Re: [pygccxml-development] Performance problems and fixes

[Allen B. <al...@vr...>]

Roman Yakovenko wrote:

> 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.

I sounds like you understand these issues much more then I do.  I don't 
even think I can replicate the problem you describe since I don't 
understand it.  If you can check in a testcase that causes the problem, 
I could look at it but otherwise I think I am going to need you to make 
these changes.

-Allen

>
>