Re: profiling Octave

[Rik]

On 08/08/2019 09:50 PM, John W. Eaton wrote:
> On 8/9/19 12:30 AM, Rik wrote:
>> jwe,
>>
>> I wanted to look to look empirically at the slow down that has occurred
>> over time with Octave.
>>
>> I tried oprofile first, but even with some tweaking of the sampling
>> frequency I couldn't get high enough resolution to really see what needs to
>> be optimized.
>>
>> Since we're using GNU tools I thought I would just instrument the code by
>> compiling with -pg and then use gprof to examine things.  But, run-octave
>> quits immediately with "Profiling time alarm".  I suspect it is something
>> to do with uncaught signals and the way that the octave wrapper forks
>> immediately.
>>
>> As a final stab I tried Callgrind with 'run-octave -callgrind' but the
>> resulting log file is completely empty.  Probably, again, because it is
>> tracking the wrapper that forks rather than the true executable.
>>
>> Any ideas?
>
> If you are just looking at the interpreter speed and not the GUI, can you
> try the profiling tools with octave-cli?  It doesn't fork at startup.
>
Thanks, that helps.

With Callgrind, I can now get some results, although it is 70X slower than
the code running by itself so I can't do extensive tests.

When I run with gprof, there still seems to be an issue.  The flat profile is

  %   cumulative   self              self     total          
 time   seconds   seconds    calls  Ts/call  Ts/call  name   
  0.00      0.00     0.00        2     0.00     0.00 
__gnu_cxx::__enable_if<std::__is_char<char>::__value, bool>::__type
std::operator==<char>(std::__cxx11::basic_string<char,
std::char_traits<char>, std::allocator<char> > const&,
std::__cxx11::basic_string<char, std::char_traits<char>,
std::allocator<char> > const&)
  0.00      0.00     0.00        1     0.00     0.00  octave_hg_id[abi:cxx11]()
  0.00      0.00     0.00        1     0.00     0.00  main

for "gprof -p src/.libs/octave-cli".

This does seem to correspond with main-cli.cc which only contains main()
and the function check_hg_versions().  Is there another image file I can
give gprof?

--Rik






> jwe
>
>
>
>