[pypy-dev] Syscall Interface slowness

[Carl Friedrich Bolz-Tereick]

Hi Emre,

IO can definitely be slower than CPython, but not in all cases. A few of
them are known and we try to improve them, eg readline operations on
files:

https://foss.heptapod.net/pypy/pypy/-/issues/3126

5x is definitely too much of a difference, if you can minimize that to a
small self-contained example, that would be a very valuable bug report
and we would definitely try to fix it.

Cheers,

Carl Friedrich

On 5/1/21 10:50 PM, Emre Yavuz 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
>
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