Re: [pygccxml-development] Re: recent changes to pygccxml\pyplusplus

[Matthias B. <ba...@ir...>]

Allen Bierbaum wrote:
> I don't know if this would help you or not, but one thing I found that 
> helped my cache performance greatly (and was on of the reasons I 
> refactored the code to use md5 signatures) was that I could create a 
> temporary header file that included all the headers I wanted to parse.  
> Then I included that file instead of using a full "project" of header 
> files.  This made it so gccxml only ran once and it removed all the 
> redundancy of seeing the same decls from multiple included headers.  
> This was able to help me take a parse that was around 2 hours down to 
> about 1.5 minutes.  Overall a very good improvement in speed. :)

Wow, you're right! Using a single temporary header I get the following 
timings:

Without cache: 12s
File cache: 4s  (cache size: 3.1MB)
Dir cache:  2s  (cache size: 2.4MB)

2 seconds for parsing 222 header files is absolutely ok with me. :)

And now I finally understand what the compilation mode ALL_AT_ONCE as 
opposed to FILE_BY_FILE actually does (unfortunately, it doesn't use the 
cache, so it's still more efficient to use FILE_BY_FILE and create a 
temporary header file manually. This should be fixed eventually and once 
this is fixed, ALL_AT_ONCE should probably be default).

Now my new cache class is not as useful anymore as I thought, but as 
it's still smaller and faster than the file cache I committed it anyway.

- Matthias -