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From: Michael Dickey (mike_at_[hidden])
Date: 2008-04-17 19:47:03

Yes, I'm using a multi-core machine. Where in my code would I need
to add barriers, or is this perhaps a limitation in APR's CAS?


On Apr 17, 2008, at 3:45 PM, Patrick Twohig wrote:
> Are you running it on a multicore machine or single core? That
> radically
> changes things. I was having the same problem. To test I ran 500
> threads
> or so a third of them were producers. My suspicion was that I wasn't
> enforcing the proper memory barriers because for x86 I had to write
> my own
> CAS in assembly.
> On Thu, Apr 17, 2008 at 3:23 PM, Michael Dickey
> <mike_at_[hidden]> wrote:
>> I wrote a C++ lock free queue implementation recently based on the
>> Michael & Scott algorithm, that uses APR's atomics. It's available
>> at:
>> You're welcome to use it but you should be aware that it's not quite
>> debugged yet. It has issues when I tried using more than 1 producer
>> and 1 consumer thread. I wasn't sure if this was a mistake I made in
>> the code, or a limitation of the algorithm, but I assume it's the
>> former. Anyway, in the end I decided not to use the code for what I
>> was working on... But if you can find and fix the bug, it's all
>> yours! =)
>> Of course, it depends on APR's atomics.. Boost does not have any
>> compare-and-swap abstraction as I far as I know, which seems to be a
>> basic requirement for any lock-free programming. Or maybe it does
>> and
>> I just don't know?
>> Take care,
>> -Mike
>> On Apr 17, 2008, at 12:57 PM, Cory Nelson wrote:
>>> On Wed, Apr 16, 2008 at 9:58 PM, Patrick Twohig <p-twohig_at_[hidden]>
>>> wrote:
>>>> I've been looking through the docs and I was wondering if boost has
>>>> any
>>>> lock-free threadsafe containers. I know it's been brought up on
>>>> the list
>>>> before, but I was curious if anybody had a working implementation.
>>>> If
>>>> somebody is working on them, I'd like to lend a hand if possible.
>>> I have some lock-free stack/queue code for x86/x64/ia64 in c++. It
>>> only works with vc++ 2008 intrinsics right now, and the x64
>>> version is
>>> dependant on the windows memory manager if used on older CPUs. If
>>> people are interested in boostifying and porting it, I suppose we
>>> could do that.
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