Re: [gnugo-devel] yet another one speed optimization

[Paul Pogonyshev]

Arend Bayer wrote:
> Paul wrote:
> > here are the first few lines of a profile of gnugo 3.3.16-pre-3
> > on nngs2.tst:
> >
> > Each sample counts as 0.00195312 seconds.
> >   %   cumulative   self              self     total
> >  time   seconds   seconds    calls   s/call   s/call  name
> >  12.63 <<  57.15    57.15 133344624     0.00     0.00  scan_for_patterns
> >   4.98     79.70    22.55 175060566     0.00     0.00  fastlib
> >   4.16     98.52    18.82   320334     0.00     0.00 
> >  [...]
> >
> > i was quite surprised to see that scan_for_patterns() takes 12.5%
> > already. in the previous profile i made it was only about 7.5%.
> > maybe its a side effect on nando's recent patch - since tactical
> > reading now takes less time, scan_for_patterns() takes relatively
> > more. or maybe it's just because i now use gcc 3.2.
>
> Yes this is bad, and the problem will increase as processor speeds go up
> (as scan_for_patterns is mostly memory latency bound, whereas the rest
> of the code is mostly CPU bound). On what processor/RAM is this?

amd athlon-900, no idea what ram / bus speed (not interested in hardware ;).
just to note: i upgraded gcc, but the computer remained the same.

> > -/* perform pattern matching with dfa filtering */
> > +/* Perform pattern matching with dfa filtering. Sort patterns to keep
> > + * the same order as standard matcher.
> > + */
> >  static void
> >  do_dfa_matchpat(dfa_rt_t *pdfa,
> >             int anchor, matchpat_callback_fn_ptr callback,
> >
> > +
> > +#else /* !DFA_SORT */
> > +
> > +/* Perform pattern matching with dfa filtering. */
> > +static void
> > +do_dfa_matchpat(dfa_rt_t *pdfa,
> > +           int anchor, matchpat_callback_fn_ptr callback,
> > +           int color, struct pattern *database,
> > +           void *callback_data, char goal[BOARDMAX],
> > +                int anchor_in_goal)
>
> (...)
>
> This might be a good time to kill DFA_SORT. It is superceeded by the
> newer sorting algorithms in owl.c in my opinion (I don't think anyone
> has ever used this since it has been turned off by default).

i don't have any objections of course. just wanted to keep everything
in working state.

Paul