Re: [pygccxml-development] Performance problems and fixes

[Roman Y. <rom...@gm...>]

On 8/25/06, Allen Bierbaum <al...@vr...> wrote:
> Today I ran my generation script through the python hotspot profiler and
> found some interesting results.
>
> The majority of the time was being spent in algorithm.declaration_path.
> I fixed this up and double the speed of my script. :)

These are good news!

> After that I decided it may be worth investigating some other spots.

Before you do this, there is some work left on the previous patch :-(/

> What I have found is that the following areas are consuming a lot of
> time.  (not sure if it can be fixed or not, but this is where the time
> is spent)
>
> (all of these are in pygccxml)
> - Getting names from declarations
> - Testing declarations and calldefs for equality
> - Getting the decl_string (and creating it) for cpptypes.
>
> declarations.py  _get_name  line 151
> class_declarations.py _get_name_impl    line 105
> declaration.py  _eq_   line 119
> calldef.py  _eq_  line 121 and 53
> cpptypes.py  _get_decl_string   line 37
> algorithm.py   full_name   line 30
>
> Once I get into the office tomorrow I will upload my hotspot trace so
> other people can see what I ran into and hopefully find some other
> places to improve the performance of py++. :)

The issue that left.
Consider next use case ( a real one ).
I am not able to run a gccxml on boost.date_time library on windows. So
I run the gccxml on Linux and than use created xml file on Windows. The only
issue I has is next: there is a template class that is instantiated
with different values. So, on Windows I give class new name. Another
issue is free template
function on return type:

template< class X>
X do_smth(int, double);

int do_smth( int );

By default the generated code will not compile. User will have to rename
instantiated function to "do_smth<xyz>".

You can take a look on pyboost_dev/dev/date_time/generate_code.py script.

The point is that if user rename a declaration, the cache value you introduced
should be reset to None. In case of namespace and class the internal declaration
cache values should be reset too. If you don't do this, Py++ will generate bad
code and it will take a lot of time to find out the error.

The work, that still should be done:
1. To add new variable to declaration_t class.
2. To reset it and internal values on name change.
3. To write unit test ( pygccxml ).

Please, do this before you introduce another changes. Thank you.


-- 
Roman Yakovenko
C++ Python language binding
http://www.language-binding.net/