[poky] Quick hack for profiling tasks

[Richard Purdie]

On Tue, 2011-02-01 at 00:28 +0000, Richard Purdie wrote:
> One thing that is bugging me whilst I've been debugging some issues
> we're having with the libc/libgcc package dependency issue is how long
> do_package takes for libc. The question is where does it spend the time?
> Answer, I have no idea.
> 
> I hacked together the patch below to find out. Its ugly and uses the
> boilerplate profiling code from cooker, cut and pasted here to profile
> the actual tasks that run.
> 
> I've yet to look at the results but it should allow us to optimise the
> python tasks a bit if we can see where they spend time. I'm hoping this
> lets others look at that too and also it give us some hints as to how we
> might improve the core when turning on profiling in bitbake.

For eglibc this worked out as:

Tue Feb  1 00:33:21 2011    profile-eglibc_2.12.bb-do_package.log

         8339733 function calls (8001600 primitive calls) in 877.972 CPU seconds

   Ordered by: internal time

   ncalls  tottime  percall  cumtime  percall filename:lineno(function)
     3206  321.887    0.100  322.422    0.101 package_do_filedeps:12(process_deps)
      403  311.208    0.772  311.208    0.772 {posix.waitpid}
   134054   69.860    0.001   69.860    0.001 {method 'read' of 'file' objects}
   225554   23.367    0.000   23.367    0.000 {posix.stat}
      866   20.279    0.023   20.279    0.023 {posix.system}
    85562   19.406    0.000   19.406    0.000 {posix.chmod}
   168083   16.691    0.000   16.691    0.000 {posix.lstat}
    25824   14.399    0.001   14.399    0.001 {posix.rename}
    55391   13.731    0.000   13.731    0.000 {open}
     5325    9.019    0.002    9.019    0.002 {posix.popen}
     2279    5.490    0.002    5.490    0.002 {method 'readlines' of 'file' objects}
     6403    5.187    0.001    6.346    0.001 insane.bbclass:1(package_qa_hash_style)
    19214    5.046    0.000    5.046    0.000 {posix.mkdir}

so its spending a third of the time in package_do_filedeps(), a lot of
which is in waitpid waiting for the process that was spawned.

Mark: Is there a way we could batch up the information rather than go
file by file? I'm going to look at this for other areas to improve too
but thats obviously one worthy of attention.

Cheers,

Richard