> On Sat, Jun 2, 2012 at 2:36 AM, Jan Hubicka <hubi...@ucw.cz> wrote: > >> Hi, > >> > >> This patch adds 4 flags to enable user to type in a list of name > >> patterns. Compiler will match the function name with the given > >> patterns, and add "hot", "cold", "likely_hot", "likely_cold" > >> attributes to function declaration. The static branch prediction > >> checks if a basic block contains call to a annotated function, and set > >> the branch probability accordingly. > >> > >> Bootstrapped and passed gcc testsuites. > >> > >> Ok for google branches? > > > > Just out of curiosity, what is main advantage of this over annotating your > > source? > > > > This is to avoid too much annotation at source level. Some > applications have good per application knowledge of library functions > (that are compiled and statically linked in). Another example of its > -- coarse grain (function level) profile data collected from data > center can be used to guide branch prediction/estimation.
Well, perhaps the feature would be more useful with command line option allowing to add an attribute instead of having special case command line options for individual cases. I guess the problem would be also solvable with header included after the library adding the attributes to the declarations typeof (printf) printf __attribute__ ((cold)); Honza > > thanks, > > David > > Honza
