[BangPypers] BangPypers meeting February 2011

Fri Feb 11 07:33:17 CET 2011

Hi All,

Is tomorrow's meet confirmed? Anyone please post the details for the
meet-venue and time if things have changed from this
http://doodle.com/53iqx4gdu5fuzws7

Thanks,
Devjyoti

On Wed, Feb 9, 2011 at 4:30 PM,  <bangpypers-request at python.org> wrote:
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> Today's Topics:
>
>   1. Re: BangPypers meeting February 2011 (Baiju M)
>   2. Re: Ideas for Python concurrency... (Dhananjay Nene)
>   3. Re: Ideas for Python concurrency... (Vishal)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Tue, 8 Feb 2011 21:54:36 +0530
> From: Baiju M <baiju.m.mail at gmail.com>
> To: Bangalore Python Users Group - India <bangpypers at python.org>
> Subject: Re: [BangPypers] BangPypers meeting February 2011
> Message-ID:
>        <AANLkTinY_RCHa3PeOabr--mfaYseb_NcXsMzXuSoGvmc at mail.gmail.com>
> Content-Type: text/plain; charset=ISO-8859-1
>
> Hi All,
>
> Majority of the people are fine with Feb 12th (Saturday):
> http://doodle.com/53iqx4gdu5fuzws7
>
> So, we will have a regular meeting at 3 pm on that day.
> If more people are interested we can have a sprint
> otherwise we will go for normal discussions.
>
> Can anyone from ThoughtWorks confirm the venue
> availability ?
>
> Regards,
> Baiju M
>
>
> ------------------------------
>
> Message: 2
> Date: Wed, 9 Feb 2011 11:04:57 +0530
> From: Dhananjay Nene <dhananjay.nene at gmail.com>
> To: Bangalore Python Users Group - India <bangpypers at python.org>
> Subject: Re: [BangPypers] Ideas for Python concurrency...
> Message-ID:
>        <AANLkTikE1xSfMTff-2U1GzCL4TGtZOERE3z_SiXfv6nn at mail.gmail.com>
> Content-Type: text/plain; charset=ISO-8859-1
>
> On Tue, Feb 8, 2011 at 2:15 PM, Vishal <vsapre80 at gmail.com> wrote:
>
>> On Tue, Feb 8, 2011 at 2:10 PM, Baishampayan Ghose <b.ghose at gmail.com
>> >wrote:
>>
>> > > Mutliprocessing means, data copying, talking to each other through
>> PIPES,
>> > > also it has its issues with running on Windows (all function calls
>> should
>> > be pickelable)
>> > >
>> > > Threads seems pretty stable on most platforms where Python runs.
>> >
>> > Threads won't help you much because of the Python GIL.
>> >
>> > Regards,
>> > BG
>> >
>> > --
>> > Baishampayan Ghose
>> > b.ghose at gmail.com
>> > '
>> >
>>
>> The GIL is only limited to one interpreter. GIL comes into picture because
>> Threads in python create a new interpreter context, so the same interpreter
>> switches to new byte codes. The original idea was to create a new
>> interpreter for each thread, each one with its own GIL !!!. All within the
>> same process.
>>
>
> Interesting. But that does raise some curious issues of sharing data across
> interpreters.
> So as per the original thought - would threads be able to access data across
> multiple
> interpreters (to implement shared data), or would they have completely
> isolated
> data islands via message passing ?
>
> Dhananjay
>
>>
>> Vishal
>> _______________________________________________
>> BangPypers mailing list
>> BangPypers at python.org
>> http://mail.python.org/mailman/listinfo/bangpypers
>>
>
>
> ------------------------------
>
> Message: 3
> Date: Wed, 9 Feb 2011 14:16:24 +0530
> From: Vishal <vsapre80 at gmail.com>
> To: Bangalore Python Users Group - India <bangpypers at python.org>
> Subject: Re: [BangPypers] Ideas for Python concurrency...
> Message-ID:
>        <AANLkTimd3OkNDfBUs1S3DCNFfMJvQOiP-kU426mA60dN at mail.gmail.com>
> Content-Type: text/plain; charset=ISO-8859-1
>
> On Wed, Feb 9, 2011 at 11:04 AM, Dhananjay Nene <dhananjay.nene at gmail.com>wrote:
>
>> On Tue, Feb 8, 2011 at 2:15 PM, Vishal <vsapre80 at gmail.com> wrote:
>>
>> > On Tue, Feb 8, 2011 at 2:10 PM, Baishampayan Ghose <b.ghose at gmail.com
>> > >wrote:
>> >
>> > > > Mutliprocessing means, data copying, talking to each other through
>> > PIPES,
>> > > > also it has its issues with running on Windows (all function calls
>> > should
>> > > be pickelable)
>> > > >
>> > > > Threads seems pretty stable on most platforms where Python runs.
>> > >
>> > > Threads won't help you much because of the Python GIL.
>> > >
>> > > Regards,
>> > > BG
>> > >
>> > > --
>> > > Baishampayan Ghose
>> > > b.ghose at gmail.com
>> > > '
>> > >
>> >
>> > The GIL is only limited to one interpreter. GIL comes into picture
>> because
>> > Threads in python create a new interpreter context, so the same
>> interpreter
>> > switches to new byte codes. The original idea was to create a new
>> > interpreter for each thread, each one with its own GIL !!!. All within
>> the
>> > same process.
>> >
>>
>> Interesting. But that does raise some curious issues of sharing data across
>> interpreters.
>> So as per the original thought - would threads be able to access data
>> across
>> multiple
>> interpreters (to implement shared data), or would they have completely
>> isolated
>> data islands via message passing ?
>>
>> Dhananjay
>>
>>
> I had forwarded the same question to comp.lang.python. here are the replies
> till date:
> http://groups.google.com/group/comp.lang.python/browse_thread/thread/dd3938282b64c6ac/4a9d53c02e30cc3b#4a9d53c02e30cc3b
>
> <http://groups.google.com/group/comp.lang.python/browse_thread/thread/dd3938282b64c6ac/4a9d53c02e30cc3b#4a9d53c02e30cc3b>People
> have pointed out to the need of very fine grained locking that would be
> necessary to make sure data sharing is sane, between the interpreters.
> However, reference counting comes in the way of such a fine grained locking.
> People have also pointed towards PyPy which does away with reference
> counting.
>
> I like your comment about having an internal message passing scheme among
> the interpreters, like what processor cores do, when they have to share data
> through L2 caches.
>
> Best regards,
> Vishal Sapre.
>
>
> "May we do good and not evil. May we find forgiveness for ourself and
> forgive others. May we share freely, never taking more than we give."
>
>
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> End of BangPypers Digest, Vol 42, Issue 21
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>