Medusa Slockbower
a35f2a699d
- Lots of bug-fixing for containers - Performance optimization for containers
68 lines
2.0 KiB
C++
68 lines
2.0 KiB
C++
// =====================================================================================================================
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// I release this example code into the public domain
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// =====================================================================================================================
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// This file contains code that tests the efficiency of the assert macro scheme in
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// fennec engine. This is purely looking at the branching aspect and not the private
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// assert definition. The code only uses passing values to see any performance overhead
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// from the conditional
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// This code is based on the example code that cppreference provides at
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// https://en.cppreference.com/w/cpp/language/attributes/likely
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// To my surprise, the difference between them is negligible.
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// Even when n is a crazy number like one billion, there isn't a conclusive difference.
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// I checked that it isn't the lambdas, they are optimized out.
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// In debug mode, the results are to be expected; release < experimental < control
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#include <cassert>
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#include <chrono>
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#include <cstddef>
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#include <iomanip>
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#include <iostream>
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#define assert_c(expression) \
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if(not(expression)) { \
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std::abort(); \
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}
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#define assert_e(expression) \
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if(not(expression)) [[unlikely]] { \
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std::abort(); \
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}
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#define assert_r(expression) (static_cast<void> (0))
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volatile int sink{}; // ensures a side effect
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int main() {
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auto benchmark = [](auto fun, auto rem) {
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srand(0);
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const auto start = std::chrono::high_resolution_clock::now();
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for (auto size{1ULL}; size != 10'000'000ULL; ++size)
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sink = fun(rand());
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const std::chrono::duration<double> diff =
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std::chrono::high_resolution_clock::now() - start;
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std::cout << "Time: " << std::fixed << std::setprecision(6) << diff.count()
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<< " sec " << rem << std::endl;
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};
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benchmark([](int x) {
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assert_c(0 <= x && x <= RAND_MAX);
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return x;
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}, "control");
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benchmark([](int x) {
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assert_r(0 <= x && x <= RAND_MAX);
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return x;
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}, "release");
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benchmark([](int x) {
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assert_e(0 <= x && x <= RAND_MAX);
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return x;
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}, "experimental");
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}
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