OK, can you add that and/or maybe antons description to the patch changelog?
Mikey On Wed, Nov 6, 2013 at 9:21 PM, Philippe Bergheaud <fe...@linux.vnet.ibm.com> wrote: > Michael Neuling wrote: >> >> Philippe Bergheaud <fe...@linux.vnet.ibm.com> wrote: >> >> >>> Unaligned stores take alignment exceptions on POWER7 running in >>> little-endian. >>> This is a dumb little-endian base memcpy that prevents unaligned stores. >>> It is replaced by the VMX memcpy at boot. >> >> >> >> Is this any faster than the generic version? > > > The little-endian assembly code of the base memcpy is similar to the code > emitted by gcc when compiling the generic memcpy in lib/string.c, and runs > at the same speed. > However, a little-endian assembly version of the base memcpy is required (as > opposed to a C version), in order to use the self-modifying code > instrumentation system. > After the cpu feature CPU_FTR_ALTIVEC is detected at boot, the slow base > memcpy is nop'ed out, and the fast memcpy_power7 is used instead. > > Philippe > _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
