[pypy-dev] Playing with PyPy and Django

Sun Feb 8 19:30:53 CET 2015

Hey Tin.

We are in the process of two (trivial) pull requests to django that
drop the rendering time from 25ms -> 8ms for this case. I'm not a
farseer, however I suspect something like this can be done with your
site too (depending what it really does).

On Sun, Feb 8, 2015 at 8:23 PM, Tin Tvrtković <tinchester at gmail.com> wrote:
> Hello,
>
> thanks to everyone for their input (especially Maciej).
>
> Since I've ripped out all my code from the test project, it's not a Python 3
> project anymore, so I did try PyPy 2 with it too. It's faster, yes; the last
> test looked something like:
>
> PyPy 2         20.206 [ms] (mean)
> PyPy 3         27.588 [ms] (mean)
> CPython 3.4    10.865 [ms] (mean)
>
> (tried both PyPy 2.5, downloaded directly, and 2.4 from the Ubuntu PPA -
> about the same.)
>
> I don't know, maybe the admin page isn't a good test candidate since it
> might do more introspective/reflective/meta stuff. I've tried doing this
> same test (10k warmup requests, 100 benchmark requests) on the main page of
> the site I'm working on; the results are:
>
> PyPy 3         15.863 [ms] (mean)
> CPython 3.48.668 [ms] (mean)
>
> and I can be certain there's nothing much going on there. Just some
> permission checks, grabbing some stuff from the database, checking some
> query parameters and a template render.
>
> I suppose if folks have CPU intensive stuff in their view functions (nested
> for-loops etc) the optimizations PyPy can do to that far outweigh the
> non-optimized Django parts; my sites generally don't though.
>
>
> On 08.02.2015 18:44, Maciej Fijalkowski wrote:
>>
>> then it's used in the wrong ways in say django admin, look at
>> invocations to lazy there (this is how it showed up in my profile)
>>
>> On Sun, Feb 8, 2015 at 5:08 PM, Alex Gaynor <alex.gaynor at gmail.com> wrote:
>>>
>>> FWIW, I've definitely seen and worked on Django sites that got major
>>> improvements out of PyPy -- both the templates and ORM are both sped up
>>> substantially by it. I think we should try to fix issues as we see them,
>>> before writing it off.
>>>
>>> FWIW: lazy does not create a new class per call of a function, it's only
>>> one
>>> class per decorated function.
>>>
>>> Alex
>>>
>>> On Sun, Feb 8, 2015 at 6:59 AM, Maciej Fijalkowski <fijall at gmail.com>
>>> wrote:
>>>>
>>>> I don't know :-( not sure if fixing those issues one by one is the way
>>>> to go, it's not like *this* particular code is a problem, it's the
>>>> culture that breeds those sort of things
>>>>
>>>> On Sun, Feb 8, 2015 at 2:09 PM, Omer Katz <omer.drow at gmail.com> wrote:
>>>>>
>>>>> Isn't there anything we can do about it?
>>>>> We can open issues at the Django issue tracker if some code slows down
>>>>> execution in PyPy.
>>>>>
>>>>> 2015-02-08 12:17 GMT+02:00 Maciej Fijalkowski <fijall at gmail.com>:
>>>>>>
>>>>>> Hi Tin
>>>>>>
>>>>>> I have a bit sad news for you, but essentially from what I looked at
>>>>>> profling, the answer seems to be "don't use django, it has not been
>>>>>> written with performance in mind". For example here (which features in
>>>>>> django admin quite prominently, some stuff calls lazy() at each call):
>>>>>>
>>>>>>
>>>>>>
>>>>>> https://github.com/django/django/blob/master/django/utils/functional.py#L48
>>>>>>
>>>>>> What does it, per call that pypy does not like:
>>>>>>
>>>>>> * redefines classes
>>>>>>
>>>>>> * walks the class __mro__ and defines tons of new methods
>>>>>>
>>>>>> * proxies everything through a not so efficietn mechanisms
>>>>>>
>>>>>> Those things quite defy the purpose of the JIT - you're making tons of
>>>>>> very dynamic things that pypy generally assumes is "static enough", if
>>>>>> you wanted to do the same thing in C++, you would need to call gcc
>>>>>> with each request, that would not be so much fun.
>>>>>>
>>>>>> If you really care about performance, consider swapping your web
>>>>>> framework to something more performance-oriented where JIT compilation
>>>>>> can help.
>>>>>>
>>>>>> As a side note, we (me and my company, not to be confused with PyPy
>>>>>> open source project) do offer looking at proprietary code for
>>>>>> benchmarking purposes as a commercial service, look at
>>>>>> baroquesoftware.com
>>>>>>
>>>>>> Cheers,
>>>>>> fijal
>>>>>>
>>>>>>
>>>>>>
>>>>>> On Sat, Feb 7, 2015 at 1:12 AM, Tin Tvrtković <tinchester at gmail.com>
>>>>>> wrote:
>>>>>>>
>>>>>>> Hello, PyPy folks!
>>>>>>>
>>>>>>> While trying to speed up one of my Django sites, I noticed a new
>>>>>>> version
>>>>>>> of
>>>>>>> PyPy
>>>>>>> had just been released. So I grabbed a fresh download of PyPy 3
>>>>>>> (since
>>>>>>> this
>>>>>>> is
>>>>>>> a Python 3 codebase) and tried taking it out for a spin.
>>>>>>>
>>>>>>> However, as far as I can see, whatever I try PyPy is consistently
>>>>>>> slower
>>>>>>> than
>>>>>>> CPython for this.
>>>>>>>
>>>>>>> Since this is a proprietary site, I've basically ripped out all the
>>>>>>> code
>>>>>>> except
>>>>>>> my settings.py and my requirements; and am benchmarking the Django
>>>>>>> admin
>>>>>>> index.
>>>>>>> The results are about the same.
>>>>>>>
>>>>>>> I've set up a small repo that can be used to reproduce the
>>>>>>> environment:
>>>>>>> https://github.com/Tinche/PyPy-Django-Playground. There's additional
>>>>>>> info in
>>>>>>> the README there.
>>>>>>>
>>>>>>> These tests have been carried out on Ubuntu Trusty, 64-bit. CPython 3
>>>>>>> is
>>>>>>> the
>>>>>>> system Python, 3.4. PyPy has been downloaded from the official site
>>>>>>> and
>>>>>>> unzipped.
>>>>>>>
>>>>>>> So what I basically do is set up an admin session, and use the Django
>>>>>>> main
>>>>>>> admin
>>>>>>> page. 200 warmup requests, then 100 benchmarked requests, look at the
>>>>>>> mean
>>>>>>> request time.
>>>>>>>
>>>>>>> Some results:
>>>>>>>
>>>>>>> Django's runserver, DEBUG mode:
>>>>>>>
>>>>>>> PyPy3            485.389 [ms]
>>>>>>> CPython 3.4      105.777 [ms]
>>>>>>>
>>>>>>> Django's runserver, no debug:
>>>>>>>
>>>>>>> PyPy3             44.661 [ms]
>>>>>>> CPython 3.4       18.697 [ms]
>>>>>>>
>>>>>>> Gunicorn, 1 worker, no debug:
>>>>>>>
>>>>>>> PyPy3             28.615 [ms]
>>>>>>> CPython 3.4       13.532 [ms]
>>>>>>>
>>>>>>> I don't exactly claim to be an expert on benchmarking, but assuming
>>>>>>> my
>>>>>>> site
>>>>>>> is similar to the Django admin, CPython's gonna be giving me better
>>>>>>> performance.
>>>>>>> Also the debug runserver performance is kinda worrying. Nobody's
>>>>>>> going
>>>>>>> to be
>>>>>>> running this in production, but it makes development a little slower
>>>>>>> and
>>>>>>> more
>>>>>>> annoying than it should be.
>>>>>>>
>>>>>>> Is there anything to make PyPy more competitive in these kinds of
>>>>>>> scenarios?
>>>>>>>
>>>>>>> Kind regards,
>>>>>>> Tin
>>>>>>> _______________________________________________
>>>>>>> pypy-dev mailing list
>>>>>>> pypy-dev at python.org
>>>>>>> https://mail.python.org/mailman/listinfo/pypy-dev
>>>>>>
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>>>>>
>>>>>
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>>>
>>>
>>>
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>
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