIGEN_TEST_SPECIFIC_BLOCKING_SIZE_M eigen_block_size_m +#define EIGEN_TEST_SPECIFIC_BLOCKING_SIZE_N eigen_block_size_n +#include + +#include + +using namespace Eigen; +using namespace std; + +static BenchTimer timer; + +// how many times we repeat each measurement. +// measurements are randomly shuffled - we're not doing +// all N identical measurements in a row. +const int measurement_repetitions = 3; + +// Timings below this value are too short to be accurate, +// we'll repeat measurements with more iterations until +// we get a timing above that threshold. +const float min_accurate_time = 1e-2f; + +// See --min-working-set-size command line parameter. +size_t min_working_set_size = 0; + +// range of sizes that we will benchmark (in all 3 K,M,N dimensions) +const size_t maxsize = 2048; +const size_t minsize = 16; + +typedef MatrixXf MatrixType; + +static_assert((maxsize & (maxsize - 1)) == 0, "maxsize must be a power of two"); +static_assert((minsize & (minsize - 1)) == 0, "minsize must be a power of two"); +static_assert(maxsize > minsize, "maxsize must be larger than minsize"); +static_assert(maxsize < (minsize << 16), "maxsize must be less than (minsize<<16)"); + +// just a helper to store a triple of K,M,N sizes for matrix product +struct size_triple_t +{ + size_t k, m, n; + size_triple_t() : k(0), m(0), n(0) {} + size_triple_t(size_t _k, size_t _m, size_t _n) : k(_k), m(_m), n(_n) {} + size_triple_t(const size_triple_t& o) : k(o.k), m(o.m), n(o.n) {} + size_triple_t(uint16_t compact) + { + k = 1 << ((compact & 0xf00) >> 8); + m = 1 << ((compact & 0x0f0) >> 4); + n = 1 << ((compact & 0x00f) >> 0); + } +}; + +uint8_t log2_pot(size_t x) { + size_t l = 0; + while (x >>= 1) l++; + return l; +} + +// Convert between size tripes and a compact form fitting in 12 bits +// where each size, which must be a POT, is encoded as its log2, on 4 bits +// so the largest representable size is 2^15 == 32k ... big enough. +uint16_t compact_size_triple(size_t k, size_t m, size_t n) +{ + return (log2_pot(k) << 8) | (log2_pot(m) << 4) | log2_pot(n); +} + +uint16_t compact_size_triple(const size_triple_t& t) +{ + return compact_size_triple(t.k, t.m, t.n); +} + +// A single benchmark. Initially only contains benchmark params. +// Then call run(), which stores the result in the gflops field. +struct benchmark_t +{ + uint16_t compact_product_size; + uint16_t compact_block_size; + float gflops; + benchmark_t() + : compact_product_size(0) + , compact_block_size(0) + , gflops(0) + {} + benchmark_t(size_t pk, size_t pm, size_t pn, + size_t bk, size_t bm, size_t bn) + : compact_product_size(compact_size_triple(pk, pm, pn)) + , compact_block_size(compact_size_triple(bk, bm, bn)) + , gflops(0) + {} + + void run(); +}; + +ostream& operator<<(ostream& s, const benchmark_t& b) +{ + s << hex; + s << b.compact_product_size + << " " << b.compact_block_size; + s << dec; + s << " " << b.gflops; + return s; +} + +// We sort first by increasing benchmark parameters, +// then by decreasing performance. +bool operator<(const benchmark_t& b1, const benchmark_t& b2) +{ + return b1.compact_product_size < b2.compact_product_size || + (b1.compact_product_size == b2.compact_product_size && ( + (b1.compact_block_size < b2.compact_block_size || ( + b1.compact_block_size == b2.compact_block_size && + b1.gflops > b2.gflops)))); +} + +void benchmark_t::run() +{ + // expand our compact benchmark params into proper triples + size_triple_t productsizes(compact_product_size); + size_triple_t blocksizes(compact_block_size); + + // feed eigen with our custom blocking params + eigen_block_size_k = blocksizes.k; + eigen_block_size_m = blocksizes.m; + eigen_block_size_n = blocksizes.n; + + // set up the matrix pool + + const size_t combined_three_matrices_sizes = + sizeof(MatrixType::Scalar) * + (productsizes.k * productsizes.m + + productsizes.k * productsizes.n + + productsizes.m * productsizes.n); + + // 64 M is large enough that nobody has a cache bigger than that, + // while still being small enough that everybody has this much RAM, + // so conveniently we don't need to special-case platforms here. + const size_t unlikely_large_cache_size = 64 << 20; + + const size_t working_set_size = + min_working_set_size ? min_working_set_size : unlikely_large_cache_size; + + const size_t matrix_pool_size = + 1 + working_set_size / combined_three_matrices_sizes; + + MatrixType *lhs = new MatrixType[matrix_pool_size]; + MatrixType *rhs = new MatrixType[matrix_pool_size]; + MatrixType *dst = new MatrixType[matrix_pool_size]; + + for (size_t i = 0; i < matrix_pool_size; i++) { + lhs[i] = MatrixType::Zero(productsizes.m, productsizes.k); + rhs[i] = MatrixType::Zero(productsizes.k, productsizes.n); + dst[i] = MatrixType::Zero(productsizes.m, productsizes.n); + } + + // main benchmark loop + + int iters_at_a_time = 1; + float time_per_iter = 0.0f; + size_t matrix_index = 0; + while (true) { + + double starttime = timer.getCpuTime(); + for (int i = 0; i < iters_at_a_time; i++) { + dst[matrix_index] = lhs[matrix_index] * rhs[matrix_index]; + matrix_index++; + if (matrix_index == matrix_pool_size) { + matrix_index = 0; + } + } + double endtime = timer.getCpuTime(); + + const float timing = float(endtime - starttime); + + if (timing >= min_accurate_time) { + time_per_iter = timing / iters_at_a_time; + break; + } + + iters_at_a_time *= 2; + } + + delete[] lhs; + delete[] rhs; + delete[] dst; + + gflops = 2e-9 * productsizes.k * productsizes.m * productsizes.n / time_per_iter; +} + +void print_cpuinfo() +{ +#ifdef __linux__ + cout << "contents of /proc/cpuinfo:" << endl; + string line; + ifstream cpuinfo("/proc/cpuinfo"); + if (cpuinfo.is_open()) { + while (getline(cpuinfo, line)) { + cout << line << endl; + } + cpuinfo.close(); + } + cout << endl; +#elif defined __APPLE__ + cout << "output of sysctl hw:" << endl; + system("sysctl hw"); + cout << endl; +#endif +} + +template +string type_name() +{ + return "unknown"; +} + +template<> +string type_name() +{ + return "float"; +} + +template<> +string type_name() +{ + return "double"; +} + +void show_usage_and_exit(const char *progname) +{ + cerr << "usage: " << progname << " [--min-working-set-size=N]" << endl << endl; + cerr << " --min-working-set-size=N:" << endl; + cerr << " Set the minimum working set size to N bytes." << endl; + cerr << " This is rounded up as needed to a multiple of matrix size." << endl; + cerr << " A larger working set lowers the chance of a warm cache." << endl; + cerr << " The default value 0 means use a large enough working" << endl; + cerr << " set to likely outsize caches." << endl; + cerr << " A value of 1 (that is, 1 byte) would mean don't do anything to" << endl; + cerr << " avoid warm caches." << endl; + exit(1); +} + +int main(int argc, char* argv[]) +{ + for (int i = 1; i < argc; i++) { + if (argv[i] == strstr(argv[i], "--min-working-set-size=")) { + const char* equals_sign = strchr(argv[i], '='); + min_working_set_size = strtoul(equals_sign+1, nullptr, 10); + } else { + cerr << "unrecognized option: " << argv[i] << endl << endl; + show_usage_and_exit(argv[0]); + } + } + + cout.precision(4); + + print_cpuinfo(); + + cout << "benchmark parameters:" << endl; + cout << "pointer size: " << 8*sizeof(void*) << " bits" << endl; + cout << "scalar type: " << type_name() << endl; + cout << "packet size: " << internal::packet_traits::size << endl; + cout << "minsize = " << minsize << endl; + cout << "maxsize = " << maxsize << endl; + cout << "measurement_repetitions = " << measurement_repetitions << endl; + cout << "min_accurate_time = " << min_accurate_time << endl; + cout << "min_working_set_size = " << min_working_set_size; + if (min_working_set_size == 0) { + cout << " (try to outsize caches)"; + } + cout << endl << endl; + + + // assemble the array of benchmarks without running them at first + vector benchmarks; + for (int repetition = 0; repetition < measurement_repetitions; repetition++) { + for (size_t ksize = minsize; ksize <= maxsize; ksize *= 2) { + for (size_t msize = minsize; msize <= maxsize; msize *= 2) { + for (size_t nsize = minsize; nsize <= maxsize; nsize *= 2) { + for (size_t kblock = minsize; kblock <= ksize; kblock *= 2) { + for (size_t mblock = minsize; mblock <= msize; mblock *= 2) { + for (size_t nblock = minsize; nblock <= nsize; nblock *= 2) { + benchmark_t b(ksize, msize, nsize, kblock, mblock, nblock); + benchmarks.push_back(b); + } + } + } + } + } + } + } + + // randomly shuffling benchmarks allows us to get accurate enough progress info, + // as now the cheap/expensive benchmarks are randomly mixed so they average out. + random_shuffle(benchmarks.begin(), benchmarks.end()); + + // timings here are only used to display progress info. + // Whence the use of real time. + double time_start = timer.getRealTime(); + double time_last_progress_update = time_start; + for (size_t i = 0; i < benchmarks.size(); i++) { + // Display progress info on stderr + double time_now = timer.getRealTime(); + if (time_now > time_last_progress_update + 1.0f) { + time_last_progress_update = time_now; + float ratio_done = float(i) / benchmarks.size(); + cerr.precision(3); + cerr << "Measurements... " << 100.0f * ratio_done + << " %"; + + if (i > 10) { + cerr << ", ETA "; + float eta = float(time_now - time_start) * (1.0f - ratio_done) / ratio_done; + if (eta > 3600) + cerr << eta/3600 << " hours"; + else if (eta > 60) + cerr << eta/60 << " minutes"; + else cerr << eta << " seconds"; + } + cerr << " \r" << flush; + } + + // This is where we actually run a benchmark! + benchmarks[i].run(); + } + + // Erase progress info + cerr << " " << endl; + + // Sort timings by increasing benchmark parameters, and decreasing gflops. + // The latter is very important. It means that we can ignore all but the first + // benchmark with given parameters. + sort(benchmarks.begin(), benchmarks.end()); + + // Collect best (i.e. now first) results for each parameter values. + vector best_benchmarks; + for (auto it = benchmarks.begin(); it != benchmarks.end(); ++it) { + if (best_benchmarks.empty() || + best_benchmarks.back().compact_product_size != it->compact_product_size || + best_benchmarks.back().compact_block_size != it->compact_block_size) + { + best_benchmarks.push_back(*it); + } + } + + // Output data. + cout << "BEGIN MEASUREMENTS" << endl; + for (auto it = best_benchmarks.begin(); it != best_benchmarks.end(); ++it) { + cout << *it << endl; + } +} -- cgit v1.2.3