Re: [boost] A fast-pathed rw-mutex algorithm for Boost...

From: Howard Hinnant (hinnant_at_[hidden])
Date: 2006-10-24 14:35:09

On Oct 24, 2006, at 12:15 PM, Peter Dimov wrote:

> There's also an implementation by Ion Gaztañaga:
>
> http://boost.cvs.sourceforge.net/boost/boost/boost/interprocess/ 
> sync/interprocess_upgradable_mutex.hpp?revision=1.4&view=markup
>
> in which he implements yet another Terekhov algorithm (AFAIK).

Imho Terekhov's algorithm is the way to go regarding reader/writer  
priority.  I've beat on this algorithm fairly heavily in my own  
implementation of it, and it really performs nicely.  Take a look at  
this test case originally inspired by Peter:

http://home.twcny.rr.com/hinnant/cpp_extensions/rw_perf.html

You can ignore the move-aspects of it, and even the upgradable aspect  
of it if you want.  But try to get the I/O part of it working on your  
system (gotoxy).  Then crank up the number of readers/writers and  
play with the protected section cost (vec_len).  Then observe the  
progress of the different kinds of threads.  In my experiments no  
thread is ever shut out, no matter how high the contention gets.   
This is a very desirable property.

-Howard