On Wed, Nov 03, 2010 at 04:10:30PM -0400, Adam Jackson wrote: > On Wed, 2010-11-03 at 19:58 +0100, Jakub Jelinek wrote: > > On Wed, Nov 03, 2010 at 02:48:12PM -0400, Owen Taylor wrote: > > > Basically summarizes the situation, and as far as I know nothing has > > > changed ... with default compilation options, getting callgraph > > > profiling on x86_64 really requires a DWARF unwinder in the kernel. > > > Which seems unlikely to happen. > > > > But that's the right thing to do. > > Sure, but so is a kernel debugger, and it's taken us over ten years to > get one. I'm pretty okay with doing something wrong now if it gets me > something usable for long enough to get something right later. I'll > take 4% across the board if it helps me find the 20% that matters. Most of the time you don't find the 20% improvements with profilers though, so all we end up with is just slowing everything by 4%. Definitely a bad idea, now that per core performance doesn't increase very much and most programs aren't parallelized at all or just very badly. Jakub -- devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxxx https://admin.fedoraproject.org/mailman/listinfo/devel
