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- // Copyright (c) 2008 Peter Dimov
- //
- // Distributed under the Boost Software License, Version 1.0.
- // See accompanying file LICENSE_1_0.txt or copy at
- // http://www.boost.org/LICENSE_1_0.txt
- #include <boost/config.hpp>
- #include <boost/shared_ptr.hpp>
- #include <boost/bind.hpp>
- #include <boost/thread/shared_mutex.hpp>
- #include <boost/thread/locks.hpp>
- #include <boost/detail/lightweight_mutex.hpp>
- #include <boost/detail/lightweight_thread.hpp>
- #include <vector>
- #include <numeric>
- #include <cstdio>
- #include <cstdlib>
- #include <cstddef>
- #include <ctime>
- //
- static void next_value( unsigned & v )
- {
- v = v % 2? 3 * v + 1: v / 2;
- }
- struct X
- {
- std::vector<unsigned> v_;
- explicit X( std::size_t n ): v_( n )
- {
- for( std::size_t i = 0; i < n; ++i )
- {
- v_[ i ] = i;
- }
- }
- unsigned get() const
- {
- return std::accumulate( v_.begin(), v_.end(), 0 );
- }
- void set()
- {
- std::for_each( v_.begin(), v_.end(), next_value );
- }
- };
- static boost::shared_ptr<X> ps;
- static boost::detail::lightweight_mutex lm;
- static boost::shared_mutex rw;
- enum prim_type
- {
- pt_mutex,
- pt_rwlock,
- pt_atomics
- };
- int read_access( prim_type pt )
- {
- switch( pt )
- {
- case pt_mutex:
- {
- boost::detail::lightweight_mutex::scoped_lock lock( lm );
- return ps->get();
- }
- case pt_rwlock:
- {
- boost::shared_lock<boost::shared_mutex> lock( rw );
- return ps->get();
- }
- case pt_atomics:
- {
- boost::shared_ptr<X> p2 = boost::atomic_load( &ps );
- return p2->get();
- }
- }
- }
- void write_access( prim_type pt )
- {
- switch( pt )
- {
- case pt_mutex:
- {
- boost::detail::lightweight_mutex::scoped_lock lock( lm );
- ps->set();
- }
- break;
- case pt_rwlock:
- {
- boost::unique_lock<boost::shared_mutex> lock( rw );
- ps->set();
- }
- break;
- case pt_atomics:
- {
- boost::shared_ptr<X> p1 = boost::atomic_load( &ps );
- for( ;; )
- {
- boost::shared_ptr<X> p2( new X( *p1 ) );
- p2->set();
- if( boost::atomic_compare_exchange( &ps, &p1, p2 ) ) break;
- }
- }
- break;
- }
- }
- void worker( int k, prim_type pt, int n, int r )
- {
- ++r;
- unsigned s = 0, nr = 0, nw = 0;
- for( int i = 0; i < n; ++i )
- {
- if( i % r )
- {
- s += read_access( pt );
- ++nr;
- }
- else
- {
- write_access( pt );
- ++s;
- ++nw;
- }
- }
- printf( "Worker %2d: %u:%u, %10u\n", k, nr, nw, s );
- }
- #if defined( BOOST_HAS_PTHREADS )
- char const * thmodel = "POSIX";
- #else
- char const * thmodel = "Windows";
- #endif
- char const * pt_to_string( prim_type pt )
- {
- switch( pt )
- {
- case pt_mutex:
- return "mutex";
- case pt_rwlock:
- return "rwlock";
- case pt_atomics:
- return "atomics";
- }
- }
- static void handle_pt_option( std::string const & opt, prim_type & pt, prim_type pt2 )
- {
- if( opt == pt_to_string( pt2 ) )
- {
- pt = pt2;
- }
- }
- static void handle_int_option( std::string const & opt, std::string const & prefix, int & k, int kmin, int kmax )
- {
- if( opt.substr( 0, prefix.size() ) == prefix )
- {
- int v = atoi( opt.substr( prefix.size() ).c_str() );
- if( v >= kmin && v <= kmax )
- {
- k = v;
- }
- }
- }
- int main( int ac, char const * av[] )
- {
- using namespace std; // printf, clock_t, clock
- int m = 4; // threads
- int n = 10000; // vector size
- int k = 1000000; // iterations
- int r = 100; // read/write ratio, r:1
- prim_type pt = pt_atomics;
- for( int i = 1; i < ac; ++i )
- {
- handle_pt_option( av[i], pt, pt_mutex );
- handle_pt_option( av[i], pt, pt_rwlock );
- handle_pt_option( av[i], pt, pt_atomics );
- handle_int_option( av[i], "n=", n, 1, INT_MAX );
- handle_int_option( av[i], "size=", n, 1, INT_MAX );
- handle_int_option( av[i], "k=", k, 1, INT_MAX );
- handle_int_option( av[i], "iterations=", k, 1, INT_MAX );
- handle_int_option( av[i], "m=", m, 1, INT_MAX );
- handle_int_option( av[i], "threads=", m, 1, INT_MAX );
- handle_int_option( av[i], "r=", r, 1, INT_MAX );
- handle_int_option( av[i], "ratio=", r, 1, INT_MAX );
- }
- printf( "%s: threads=%d size=%d iterations=%d ratio=%d %s\n\n", thmodel, m, n, k, r, pt_to_string( pt ) );
- ps.reset( new X( n ) );
- clock_t t = clock();
- std::vector<boost::detail::lw_thread_t> a( m );
- for( int i = 0; i < m; ++i )
- {
- boost::detail::lw_thread_create( a[ i ], boost::bind( worker, i, pt, k, r ) );
- }
- for( int j = 0; j < m; ++j )
- {
- boost::detail::lw_thread_join( a[ j ] );
- }
- t = clock() - t;
- double ts = static_cast<double>( t ) / CLOCKS_PER_SEC;
- printf( "%.3f seconds, %.3f accesses per microsecond.\n", ts, m * k / ts / 1e+6 );
- }
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