[pypy-issue] Issue #2845: tdigest with PyPy is 8x slower than with Python3 (pypy/pypy)

[Ovanes Markarian]

New issue 2845: tdigest with PyPy is 8x slower than with Python3
https://bitbucket.org/pypy/pypy/issues/2845/tdigest-with-pypy-is-8x-slower-than-with

Ovanes Markarian:

I ran the tests below and found out that on PyPy tdigest is horribly slow. Besides update I think all operations like merging of tdigests are slow. 

I opened a similar issue in tdigest GitHub: https://github.com/CamDavidsonPilon/tdigest/issues/44.

My timings are:


```
#!python

==========
PyPy
running test in 2.7.13 (0e7ea4fe15e82d5124e805e2e4a37cae1a402d4b, Jan 06 2018, 12:46:49)
[PyPy 5.10.0 with GCC 4.2.1 Compatible Apple LLVM 9.0.0 (clang-900.0.39.2)]
generating tdigests in batch
generated items: 100
generating tdigests took: 32.5672068596
----------
generating tdigests one by one
generated items: 100
generating tdigests took: 17.4209430218
----------

==================
Python
running test in 2.7.14 (default, Mar  9 2018, 23:57:12) 
[GCC 4.2.1 Compatible Apple LLVM 9.0.0 (clang-900.0.39.2)]
generating tdigests in batch
generated items: 100
generating tdigests took: 4.16117596626
----------
generating tdigests one by one
generated items: 100
generating tdigests took: 2.38711595535
----------
```


I've repeated the test in the official PyPy docker container with PyPy 6.0.0 (compatible with python 3) with the same outcome: https://hub.docker.com/_/pypy/

Any ideas?