Re: [PATCH v2 2/2] powerpc/32be: use stmw/lmw for registers save/restore in asm

2018-05-17 Thread Segher Boessenkool
On Thu, May 17, 2018 at 03:27:37PM +0200, Christophe LEROY wrote: > Le 17/05/2018 à 15:15, Segher Boessenkool a écrit : > >>I guess we've been enabling this for all 32-bit targets for ever so it > >>must be a reasonable option. > > > >On 603, load multiple (and string) are one cycle slower than

Re: [PATCH v2 2/2] powerpc/32be: use stmw/lmw for registers save/restore in asm

2018-05-17 Thread Benjamin Herrenschmidt
On Thu, 2018-05-17 at 22:10 +1000, Michael Ellerman wrote: > Christophe Leroy writes: > > arch/powerpc/Makefile activates -mmultiple on BE PPC32 configs > > in order to use multiple word instructions in functions entry/exit > > True, though that could be a lot simpler

Re: [PATCH v2 2/2] powerpc/32be: use stmw/lmw for registers save/restore in asm

2018-05-17 Thread Christophe LEROY
Le 17/05/2018 à 15:15, Segher Boessenkool a écrit : On Thu, May 17, 2018 at 10:10:21PM +1000, Michael Ellerman wrote: Christophe Leroy writes: arch/powerpc/Makefile activates -mmultiple on BE PPC32 configs in order to use multiple word instructions in functions

Re: [PATCH v2 2/2] powerpc/32be: use stmw/lmw for registers save/restore in asm

2018-05-17 Thread Segher Boessenkool
On Thu, May 17, 2018 at 10:10:21PM +1000, Michael Ellerman wrote: > Christophe Leroy writes: > > arch/powerpc/Makefile activates -mmultiple on BE PPC32 configs > > in order to use multiple word instructions in functions entry/exit > > True, though that could be a lot

Re: [PATCH v2 2/2] powerpc/32be: use stmw/lmw for registers save/restore in asm

2018-05-17 Thread Michael Ellerman
Christophe Leroy writes: > arch/powerpc/Makefile activates -mmultiple on BE PPC32 configs > in order to use multiple word instructions in functions entry/exit True, though that could be a lot simpler because the MULTIPLEWORD value is only used for PPC32, which is always

[PATCH v2 2/2] powerpc/32be: use stmw/lmw for registers save/restore in asm

2018-04-17 Thread Christophe Leroy
arch/powerpc/Makefile activates -mmultiple on BE PPC32 configs in order to use multiple word instructions in functions entry/exit The patch does the same for the asm parts, for consistency On processors like the 8xx on which insn fetching is pretty slow, this speeds up registers save/restore