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nlohmann · Jul 4, 2018 · 9c773ef · 9c773ef
1 parent 9007790
commit 9c773ef
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Showing 4 changed files with 108 additions and 84 deletions.
diff --git a/benchmarks/CMakeLists.txt b/benchmarks/CMakeLists.txt
@@ -1,8 +1,6 @@
 cmake_minimum_required(VERSION 3.8)
 project(JSON_Benchmarks LANGUAGES CXX)
 
-# set compiler flags
-   set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fno-devirtualize")
 
 # configure Google Benchmarks
 set(BENCHMARK_ENABLE_TESTING OFF CACHE INTERNAL "" FORCE)
@@ -20,6 +18,6 @@ file(COPY ${CMAKE_SOURCE_DIR}/../test/data/regression/floats.json
     DESTINATION data/numbers)
 
 # benchmark binary
-add_executable(json_benchmarks src/benchmarks.cpp)
+add_executable(json_benchmarks src/benchmarks.cpp src/virtual.cpp)
 target_compile_features(json_benchmarks PRIVATE cxx_std_11)
 target_link_libraries(json_benchmarks benchmark ${CMAKE_THREAD_LIBS_INIT})
diff --git a/benchmarks/src/benchmarks.cpp b/benchmarks/src/benchmarks.cpp
@@ -1,83 +1,12 @@
 #include "benchmark/benchmark.h"
 #include <nlohmann/json.hpp>
 #include <fstream>
+#include "virtual.h"
 
 using json = nlohmann::json;
 
 namespace
 {
-struct abstract_bench_sax
-{
-    virtual bool null() = 0;
-    virtual bool boolean(bool) = 0;
-    virtual bool number_integer(json::number_integer_t) = 0;
-    virtual bool number_unsigned(json::number_unsigned_t) = 0;
-    virtual bool number_float(json::number_float_t, const json::string_t&) = 0;
-    virtual bool string(json::string_t& val) = 0;
-    virtual bool start_object(std::size_t elements) = 0;
-    virtual bool key(json::string_t& val) = 0;
-    virtual bool end_object() = 0;
-    virtual bool start_array(std::size_t elements) = 0;
-    virtual bool end_array() = 0;
-    // FIXME exceptions should not be in detail
-    virtual bool parse_error(std::size_t position, const std::string& last_token,
-                             const nlohmann::detail::exception& ex) = 0;
-};
-
-struct virtual_bench_sax : public abstract_bench_sax
-{
-    bool null() override
-    {
-        return true;
-    }
-    bool boolean(bool) override
-    {
-        return true;
-    }
-    bool number_integer(json::number_integer_t) override
-    {
-        return true;
-    }
-    bool number_unsigned(json::number_unsigned_t) override
-    {
-        return true;
-    }
-    bool number_float(json::number_float_t, const json::string_t&) override
-    {
-        return true;
-    }
-    bool string(json::string_t& val) override
-    {
-        return true;
-    }
-    bool start_object(std::size_t elements) override
-    {
-        return true;
-    }
-    bool key(json::string_t& val) override
-    {
-        return true;
-    }
-    bool end_object() override
-    {
-        return true;
-    }
-    bool start_array(std::size_t elements) override
-    {
-        return true;
-    }
-    bool end_array() override
-    {
-        return true;
-    }
-    // FIXME exceptions should not be in detail
-    bool parse_error(std::size_t position, const std::string& last_token,
-                     const nlohmann::detail::exception& ex) override
-    {
-        return true;
-    }
-};
-
 struct template_sax
 {
     bool null()
@@ -137,15 +66,14 @@ struct template_sax
 // parse JSON from file (SAX)
 //////////////////////////////////////////////////////////////////////////////
 
-template <typename SAX, typename SAXBase = SAX>
-static void ParseFileSAX(benchmark::State& state, const char* filename)
+static void ParseFileSAXVirtual(benchmark::State& state, const char* filename)
 {
     while (state.KeepRunning())
     {
         state.PauseTiming();
         auto* f = new std::ifstream(filename);
         auto* j = new json();
-        SAXBase* sax = new SAX;
+        auto sax = create_virtual_sax();
         state.ResumeTiming();
 
         *j = json::sax_parse(*f, sax);
@@ -161,14 +89,27 @@ static void ParseFileSAX(benchmark::State& state, const char* filename)
     state.SetBytesProcessed(state.iterations() * file.tellg());
 }
 
-static void ParseFileSAXVirtual(benchmark::State& state, const char* filename)
-{
-    ParseFileSAX<virtual_bench_sax, abstract_bench_sax>(state, filename);
-}
-
 static void ParseFileSAXTemplate(benchmark::State& state, const char* filename)
 {
-    ParseFileSAX<template_sax>(state, filename);
+    while (state.KeepRunning())
+    {
+        state.PauseTiming();
+        auto* f = new std::ifstream(filename);
+        auto* j = new json();
+        auto sax = new template_sax;
+        state.ResumeTiming();
+
+        *j = json::sax_parse(*f, sax);
+
+        state.PauseTiming();
+        delete f;
+        delete j;
+        delete sax;
+        state.ResumeTiming();
+    }
+
+    std::ifstream file(filename, std::ios::binary | std::ios::ate);
+    state.SetBytesProcessed(state.iterations() * file.tellg());
 }
 
 BENCHMARK_CAPTURE(ParseFileSAXVirtual, jeopardy,      "data/jeopardy/jeopardy.json")->Unit(benchmark::kMillisecond);

diff --git a/benchmarks/src/virtual.cpp b/benchmarks/src/virtual.cpp
@@ -0,0 +1,62 @@
+#include "virtual.h"
+
+using json = nlohmann::json;
+
+struct virtual_bench_sax : public abstract_bench_sax
+{
+    bool null() override
+    {
+        return true;
+    }
+    bool boolean(bool) override
+    {
+        return true;
+    }
+    bool number_integer(json::number_integer_t) override
+    {
+        return true;
+    }
+    bool number_unsigned(json::number_unsigned_t) override
+    {
+        return true;
+    }
+    bool number_float(json::number_float_t, const json::string_t&) override
+    {
+        return true;
+    }
+    bool string(json::string_t& val) override
+    {
+        return true;
+    }
+    bool start_object(std::size_t elements) override
+    {
+        return true;
+    }
+    bool key(json::string_t& val) override
+    {
+        return true;
+    }
+    bool end_object() override
+    {
+        return true;
+    }
+    bool start_array(std::size_t elements) override
+    {
+        return true;
+    }
+    bool end_array() override
+    {
+        return true;
+    }
+    // FIXME exceptions should not be in detail
+    bool parse_error(std::size_t position, const std::string& last_token,
+                     const nlohmann::detail::exception& ex) override
+    {
+        return true;
+    }
+};
+
+abstract_bench_sax* create_virtual_sax()
+{
+  return new virtual_bench_sax;
+}
diff --git a/benchmarks/src/virtual.h b/benchmarks/src/virtual.h
@@ -0,0 +1,23 @@
+#pragma once
+
+#include <nlohmann/json.hpp>
+
+struct abstract_bench_sax
+{
+    virtual bool null() = 0;
+    virtual bool boolean(bool) = 0;
+    virtual bool number_integer(nlohmann::json::number_integer_t) = 0;
+    virtual bool number_unsigned(nlohmann::json::number_unsigned_t) = 0;
+    virtual bool number_float(nlohmann::json::number_float_t, const nlohmann::json::string_t&) = 0;
+    virtual bool string(nlohmann::json::string_t& val) = 0;
+    virtual bool start_object(std::size_t elements) = 0;
+    virtual bool key(nlohmann::json::string_t& val) = 0;
+    virtual bool end_object() = 0;
+    virtual bool start_array(std::size_t elements) = 0;
+    virtual bool end_array() = 0;
+    // FIXME exceptions should not be in detail
+    virtual bool parse_error(std::size_t position, const std::string& last_token,
+                             const nlohmann::detail::exception& ex) = 0;
+};
+
+abstract_bench_sax* create_virtual_sax();