151 lines
4.4 KiB
C++
151 lines
4.4 KiB
C++
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// Copyright Oliver Kowalke 2009.
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// Distributed under the Boost Software License, Version 1.0.
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// (See accompanying file LICENSE_1_0.txt or copy at
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// http://www.boost.org/LICENSE_1_0.txt)
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#include <cstddef>
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#include <cstdlib>
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#include <iostream>
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#include <stdexcept>
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#include <boost/context/detail/fcontext.hpp>
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#include <boost/cstdint.hpp>
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#include <boost/program_options.hpp>
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#include "../clock.hpp"
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#include "../cycle.hpp"
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template< std::size_t Max, std::size_t Default, std::size_t Min >
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class simple_stack_allocator
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{
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public:
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static std::size_t maximum_stacksize()
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{ return Max; }
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static std::size_t default_stacksize()
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{ return Default; }
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static std::size_t minimum_stacksize()
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{ return Min; }
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void * allocate( std::size_t size) const
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{
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BOOST_ASSERT( minimum_stacksize() <= size);
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BOOST_ASSERT( maximum_stacksize() >= size);
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void * limit = std::malloc( size);
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if ( ! limit) throw std::bad_alloc();
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return static_cast< char * >( limit) + size;
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}
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void deallocate( void * vp, std::size_t size) const
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{
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BOOST_ASSERT( vp);
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BOOST_ASSERT( minimum_stacksize() <= size);
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BOOST_ASSERT( maximum_stacksize() >= size);
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void * limit = static_cast< char * >( vp) - size;
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std::free( limit);
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}
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};
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typedef simple_stack_allocator<
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8 * 1024 * 1024, 64 * 1024, 8 * 1024
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> stack_allocator;
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boost::uint64_t jobs = 1000000;
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static void foo( boost::context::detail::transfer_t t_) {
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boost::context::detail::transfer_t t = t_;
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while ( true) {
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t = boost::context::detail::jump_fcontext( t.fctx, 0);
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}
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}
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duration_type measure_time_fc() {
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stack_allocator stack_alloc;
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boost::context::detail::fcontext_t ctx = boost::context::detail::make_fcontext(
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stack_alloc.allocate( stack_allocator::default_stacksize() ),
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stack_allocator::default_stacksize(),
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foo);
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// cache warum-up
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boost::context::detail::transfer_t t = boost::context::detail::jump_fcontext( ctx, 0);
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time_point_type start( clock_type::now() );
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for ( std::size_t i = 0; i < jobs; ++i) {
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t = boost::context::detail::jump_fcontext( t.fctx, 0);
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}
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duration_type total = clock_type::now() - start;
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total -= overhead_clock(); // overhead of measurement
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total /= jobs; // loops
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total /= 2; // 2x jump_fcontext
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return total;
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}
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#ifdef BOOST_CONTEXT_CYCLE
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cycle_type measure_cycles_fc() {
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stack_allocator stack_alloc;
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boost::context::detail::fcontext_t ctx = boost::context::detail::make_fcontext(
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stack_alloc.allocate( stack_allocator::default_stacksize() ),
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stack_allocator::default_stacksize(),
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foo);
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// cache warum-up
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boost::context::detail::transfer_t t = boost::context::detail::jump_fcontext( ctx, 0);
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cycle_type start( cycles() );
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for ( std::size_t i = 0; i < jobs; ++i) {
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t = boost::context::detail::jump_fcontext( t.fctx, 0);
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}
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cycle_type total = cycles() - start;
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total -= overhead_cycle(); // overhead of measurement
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total /= jobs; // loops
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total /= 2; // 2x jump_fcontext
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return total;
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}
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#endif
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int main( int argc, char * argv[])
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{
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try
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{
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boost::program_options::options_description desc("allowed options");
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desc.add_options()
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("help", "help message")
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("jobs,j", boost::program_options::value< boost::uint64_t >( & jobs), "jobs to run");
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boost::program_options::variables_map vm;
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boost::program_options::store(
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boost::program_options::parse_command_line(
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argc,
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argv,
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desc),
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vm);
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boost::program_options::notify( vm);
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if ( vm.count("help") ) {
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std::cout << desc << std::endl;
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return EXIT_SUCCESS;
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}
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boost::uint64_t res = measure_time_fc().count();
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std::cout << "fcontext_t: average of " << res << " nano seconds" << std::endl;
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#ifdef BOOST_CONTEXT_CYCLE
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res = measure_cycles_fc();
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std::cout << "fcontext_t: average of " << res << " cpu cycles" << std::endl;
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#endif
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return EXIT_SUCCESS;
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}
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catch ( std::exception const& e)
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{ std::cerr << "exception: " << e.what() << std::endl; }
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catch (...)
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{ std::cerr << "unhandled exception" << std::endl; }
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return EXIT_FAILURE;
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}
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