21 Feb
2015
21 Feb
'15
11:46 p.m.
Le 21/02/2015 23:18, Tudor Girba a écrit :
Hi,
On Sat, Feb 21, 2015 at 11:03 PM, Thierry Goubier
<thierry.goubier(a)gmail.com <mailto:thierry.goubier@gmail.com>> wrote:
Hi Doru,
the low hanging fruit is the time needed to create a PP parser (time
for new).
I still do not see the low hanging fruit. Do you have a concrete idea of
how to make it faster?
Look at that instantiation code, cache the result.
- Make a copy when you instantiate.
- Recreate / recompute if you execute a method extending the parser on
the resulting object.
- Have a copy parser method which cleanly creates a new instance.
(i.e. summarized as: new should memoize and make a copy of the memoized
version)
Or look into reflection for making some methods trigger code generation,
as if parser combinators were written in pragmas :)
I profiled PPSmalltalkParser over a bench used by Lucas Renggli a
few years ago, and PPSmalltalkParser spends half the time in "new"
(and it is a lot slower than it used to be).
What does "a lot slower" mean?
3 times slower in Pharo 4.
And this benchmark does not show any effect linked to long files; it's
only a list of fairly short methods (all Object and Morph methods).
Thierry