[Developers] Double quotes around keyword parameter values

[Erik Schnetter]

On Sunday 29 May 2005 16:54, Jonathan Thornburg wrote:
> It would be interesting to see some actual profile data on this.

WaveToyFreeF90, checking the keyword parameter "bound" in the inner 
loop.  The relevant parts of the profile on my notebook (Intel P3, 1200 
MHz) read

Flat profile:

Each sample counts as 0.01 seconds.
  %   cumulative   self              self     total           
 time   seconds   seconds    calls   s/call   s/call  name    
 27.24     11.92     5.54     1200     0.00     0.01  
wavetoyfreef90_evolution_
 15.31     15.04     3.12 26346003     0.00     0.00  Util_StrMemCmpi
 12.05     17.48     2.45 26346003     0.00     0.00  cctk_equals_

When I check a pre-decoded keyword, this becomes:

Flat profile:

Each sample counts as 0.01 seconds.
  %   cumulative   self              self     total           
 time   seconds   seconds    calls   s/call   s/call  name    
 34.85     11.01     4.60     1200     0.00     0.00  
wavetoyfreef90_evolution_

The time spend in checking the keyword parameter is 2.1e-7 seconds per 
call, equivalent to about 250 cycles, however many instructions these 
are on my processor.

The physicist is interested in knowing that this slows down the 
evolution by more than a factor of two.  Other evolution systems are 
more expensive, so that the keyword checking is, relatively seen, less 
expensive, but other evolution systems may also want to check multiple 
keyword parameters.

-erik

-- 
Erik Schnetter <schnetter at aei.mpg.de>   http://www.aei.mpg.de/~eschnett/

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