[pypy-dev] Easy way to get access to cmpxchg?

[Timothy Baldridge]

Actually I just found this article:
http://stackoverflow.com/questions/12166268/wheres-the-gil-in-pypy and it
seems that the GIL is a feature specific to each interpreter. The link on
that code lead me to module/thread/gil.py and that looks like it contains
most of what I need.

Thanks!

Timothy


On Mon, Feb 24, 2014 at 1:41 PM, Timothy Baldridge <tbaldridge at gmail.com>wrote:

> What's the best way to tell rpython not to release the GIL during a given
> block of code? I haven't been able to find any code that describes when the
> GIL is acquired or when control could switch over to another thread. I'd
> prefer to have my interpreter bytecodes be atomic from the point of view
> from the program. If I had that, then I could easily build a psudo
> compare_and_swap by doing this:
>
> dont_release_gil()
> if foo.bar == oldval:
>   foo.bar = newval
> enable_gil_releasing()
>
> Thanks,
>
> Timothy
>
>
>
>
> On Sat, Feb 22, 2014 at 12:13 AM, Armin Rigo <arigo at tunes.org> wrote:
>
>> Hi Timothy,
>>
>> On 22 February 2014 01:39, Timothy Baldridge <tbaldridge at gmail.com>
>> wrote:
>> > compare_and_swap(foo.bar, oldval, newval)
>>
>> At some point we added a way to do it (basically you can do it
>> yourself, by writing a one-line function in C and calling it).  We no
>> longer do that: it's too much of a mess if you start having
>> non-GIL-protected code written in RPython.  Either you are extremely,
>> extremely careful, or random things will explode.  What we do instead,
>> e.g. in the stm branches, is to write more C code.  For the complete
>> parts that really need to run without any GIL protection, C is better
>> than RPython after all.
>>
>>
>> A bientôt,
>>
>> Armin.
>>
>
>
>
> --
> "One of the main causes of the fall of the Roman Empire was that-lacking
> zero-they had no way to indicate successful termination of their C
> programs."
> (Robert Firth)
>



-- 
"One of the main causes of the fall of the Roman Empire was that-lacking
zero-they had no way to indicate successful termination of their C
programs."
(Robert Firth)
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