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Diffstat (limited to 'eigen/bench/benchmark-blocking-sizes.cpp')
| -rw-r--r-- | eigen/bench/benchmark-blocking-sizes.cpp | 677 |
1 files changed, 677 insertions, 0 deletions
diff --git a/eigen/bench/benchmark-blocking-sizes.cpp b/eigen/bench/benchmark-blocking-sizes.cpp new file mode 100644 index 0000000..827be28 --- /dev/null +++ b/eigen/bench/benchmark-blocking-sizes.cpp @@ -0,0 +1,677 @@ +// This file is part of Eigen, a lightweight C++ template library +// for linear algebra. +// +// Copyright (C) 2015 Benoit Jacob <benoitjacob@google.com> +// +// This Source Code Form is subject to the terms of the Mozilla +// Public License v. 2.0. If a copy of the MPL was not distributed +// with this file, You can obtain one at http://mozilla.org/MPL/2.0/. + +#include <iostream> +#include <cstdint> +#include <cstdlib> +#include <vector> +#include <fstream> +#include <memory> +#include <cstdio> + +bool eigen_use_specific_block_size; +int eigen_block_size_k, eigen_block_size_m, eigen_block_size_n; +#define EIGEN_TEST_SPECIFIC_BLOCKING_SIZES eigen_use_specific_block_size +#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 <Eigen/Core> + +#include <bench/BenchTimer.h> + +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; + +float max_clock_speed = 0.0f; + +// 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; +typedef MatrixType::Scalar Scalar; +typedef internal::packet_traits<Scalar>::type Packet; + +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; + bool use_default_block_size; + float gflops; + benchmark_t() + : compact_product_size(0) + , compact_block_size(0) + , use_default_block_size(false) + , 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)) + , use_default_block_size(false) + , gflops(0) + {} + benchmark_t(size_t pk, size_t pm, size_t pn) + : compact_product_size(compact_size_triple(pk, pm, pn)) + , compact_block_size(0) + , use_default_block_size(true) + , gflops(0) + {} + + void run(); +}; + +ostream& operator<<(ostream& s, const benchmark_t& b) +{ + s << hex << b.compact_product_size << dec; + if (b.use_default_block_size) { + size_triple_t t(b.compact_product_size); + Index k = t.k, m = t.m, n = t.n; + internal::computeProductBlockingSizes<Scalar, Scalar>(k, m, n); + s << " default(" << k << ", " << m << ", " << n << ")"; + } else { + s << " " << hex << b.compact_block_size << 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() +{ + size_triple_t productsizes(compact_product_size); + + if (use_default_block_size) { + eigen_use_specific_block_size = false; + } else { + // feed eigen with our custom blocking params + eigen_use_specific_block_size = true; + size_triple_t blocksizes(compact_block_size); + 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(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].noalias() = 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 <typename T> +string type_name() +{ + return "unknown"; +} + +template<> +string type_name<float>() +{ + return "float"; +} + +template<> +string type_name<double>() +{ + return "double"; +} + +struct action_t +{ + virtual const char* invokation_name() const { abort(); return nullptr; } + virtual void run() const { abort(); } + virtual ~action_t() {} +}; + +void show_usage_and_exit(int /*argc*/, char* argv[], + const vector<unique_ptr<action_t>>& available_actions) +{ + cerr << "usage: " << argv[0] << " <action> [options...]" << endl << endl; + cerr << "available actions:" << endl << endl; + for (auto it = available_actions.begin(); it != available_actions.end(); ++it) { + cerr << " " << (*it)->invokation_name() << endl; + } + cerr << endl; + cerr << "options:" << 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); +} + +float measure_clock_speed() +{ + cerr << "Measuring clock speed... \r" << flush; + + vector<float> all_gflops; + for (int i = 0; i < 8; i++) { + benchmark_t b(1024, 1024, 1024); + b.run(); + all_gflops.push_back(b.gflops); + } + + sort(all_gflops.begin(), all_gflops.end()); + float stable_estimate = all_gflops[2] + all_gflops[3] + all_gflops[4] + all_gflops[5]; + + // multiply by an arbitrary constant to discourage trying doing anything with the + // returned values besides just comparing them with each other. + float result = stable_estimate * 123.456f; + + return result; +} + +struct human_duration_t +{ + int seconds; + human_duration_t(int s) : seconds(s) {} +}; + +ostream& operator<<(ostream& s, const human_duration_t& d) +{ + int remainder = d.seconds; + if (remainder > 3600) { + int hours = remainder / 3600; + s << hours << " h "; + remainder -= hours * 3600; + } + if (remainder > 60) { + int minutes = remainder / 60; + s << minutes << " min "; + remainder -= minutes * 60; + } + if (d.seconds < 600) { + s << remainder << " s"; + } + return s; +} + +const char session_filename[] = "/data/local/tmp/benchmark-blocking-sizes-session.data"; + +void serialize_benchmarks(const char* filename, const vector<benchmark_t>& benchmarks, size_t first_benchmark_to_run) +{ + FILE* file = fopen(filename, "w"); + if (!file) { + cerr << "Could not open file " << filename << " for writing." << endl; + cerr << "Do you have write permissions on the current working directory?" << endl; + exit(1); + } + size_t benchmarks_vector_size = benchmarks.size(); + fwrite(&max_clock_speed, sizeof(max_clock_speed), 1, file); + fwrite(&benchmarks_vector_size, sizeof(benchmarks_vector_size), 1, file); + fwrite(&first_benchmark_to_run, sizeof(first_benchmark_to_run), 1, file); + fwrite(benchmarks.data(), sizeof(benchmark_t), benchmarks.size(), file); + fclose(file); +} + +bool deserialize_benchmarks(const char* filename, vector<benchmark_t>& benchmarks, size_t& first_benchmark_to_run) +{ + FILE* file = fopen(filename, "r"); + if (!file) { + return false; + } + if (1 != fread(&max_clock_speed, sizeof(max_clock_speed), 1, file)) { + return false; + } + size_t benchmarks_vector_size = 0; + if (1 != fread(&benchmarks_vector_size, sizeof(benchmarks_vector_size), 1, file)) { + return false; + } + if (1 != fread(&first_benchmark_to_run, sizeof(first_benchmark_to_run), 1, file)) { + return false; + } + benchmarks.resize(benchmarks_vector_size); + if (benchmarks.size() != fread(benchmarks.data(), sizeof(benchmark_t), benchmarks.size(), file)) { + return false; + } + unlink(filename); + return true; +} + +void try_run_some_benchmarks( + vector<benchmark_t>& benchmarks, + double time_start, + size_t& first_benchmark_to_run) +{ + if (first_benchmark_to_run == benchmarks.size()) { + return; + } + + double time_last_progress_update = 0; + double time_last_clock_speed_measurement = 0; + double time_now = 0; + + size_t benchmark_index = first_benchmark_to_run; + + while (true) { + float ratio_done = float(benchmark_index) / benchmarks.size(); + time_now = timer.getRealTime(); + + // We check clock speed every minute and at the end. + if (benchmark_index == benchmarks.size() || + time_now > time_last_clock_speed_measurement + 60.0f) + { + time_last_clock_speed_measurement = time_now; + + // Ensure that clock speed is as expected + float current_clock_speed = measure_clock_speed(); + + // The tolerance needs to be smaller than the relative difference between + // clock speeds that a device could operate under. + // It seems unlikely that a device would be throttling clock speeds by + // amounts smaller than 2%. + // With a value of 1%, I was getting within noise on a Sandy Bridge. + const float clock_speed_tolerance = 0.02f; + + if (current_clock_speed > (1 + clock_speed_tolerance) * max_clock_speed) { + // Clock speed is now higher than we previously measured. + // Either our initial measurement was inaccurate, which won't happen + // too many times as we are keeping the best clock speed value and + // and allowing some tolerance; or something really weird happened, + // which invalidates all benchmark results collected so far. + // Either way, we better restart all over again now. + if (benchmark_index) { + cerr << "Restarting at " << 100.0f * ratio_done + << " % because clock speed increased. " << endl; + } + max_clock_speed = current_clock_speed; + first_benchmark_to_run = 0; + return; + } + + bool rerun_last_tests = false; + + if (current_clock_speed < (1 - clock_speed_tolerance) * max_clock_speed) { + cerr << "Measurements completed so far: " + << 100.0f * ratio_done + << " % " << endl; + cerr << "Clock speed seems to be only " + << current_clock_speed/max_clock_speed + << " times what it used to be." << endl; + + unsigned int seconds_to_sleep_if_lower_clock_speed = 1; + + while (current_clock_speed < (1 - clock_speed_tolerance) * max_clock_speed) { + if (seconds_to_sleep_if_lower_clock_speed > 32) { + cerr << "Sleeping longer probably won't make a difference." << endl; + cerr << "Serializing benchmarks to " << session_filename << endl; + serialize_benchmarks(session_filename, benchmarks, first_benchmark_to_run); + cerr << "Now restart this benchmark, and it should pick up where we left." << endl; + exit(2); + } + rerun_last_tests = true; + cerr << "Sleeping " + << seconds_to_sleep_if_lower_clock_speed + << " s... \r" << endl; + sleep(seconds_to_sleep_if_lower_clock_speed); + current_clock_speed = measure_clock_speed(); + seconds_to_sleep_if_lower_clock_speed *= 2; + } + } + + if (rerun_last_tests) { + cerr << "Redoing the last " + << 100.0f * float(benchmark_index - first_benchmark_to_run) / benchmarks.size() + << " % because clock speed had been low. " << endl; + return; + } + + // nothing wrong with the clock speed so far, so there won't be a need to rerun + // benchmarks run so far in case we later encounter a lower clock speed. + first_benchmark_to_run = benchmark_index; + } + + if (benchmark_index == benchmarks.size()) { + // We're done! + first_benchmark_to_run = benchmarks.size(); + // Erase progress info + cerr << " " << endl; + return; + } + + // Display progress info on stderr + if (time_now > time_last_progress_update + 1.0f) { + time_last_progress_update = time_now; + cerr << "Measurements... " << 100.0f * ratio_done + << " %, ETA " + << human_duration_t(float(time_now - time_start) * (1.0f - ratio_done) / ratio_done) + << " \r" << flush; + } + + // This is where we actually run a benchmark! + benchmarks[benchmark_index].run(); + benchmark_index++; + } +} + +void run_benchmarks(vector<benchmark_t>& benchmarks) +{ + size_t first_benchmark_to_run; + vector<benchmark_t> deserialized_benchmarks; + bool use_deserialized_benchmarks = false; + if (deserialize_benchmarks(session_filename, deserialized_benchmarks, first_benchmark_to_run)) { + cerr << "Found serialized session with " + << 100.0f * first_benchmark_to_run / deserialized_benchmarks.size() + << " % already done" << endl; + if (deserialized_benchmarks.size() == benchmarks.size() && + first_benchmark_to_run > 0 && + first_benchmark_to_run < benchmarks.size()) + { + use_deserialized_benchmarks = true; + } + } + + if (use_deserialized_benchmarks) { + benchmarks = deserialized_benchmarks; + } else { + // not using deserialized benchmarks, starting from scratch + first_benchmark_to_run = 0; + + // Randomly shuffling benchmarks allows us to get accurate enough progress info, + // as now the cheap/expensive benchmarks are randomly mixed so they average out. + // It also means that if data is corrupted for some time span, the odds are that + // not all repetitions of a given benchmark will be corrupted. + random_shuffle(benchmarks.begin(), benchmarks.end()); + } + + for (int i = 0; i < 4; i++) { + max_clock_speed = max(max_clock_speed, measure_clock_speed()); + } + + double time_start = 0.0; + while (first_benchmark_to_run < benchmarks.size()) { + if (first_benchmark_to_run == 0) { + time_start = timer.getRealTime(); + } + try_run_some_benchmarks(benchmarks, + time_start, + first_benchmark_to_run); + } + + // 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<benchmark_t> 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); + } + } + + // keep and return only the best benchmarks + benchmarks = best_benchmarks; +} + +struct measure_all_pot_sizes_action_t : action_t +{ + virtual const char* invokation_name() const { return "all-pot-sizes"; } + virtual void run() const + { + vector<benchmark_t> 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) { + benchmarks.emplace_back(ksize, msize, nsize, kblock, mblock, nblock); + } + } + } + } + } + } + } + + run_benchmarks(benchmarks); + + cout << "BEGIN MEASUREMENTS ALL POT SIZES" << endl; + for (auto it = benchmarks.begin(); it != benchmarks.end(); ++it) { + cout << *it << endl; + } + } +}; + +struct measure_default_sizes_action_t : action_t +{ + virtual const char* invokation_name() const { return "default-sizes"; } + virtual void run() const + { + vector<benchmark_t> 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) { + benchmarks.emplace_back(ksize, msize, nsize); + } + } + } + } + + run_benchmarks(benchmarks); + + cout << "BEGIN MEASUREMENTS DEFAULT SIZES" << endl; + for (auto it = benchmarks.begin(); it != benchmarks.end(); ++it) { + cout << *it << endl; + } + } +}; + +int main(int argc, char* argv[]) +{ + double time_start = timer.getRealTime(); + cout.precision(4); + cerr.precision(4); + + vector<unique_ptr<action_t>> available_actions; + available_actions.emplace_back(new measure_all_pot_sizes_action_t); + available_actions.emplace_back(new measure_default_sizes_action_t); + + auto action = available_actions.end(); + + if (argc <= 1) { + show_usage_and_exit(argc, argv, available_actions); + } + for (auto it = available_actions.begin(); it != available_actions.end(); ++it) { + if (!strcmp(argv[1], (*it)->invokation_name())) { + action = it; + break; + } + } + + if (action == available_actions.end()) { + show_usage_and_exit(argc, argv, available_actions); + } + + for (int i = 2; 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(argc, argv, available_actions); + } + } + + print_cpuinfo(); + + cout << "benchmark parameters:" << endl; + cout << "pointer size: " << 8*sizeof(void*) << " bits" << endl; + cout << "scalar type: " << type_name<Scalar>() << endl; + cout << "packet size: " << internal::packet_traits<MatrixType::Scalar>::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; + + (*action)->run(); + + double time_end = timer.getRealTime(); + cerr << "Finished in " << human_duration_t(time_end - time_start) << endl; +} |