[pypy-dev] Syscall Interface slowness

Dan Stromberg strombrg at gmail.com
Sat May 1 18:25:21 EDT 2021


The system that's faster with Pypy is a AMD FX(tm)-4300 Quad-Core Processor.

The system that's faster with CPython+Cython is a AMD Athlon(tm) II X3 455
Processor.


On Sat, May 1, 2021 at 3:08 PM Emre Yavuz <emre.yavuz169 at gmail.com> wrote:

> That’s really interesting! I also started to think it’s slower in I/O, I
> also run my tests in Ubuntu and Debian which resulted same.
>
> What type of system runs PyPy faster?
>
> Did you or someone have experience that and chance to look what’s making
> it slower? Because difference is huge when it comes to sys calls.
>
> I am planning to dive into the code to find out more if it’s not a known
> fact
>
> Best,
> Emre Yavuz
>
> On 1 May 2021, at 22:55, Dan Stromberg <strombrg at gmail.com> wrote:
>
>
> I have a system call-heavy program (
> https://stromberg.dnsalias.org/~strombrg/backshift/), that is faster with
> pypy on one machine, and faster with CPython+Cython on another.  Same code,
> different machines, different relative speeds for the two implementations.
>
> For a long time, I thought pypy was just faster at CPU and slower at I/O,
> but it turns out that's not always true.
>
> HTH.
>
> On Sat, May 1, 2021 at 1:50 PM Emre Yavuz <emre.yavuz169 at gmail.com> wrote:
>
>> Hello,
>>
>> Today I was doing some experiment with CPython and PyPy. I was very
>> impressed by the performance of PyPy, when it’s doing operations in user
>> space, it was almost 20 times faster than CPython.
>>
>> Then I decided to switch our Python CLI to PyPy and I run one of our
>> major command in our CLI and results were worse than CPython. It got
>> slower! Then I started to research it more. Our CLI’s characteristic is
>> that it calls multiple other programs and read a lot of configuration data
>> and create many files which mean all of those operations were related to
>> sys calls.
>>
>> Then I run some simple test cases, tried to read and write millions of
>> lines to a file or create and kill multiple processes. All of these
>> operations were almost 5 times slower than CPython. I run my tests both
>> MacOS and RHEL with latest version of PyPy3.7
>>
>> My question is that, is that something known? Or can it be some
>> improvement area that can be contributed?
>>
>> Best,
>> Emre Yavuz
>> _______________________________________________
>> pypy-dev mailing list
>> pypy-dev at python.org
>> https://mail.python.org/mailman/listinfo/pypy-dev
>>
>
>
> --
> Dan Stromberg
>
>
>

-- 
Dan Stromberg
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