Re: [patch][rfa] --gprof Performance Improvement

[Dave Brolley <brolley@redhat.com>]

Frank Ch. Eigler wrote:

>Nicely done, thanks.  (If backward compatibility was at all a concern,
>the gprof component could have a new "sample" pin that assumes the
>pin-based PC traffic, instead of changing the current interface.  But
>I agree that the old interface is not worth saving.)
>
>Was the string conversion stuff obvious in profiling output?
>  
>
I don't know --- I took a more brute force approach, since I knew that 
the overhead was in the driving of the cpu's sample-gprof pin (the only 
effect of using --gprof). I first suspected overhead in the std::map 
used to collect the buckets, but that turned out to be small. I then 
tried the "local reference for this->stats[current_stats]" optimization 
and got the 3%. I then tried experimentally removing the collection of 
the data and found no improvement. That left the parsing of the 
attributes which, when experimentally removed, accounted for all of the 
nasty overhead.

Dave