On Wed, 18 Aug 2010, David Miller wrote: > From: Mikulas Patocka <mpatocka@xxxxxxxxxx> > Date: Wed, 18 Aug 2010 14:03:37 -0400 (EDT) > > > Simple microoptimizations for sparc64 atomic functions: > > Save one instruction by using a delay slot. > > Use %g1 instead of %g7, because %g1 is written earlier. > > > > Signed-off-by: Mikulas Patocka <mpatocka@xxxxxxxxxx> > > Does it really make things faster? What timings have you > done on these code sequences? I don't think such microoptimizations can be measured. It may save an I-cacheline --- but who knows if exactly this cacheline makes some effect or not? The point is that making microoptimizations is *much* easier than measuring them, so I usually do them and never ask if they help. If you do 100 microoptimizations, it may have some effect in code size reduction, but you never pinpoint it to a single optimization. Mikulas -- To unsubscribe from this list: send the line "unsubscribe sparclinux" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
