4b3
Subj : Re: YALFAm (Yet Another Lock Free Approach, maybe)
To   : comp.programming.threads
From : Joe Seigh
Date : Mon May 16 2005 10:22 am

On Sun, 15 May 2005 04:04:19 -0700, Chris Thomasson <_no_damn_spam_cristom@_no_damn_comcast.net_spam> wrote:

>> I have an idea about a 'mainly' lock free implementation that I'd
>> appreciate comments on.
>> I'm attempting to solve the same sort of problem as Joe Seigh's atomic_ptr
>> (http://atomic-ptr-plus.sourceforge.net/), but in a way that will work on
>> win64 and win32 (so I want to avoid assembly and reliance on instructions
>> that are not present on some processors).
>
> You can create a single-word atomic reference counted pointer with SMR that
> can outperform ( totally ia-32 specific ) atomic_ptr on x86; 'lock
> cmpxchg8b' can be expensive. SMR based reference counting doesn't have to
> rely on the hefty lock prefix on x86, it can use the "more" lightweight
> mfence instruction...
>
Instructions.  You need an additional membar for the release semantics if you
are storing into a non null hazard pointer.


-- 
Joe Seigh

When you get lemons, you make lemonade.
When you get hardware, you make software.

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