[Boost-bugs] [Boost C++ Libraries] #3500: Optimization for win32 mutex implementation

Subject: [Boost-bugs] [Boost C++ Libraries] #3500: Optimization for win32 mutex implementation
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2009-10-01 13:50:40

#3500: Optimization for win32 mutex implementation
--------------------------+-------------------------------------------------
 Reporter:  andysem       |       Owner:  anthonyw    
     Type:  Patches       |      Status:  new         
Milestone:  Boost 1.41.0  |   Component:  thread      
  Version:  Boost 1.40.0  |    Severity:  Optimization
 Keywords:  thread mutex  |  
--------------------------+-------------------------------------------------
 While I was porting my code from raw Win32 CRITICAL_SECTION to
 boost::mutex I noticed a performance drop of around 10% in cases where
 thread contention was quite rare.

 After some experimenting it appeared that the problem was in the
 boost/thread/win32/basic_timed_mutex.hpp file. The basic_timed_mutex::lock
 method always constructed time point to pass it to the timed_lock method,
 even though it is not needed for the quick path. When I modified the
 methods the performance counters met values I had with raw
 CRITICAL_SECTION.

 Please, find the patch attached. The patch is against 1.40 release.

 PS: I'm using MSVC 7.1, I didn't test on newer compilers.

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Ticket URL: <https://svn.boost.org/trac/boost/ticket/3500>
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