On Tue, 2011-09-20 at 16:02 +0200, Roland Scheidegger wrote: > Am 20.09.2011 12:35, schrieb Keith Whitwell: > > On Tue, 2011-09-20 at 10:59 +0200, Fabio wrote: > >> There was a discussion some months ago about using -fno-builtin-memcmp for > >> improving memcmp performance: > >> http://lists.freedesktop.org/archives/mesa-dev/2011-June/009078.html > >> > >> Since then, was it properly addressed in mesa or the flag is still > >> recommended? If so, what about adding it in configure.ac? > > > > I've been meaning to follow up on this too. I don't know the answer, > > but pinging Roland in case he does. > > I guess it is still recommended. > Ideally this is really something which should be fixed in gcc - the > compiler has all the knowledge about fixed alignment and size (if any) > (and more importantly knows if only a binary answer is needed which > makes this much easier) and doesn't need to do any function call. > If you enable that flag and some platform just has the same primitive > repz cmpsb sequence in the system library it will just get even slower, > though I guess chances of that happening are slim (with the possible > exception of windows). > I think in most cases it won't make much difference, so nobody cared to > implement that change. It is most likely still a good idea unless gcc > addressed that in the meantime...
Hmm, it seemed like it made a big difference in the earlier discussion... I should take a look at reducing the size of the struct (as mentioned before), but surely there's some way to pull in a better memcmp?? Keith _______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/mesa-dev
