On Wed, Dec 06, 2006 at 03:21:23PM +0000, Kirsten Chevalier wrote: > On 12/6/06, Serge D. Mechveliani <[EMAIL PROTECTED]> wrote: > >What may consitute this strange CAF cost of 96% ? > > > >Kirsten Chevalier <[EMAIL PROTECTED]> > >wrote > >> I didn't look at your code all that carefully, but did you build the > >> GHC libraries with "-prof -auto-all"? (Not just "-prof".) If you don't > >> build the libraries with "-auto-all", then cost centres won't get > >> inserted for library functions, and if it's really a standard library > >> function that's taking all of that time, the profiling report won't > >> indicate that. > > > >I made ghc-6.6 from the official source in a standard way: > > > > ./configure ...; make; make install > > > >Does this presume that this also generates the .p.o GHC library versions > >for -prof -auto-all ? > > > > No; you must have built the profiling libraries (i.e., building the > libraries with -prof), otherwise you wouldn't have been able to > compile your code for profiling. But, building the profiling libraries > in the standard way doesn't add "-auto-all" to the compile flags. So > if you want to build the libraries with "-auto-all", do: > make EXTRA_HC_OPTS=-auto-all
Thank you. I am trying this. One could ask, why the GHC installation does not apply -auto-all by default? > but be careful! As I said in my previous message, adding cost centres > disables some optimizations, so the profiling results you get from > this may not be accurate with respect to what would happen if you ran > your code after building it with -O and no profiling. In my example, -O makes the run 2 times faster, and the profiling time per-cents are shown the same as for -Onot. I suspect that this particular invilisible time eater will present independently on -O flag and on the cost centers. ----------------- Serge Mechveliani [EMAIL PROTECTED] _______________________________________________ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
