On Wed, 14 May 2008, David Miller wrote: > From: Steven Rostedt <[EMAIL PROTECTED]> > Date: Wed, 14 May 2008 23:49:44 -0400 > > > +#ifdef CONFIG_FTRACE > > +#ifdef CONFIG_DYNAMIC_FTRACE > > +_GLOBAL(mcount) > > +_GLOBAL(_mcount) > > + stwu r1,-48(r1) > > + stw r3, 12(r1) > > + stw r4, 16(r1) > > + stw r5, 20(r1) > > + stw r6, 24(r1) > > + mflr r3 > > + stw r7, 28(r1) > > + mfcr r5 > > + stw r8, 32(r1) > > + stw r9, 36(r1) > > + stw r10,40(r1) > > + stw r3, 44(r1) > > + stw r5, 8(r1) > > Yikes, that's really expensive.
Well, at least with dynamic ftrace, it's only expensive when tracing is enabled. > > Can't you do a tail call and let the function you end > up calling do all the callee-saved register pops onto > the stack? Not sure PPC has such a thing. I'm only a hobby PPC hacker (did it full time in another life). If there is such a way, I'll be happy to Ack any patches. > > That's what I did on sparc. > So that was your secret! ;-) -- Steve _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@ozlabs.org https://ozlabs.org/mailman/listinfo/linuxppc-dev
