[Scons-users] SCons, CPython, PyPy

[Russel Winder]

On Wed, 2013-05-08 at 22:34 +0200, Gour wrote:
[…]

> 

> Considering that often SCons is cited as gret build system which can become

> slow, running under PyPy looks as easy way to optimize performance.

> 

> However, PyPy compatibility list

> (https://bitbucket.org/pypy/compatibility/wiki/scons) says: "SCons is not

> compatible with PyPy. A large part of its test suite fail under recent PyPy

> versions."

> 

> Anyone can shed some more light on it?


I used to run SCons with PyPy 1.9 by default, but there was a hiccup so
switched back to using CPython 2.7. I cannot remember details but I will
try again. As to SCons tests failing with PyPy then either:

	1. The test is wrong.
	2. PyPy is broken.
	3. CPython is broken.
	4. SCons is broken.

Both CPython 2.7 and PyPy 1.9 claim to be Python 2.7 compliant so the
easy hypothesis is that SCons is using Python that is not Python 2.7
compliant.

Given that the floor for SCons is now 2.7, we can start eradicating all
2.6 and earlier hacks and workarounds. This should help with PyPy
support. The question is getting people to actually amend the SCons code
base to remove stuff. I have been recalcitrant myself, but hopefully can
get stuck in from August.

On the other hand, why should PyPy be of benefit here? PyPy is 5 to 30
times faster than CPython executing compute-bound Python code, but most
of SCons is I/O and graph traversal.

-- 
Russel.
=============================================================================
Dr Russel Winder      t: +44 20 7585 2200   voip: sip:russel.winder at ekiga.net
41 Buckmaster Road    m: +44 7770 465 077   xmpp: russel at winder.org.uk
London SW11 1EN, UK   w: www.russel.org.uk  skype: russel_winder
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