On Sun, Jul 20, 2014 at 02:19:01PM -0700, Andi Kleen wrote: > > Why are as only called with -Wa,-gdwarf-2 in the non-split case? > > Is this a bug or intentional? > > If it is intentional then it is not explained. > > Probably was a merging mistake. Will fix. > > > > + help > > > + Generate debug info into separate .dwo files. This can be > > > + faster for building than including the debug information directly > > Here the "faster" part is promoted. > > But in your cover letter you actually highlight the "smaller" case > > as more significant. > > Maybe include info on both positive items. > > I currently don't see it significantly faster in my setup, will > mention size. It may be in others though. Feel free to test. I tried to test this on my setup - it is a Intel Atom with 2 cores. 16 GB RAM, a 7200 RPM stat disk. In other words a low-spec setup. Base config was "make allnoconfig" make KCFLAGS=-g real 3m35.967s user 12m19.270s sys 1m15.082s make KCFLAGS=-gsplit-dwarf real 3m33.366s user 12m11.156s sys 1m17.772s I did like this: echo time make -j4 -s KCFLAGS=-gsplit-dwarf time make -j4 -s KCFLAGS=-gsplit-dwarf echo time make -j4 -s KCFLAGS=-g time make -j4 -s KCFLAGS=-g echo time make -j4 -s KCFLAGS=-gsplit-dwarf time make -j4 -s KCFLAGS=-gsplit-dwarf echo time make -j4 -s KCFLAGS=-g time make -j4 -s KCFLAGS=-g echo time make -j4 -s KCFLAGS=-gsplit-dwarf time make -j4 -s KCFLAGS=-gsplit-dwarf echo time make -j4 -s KCFLAGS=-g time make -j4 -s KCFLAGS=-g The figures are from last run - but the other runs had compareable times. So in short I see a ~3 seconds speedup - out of 210 seconds. Thats less than I anticipated. But a speed-up never the less - which was consistent over all three runs. Sam -- To unsubscribe from this list: send the line "unsubscribe linux-kbuild" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
