Re: [be] bibledit-bin CPU usage

[Teus Benschop]

Hi Dan,

A fix for the CPU expense has been put in the local repository, to be
pushed out within 12 hours. It reduced the average CPU usage of
bibledit-bin from 2% on my laptop to 1% now. Which implies that you hit
the mail on the head when locating the routine that uses a lot of CPU
cycles. I'll submit a task, to be done later, to look into whether this
routine cannot be called only under certain circumstances rather than
once every so many milliseconds.

Thanks for your contribution.

Teus.

On Sat, 2009-01-31 at 16:47 -0800, Dan Dennison wrote:
> I ran bibledit-bin on Linux through callgrind, which is part of  
> valgrind.
> 
> It seems the bulk of its idle CPU usage is in the following fragment,  
> located in editor_aids.cpp:
> 
>    for (unsigned int i = 0; i < usfm->styles.size(); i++) {
>      if (marker == usfm->styles[i].marker) {
>        type = usfm->styles[i].type;
>        subtype = usfm->styles[i].subtype;
>        break;
>      }
>    }
> 
> This fragment is called every verse_tracker_timeout. Of the 51  
> verse_tracker_timeouts captured by my sample, 43,880 calls were made  
> to ustring::compare, which is called during evaluation of the if  
> statement. Quick math shows about 860 calls to a string comparison per  
> verse_tracker_timeout.
> 
> I think I might be possible to optimize the loop out completely by  
> using a hash table to do the lookup here. This is significant because  
> the idle CPU draw from bibledit-bin can be then further reduced,  
> allowing for even greater laptop battery life, crucial for some of our  
> deployment scenarios.
> 
> What do you think? My callgrind output is at https://thedennisons.org/ 
> ~dand/callgrind.out.19357.gz
> 
> dan :)
> 
> 
>