[boost] sp_atomic_mt2_test: a test for mutex/shared_mutex/atomic access performance

From: Peter Dimov (pdimov_at_[hidden])
Date: 2008-05-03 19:10:19

I've added sp_atomic_mt2_test.cpp:

http://svn.boost.org/trac/boost/browser/trunk/libs/smart_ptr/test/sp_atomic_mt2_test.cpp

to the SVN; this is a reader/writer performance test that can be used to 
compare the performance of a detail::lightweight_mutex, boost::shared_mutex 
and the new atomic access operations for shared_ptr. It accepts command line 
options that can be used to achieve a variety of scenarios.

I'm currently seeing a plain mutex (maps to a CRITICAL_SECTION) 
outperforming shared_mutex for the default configuration of read/write ratio 
100:1, vector size (operation cost) 10000, no matter how many threads I use 
on a dual CPU box on Windows. This seems somewhat suspicious and may 
indicate a bug in the test. Any comments are welcome. :-)