From: Paul Mackerras <paulus@xxxxxxxxx> Date: Fri, 19 Mar 2010 15:32:02 +1100 > On Thu, Mar 18, 2010 at 09:02:41PM -0700, David Miller wrote: >> I noticed that the powerpc assembler Paul posted the past few days >> ignores this "ip" arg passed down and computes it by hand as it >> walks up the stack chain in assembler. PowerPC therefore might be >> getting similar inefficiences due to this CALLER_ADDR? stuff. > > Well, it would except that CALLER_ADDR1, 2, etc. turn into (0) on > powerpc because we use the generic definition and we don't define > CONFIG_FRAME_POINTER (it's meaningless on powerpc because the ABI > defines that each stack frame always has a pointer to the previous > frame). > > I should fix CALLER_ADDRx on powerpc one day, then we will have the > extra inefficiency. Gosh, that CONFIG_FRAME_POINTER dependency is 'nifty', how does the CALLER_ADDR{1,2} usage made by the scheduler tracepoints work on powerpc then? I suppose I could define HAVE_ARCH_CALLER_ADDR and optimize them on sparc64, similar to what SH is doing. -- To unsubscribe from this list: send the line "unsubscribe linux-arch" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html