From 99fa28782f406675ea9746497695b39b50eaff80 Mon Sep 17 00:00:00 2001
From: Jean Pierre Cimalando <jp-dev@inbox.ru>
Date: Sat, 16 May 2020 16:37:28 +0200
Subject: [PATCH] Add interpolators benchmark

---
 benchmarks/BM_interpolators.cpp | 86 +++++++++++++++++++++++++++++++++
 benchmarks/CMakeLists.txt       |  2 +
 2 files changed, 88 insertions(+)
 create mode 100644 benchmarks/BM_interpolators.cpp

diff --git a/benchmarks/BM_interpolators.cpp b/benchmarks/BM_interpolators.cpp
new file mode 100644
index 00000000..5935a6de
--- /dev/null
+++ b/benchmarks/BM_interpolators.cpp
@@ -0,0 +1,86 @@
+// SPDX-License-Identifier: BSD-2-Clause
+
+// This code is part of the sfizz library and is licensed under a BSD 2-clause
+// license. You should have receive a LICENSE.md file along with the code.
+// If not, contact the sfizz maintainers at https://github.com/sfztools/sfizz
+
+#include "Interpolators.h"
+#include "ScopedFTZ.h"
+#include "absl/types/span.h"
+#include <benchmark/benchmark.h>
+#include <random>
+
+class Interpolators : public benchmark::Fixture {
+public:
+    void SetUp(const ::benchmark::State& state)
+    {
+        std::random_device rd { };
+        std::mt19937 gen { rd() };
+        std::uniform_real_distribution<float> dist { -1.0f, 1.0f };
+
+        const size_t numFramesIn = state.range(0);
+        inputBuffer = std::vector<float>(numFramesIn + excessFrames);
+
+        // any ratio will do, compute time will be proportional
+        static constexpr float ratio = 1.234;
+
+        const size_t numFramesOut = static_cast<size_t>(std::ceil(numFramesIn * ratio));
+        input = absl::MakeSpan(inputBuffer.data(), numFramesIn);
+        output = std::vector<float>(numFramesOut);
+        std::generate(input.begin(), input.end(), [&]() { return dist(gen); });
+    }
+
+    void TearDown(const ::benchmark::State& /* state */)
+    {
+    }
+
+    std::vector<float> inputBuffer;
+    absl::Span<float> input;
+    std::vector<float> output;
+
+    enum { excessFrames = 8 };
+};
+
+template <sfz::InterpolatorModel M>
+static void doInterpolation(absl::Span<const float> input, absl::Span<float> output)
+{
+    const float kOutToIn = static_cast<float>(input.size()) / output.size();
+
+    for (size_t iOut = 0; iOut < output.size(); ++iOut) {
+        float posIn = iOut * kOutToIn;
+        unsigned dec = static_cast<int>(posIn);
+        float frac = posIn - dec;
+        output[iOut] = sfz::interpolate<M>(&input[dec], frac);
+    }
+}
+
+BENCHMARK_DEFINE_F(Interpolators, Linear)(benchmark::State& state)
+{
+    ScopedFTZ ftz;
+
+    for (auto _ : state) {
+        doInterpolation<sfz::kInterpolatorLinear>(input, absl::MakeSpan(output));
+    }
+}
+
+BENCHMARK_DEFINE_F(Interpolators, Hermite3)(benchmark::State& state)
+{
+    ScopedFTZ ftz;
+
+    for (auto _ : state) {
+        doInterpolation<sfz::kInterpolatorHermite3>(input, absl::MakeSpan(output));
+    }
+}
+
+BENCHMARK_DEFINE_F(Interpolators, Bspline3)(benchmark::State& state)
+{
+    ScopedFTZ ftz;
+
+    for (auto _ : state) {
+        doInterpolation<sfz::kInterpolatorBspline3>(input, absl::MakeSpan(output));
+    }
+}
+
+BENCHMARK_REGISTER_F(Interpolators, Linear)->RangeMultiplier(4)->Range(1 << 2, 1 << 12);
+BENCHMARK_REGISTER_F(Interpolators, Hermite3)->RangeMultiplier(4)->Range(1 << 2, 1 << 12);
+BENCHMARK_REGISTER_F(Interpolators, Bspline3)->RangeMultiplier(4)->Range(1 << 2, 1 << 12);
diff --git a/benchmarks/CMakeLists.txt b/benchmarks/CMakeLists.txt
index 96595e47..1b2fcdbe 100644
--- a/benchmarks/CMakeLists.txt
+++ b/benchmarks/CMakeLists.txt
@@ -89,6 +89,8 @@ target_link_libraries(bm_readChunkFlac PRIVATE sfizz-sndfile)
 sfizz_add_benchmark(bm_resampleChunk BM_resampleChunk.cpp)
 target_link_libraries(bm_resampleChunk PRIVATE sfizz-sndfile)
 
+sfizz_add_benchmark(bm_interpolators BM_interpolators.cpp)
+
 sfizz_add_benchmark(bm_filterModulation BM_filterModulation.cpp ../src/sfizz/SfzFilter.cpp)
 target_link_libraries(bm_filterModulation PRIVATE sfizz-sndfile)