>>> On 13.08.12 at 13:43, "Kirill A. Shutemov" >>> <kirill.shute...@linux.intel.com> wrote: > On Thu, Aug 09, 2012 at 04:22:04PM +0100, Jan Beulich wrote: >> >>> On 09.08.12 at 17:03, "Kirill A. Shutemov" >> >>> <kirill.shute...@linux.intel.com> wrote: > > ... > >> > --- >> > arch/x86/include/asm/page.h | 2 ++ >> > arch/x86/include/asm/string_32.h | 5 +++++ >> > arch/x86/include/asm/string_64.h | 5 +++++ >> > arch/x86/lib/Makefile | 1 + >> > arch/x86/lib/clear_page_nocache_32.S | 30 ++++++++++++++++++++++++++++++ >> > arch/x86/lib/clear_page_nocache_64.S | 29 +++++++++++++++++++++++++++++ >> >> Couldn't this more reasonably go into clear_page_{32,64}.S? > > We don't have clear_page_32.S.
Sure, but you're introducing a file anyway. Fold the new code into the existing file for 64-bit, and create a new, similarly named one for 32-bit. >> >+ xorl %eax,%eax >> >+ movl $4096/64,%ecx >> >+ .p2align 4 >> >+.Lloop: >> >+ decl %ecx >> >+#define PUT(x) movnti %eax,x*8(%edi) ; movnti %eax,x*8+4(%edi) >> >> Is doing twice as much unrolling as on 64-bit really worth it? > > Moving 64 bytes per cycle is faster on Sandy Bridge, but slower on > Westmere. Any preference? ;) If it's not a clear win, I'd favor the 8-stores-per-cycle variant, matching x86-64. Jan -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/