Re: [boost] [lock-free] CDS -yet another lock-free library

Subject: Re: [boost] [lock-free] CDS -yet another lock-free library
From: Daniel Trebbien (dtrebbien_at_[hidden])
Date: 2010-03-28 18:02:02

>> I'd like to present to boost community the CDS (Concurrent Data
>> Structure) C++ library at libcds.sourceforge.net. It is an
>> attempt to generalize well-known lock-free (and a few lock-based)
>> data structures discovered by famous researches (M.Michael,
>> N.Shavit and others). The library is mostly header-based, only
>> the kernel of light-weight memory managers is resided in small
>> dynamic library.
>> The CDS library supports a set of modern processor architectures:
>> x86, amd64, ia64, sparc; compiler supported is GCC 4 and MS Visual
>> C++ 2008.  The last CDS release 0.6.0 is developed close to C++
>> Memory Model proposal.
>> I need the recommendations from boost community about :
>> 1. Are the atomic primitives implemented correct for each of supported
>> processor?.. I'm not an expert in this area...
>
> Have you considered using the proposed Boost.Atomic?  This should
> support more platforms.
>
> If there is something missing from Boost.Atomic that is needed for this
> purpose, it would be useful to know about it.

Hi Phil,

I searched the sandbox to see if there was a folder for Boost.Atomic, just to make sure that I didn't miss it. Are you referring to the contents of <boost/interprocess/detail/atomic.hpp>?

A while ago I was working on a project that required some new atomic primitives which were missing from that file, and I think that they would be nice additions to an atomic operations library:

1. `atomic_dec_if_nz` - Atomically decrements an integer if it is not zero
2. `atomic_inc_if_nmax` - Atomically increments an integer if it is not the maximum possible value for its type
3. `atomic_inc_if_nz_nmax` - Atomically increments an integer if it is neither zero or the maximum possible value for its type

I have attached a file that contains my (g++, x86) implementations of these functions for `uint8_t` and a basic unit test. Do you think that these would be good to include in Boost.Atomic? If so I can work on x86 versions for more standard int types as well as different compilers.

Daniel