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Subject: Re: [boost] Portable robust mutex an another try...
From: Francisco José Tapia (fjtapia_at_[hidden])
Date: 2014-07-18 15:36:37


Perhaps it can be useful.

In my project ( Countertree ) I designed a new kind of mutex using only
atomic variables and the yield function. The performance is similar to the
native mutex of the compilers, and provide me flexibility for to design in
a easy way a mutex single writer multiple reader.

If you want to take a look you can see a description in

https://dl.dropboxusercontent.com/u/8437476/works/countertree_2.0/doc/single_writer_multiple_readers_mutex.pdf

and the code is in the download option of the documentation project

https://dl.dropboxusercontent.com/u/8437476/works/countertree_2.0/doc/index.html

If you need any explanation, please, ask me , and I will try to explain.

regards

*The project countertree is the implementation of red-balck trees with
access by position and parallel algorithms.
It is pending of the final review since two years ago. I need reviewers for
the project.
It can be useful to the C++ community because don't exist at today (or at
least I don't know) any other library with these capabilities.

2014-07-18 9:08 GMT+02:00 Ladislav Sopko <lsopko_at_[hidden]>:

>
> Hello,
>
> I did try to continue with */Ion Gaztanaga's /*idea of portable robust
> mutex.
> I post my code and considerations in codereview.
>
> http://codereview.stackexchange.com/questions/57083/portable-c-
> boostiterprocessmutex-an-another-try
>
>
> I hope to find some one to discuss about.
>
> thx
>
> Hi,
>>
>> The portable mutex has been in dormant state for a long time, so thanks
>> for recovering it ;-)
>>
>> It wasn't further developed and I think your proposal could be an
>> improvement, although I still don't like the preallocation of a 4MB
>> file. I have no much time lately to review and add improvements to
>> Interprocess, but please add this link or the patch to a boost trac
>> ticket or as a GitHub pull request so that this is not forgotten when I
>> find some time.
>>
>> Best,
>>
>> Ion
>>
>>
>>
>> Hi,
>
> Allocation of that 4MB is small fee for much better performance,
> because continuous
> search of files on disk slow it down really hard. Then I think to
> extend it with time stamp as
>
> Niall Douglas wrote. I just need atomic CAS for 64bit. Cause the
> time stamp and process ID
> must be changed in one shot. Then I can skip many robust checks, if
> the time from last lock
> is shorter than some predefined interval. So many regular locks will
> neither test
> file lock and it will run faster. In case one process die, there
> will be expired
> timeout and lock candidate will go check file lock.
> I'll check if I can add a 64bit CAS in
> boost\interprocess\detail\atomic.hpp. (if you know
> how it should be done, it will be a big help for me, cause I have
> not a lot of practice in atomic portable world.)
>
>
> regards
>
>
>
> --
> Sopko Ladislav
>
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