internal/ceres/parallel_for_benchmark.cc

// Ceres Solver - A fast non-linear least squares minimizer
// Copyright 2023 Google Inc. All rights reserved.
// http://ceres-solver.org/
//
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#include "absl/log/check.h"
#include "benchmark/benchmark.h"
#include "ceres/context_impl.h"
#include "ceres/internal/eigen.h"
#include "ceres/parallel_for.h"

namespace ceres::internal {

// Parallel for with very small amount of work per iteration and small amount of
// iterations benchmarks performance of task scheduling
static void SchedulerBenchmark(benchmark::State& state) {
  const int vector_size = static_cast<int>(state.range(0));
  const int num_threads = static_cast<int>(state.range(1));
  ContextImpl context;
  context.EnsureMinimumThreads(num_threads);

  Vector x = Vector::Random(vector_size);
  for (auto _ : state) {
    ParallelFor(
        &context, 0, vector_size, num_threads, [&x](int id) { x[id] = 0.; });
  }
  CHECK_EQ(x.squaredNorm(), 0.);
}
BENCHMARK(SchedulerBenchmark)
    ->Args({128, 1})
    ->Args({128, 2})
    ->Args({128, 4})
    ->Args({128, 8})
    ->Args({128, 16})
    ->Args({256, 1})
    ->Args({256, 2})
    ->Args({256, 4})
    ->Args({256, 8})
    ->Args({256, 16})
    ->Args({1024, 1})
    ->Args({1024, 2})
    ->Args({1024, 4})
    ->Args({1024, 8})
    ->Args({1024, 16})
    ->Args({4096, 1})
    ->Args({4096, 2})
    ->Args({4096, 4})
    ->Args({4096, 8})
    ->Args({4096, 16});

}  // namespace ceres::internal

BENCHMARK_MAIN();