Chris Thomasson wrote:
How does the original algorithm compare to yours?
I haven't tried it yet. Will do.
Also, how many reader/writer threads are you using, and how many writes do you perform on average, 'per-writer-thread', lets say every 3 or 4 seconds?
Various. Here's the test: #include <boost/thread/thread.hpp> #include <boost/bind.hpp> #include <vector> #include <iostream> #include <ctime> int const N = 1048576; int const n = 1000; // vector size rw_mutex mtx; std::vector<int> v( n ); boost::mutex cmx; // void reader( int r ) { for( int i = 0; i < N; ++i ) { rw_mutex::scoped_read_lock lock( mtx ); int m = v.front(); for( std::vector<int>::const_iterator i = v.begin(), end = v.end(); i != end; ++i ) { assert( *i == m ); } } boost::mutex::scoped_lock lock( cmx ); std::cout << " R" << r; } void writer( int w ) { for( int i = 0; i < N; ++i ) { rw_mutex::scoped_write_lock lock( mtx ); int m = v.front(); for( std::vector<int>::iterator i = v.begin(), end = v.end(); i != end; ++i ) { ++*i; assert( *i == m + 1 ); } } boost::mutex::scoped_lock lock( cmx ); std::cout << " W" << w; } void test( int nr, int nw ) { try { std::cout << nr << "R + " << nw << "W:"; std::time_t tm = std::time( 0 ); boost::thread_group group; int i = 0; for( ; i < nr && i < nw; ++i ) { group.create_thread( boost::bind( writer, i ) ); group.create_thread( boost::bind( reader, i ) ); } for( ; i < nr; ++i ) { group.create_thread( boost::bind( reader, i ) ); } for( ; i < nw; ++i ) { group.create_thread( boost::bind( writer, i ) ); } group.join_all(); std::cout << ": " << std::time( 0 ) - tm << std::endl; } catch( std::exception const & x ) { std::cout << x.what() << std::endl; } } int main() { test( 0, 1 ); test( 0, 4 ); test( 1, 0 ); test( 1, 1 ); test( 1, 4 ); test( 2, 0 ); test( 2, 1 ); test( 2, 4 ); test( 4, 0 ); test( 4, 1 ); test( 4, 4 ); test( 16, 0 ); test( 16, 1 ); test( 16, 4 ); test( 64, 0 ); test( 64, 1 ); test( 64, 4 ); }