diff options
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/powerpc/lib/memcmp_64.S | 57 |
1 files changed, 46 insertions, 11 deletions
diff --git a/arch/powerpc/lib/memcmp_64.S b/arch/powerpc/lib/memcmp_64.S index be2f7925926b..844d8e774492 100644 --- a/arch/powerpc/lib/memcmp_64.S +++ b/arch/powerpc/lib/memcmp_64.S @@ -404,8 +404,27 @@ END_FTR_SECTION_IFSET(CPU_FTR_ARCH_207S) #ifdef CONFIG_ALTIVEC .Lsameoffset_vmx_cmp: /* Enter with src/dst addrs has the same offset with 8 bytes - * align boundary + * align boundary. + * + * There is an optimization based on following fact: memcmp() + * prones to fail early at the first 32 bytes. + * Before applying VMX instructions which will lead to 32x128bits + * VMX regs load/restore penalty, we compare the first 32 bytes + * so that we can catch the ~80% fail cases. */ + + li r0,4 + mtctr r0 +.Lsameoffset_prechk_32B_loop: + LD rA,0,r3 + LD rB,0,r4 + cmpld cr0,rA,rB + addi r3,r3,8 + addi r4,r4,8 + bne cr0,.LcmpAB_lightweight + addi r5,r5,-8 + bdnz .Lsameoffset_prechk_32B_loop + ENTER_VMX_OPS beq cr1,.Llong_novmx_cmp @@ -482,16 +501,6 @@ END_FTR_SECTION_IFSET(CPU_FTR_ARCH_207S) #endif .Ldiffoffset_8bytes_make_align_start: -#ifdef CONFIG_ALTIVEC -BEGIN_FTR_SECTION - /* only do vmx ops when the size equal or greater than 4K bytes */ - cmpdi cr5,r5,VMX_THRESH - bge cr5,.Ldiffoffset_vmx_cmp -END_FTR_SECTION_IFSET(CPU_FTR_ARCH_207S) - -.Ldiffoffset_novmx_cmp: -#endif - /* now try to align s1 with 8 bytes */ rlwinm r6,r3,3,26,28 beq .Ldiffoffset_align_s1_8bytes @@ -515,6 +524,17 @@ END_FTR_SECTION_IFSET(CPU_FTR_ARCH_207S) .Ldiffoffset_align_s1_8bytes: /* now s1 is aligned with 8 bytes. */ +#ifdef CONFIG_ALTIVEC +BEGIN_FTR_SECTION + /* only do vmx ops when the size equal or greater than 4K bytes */ + cmpdi cr5,r5,VMX_THRESH + bge cr5,.Ldiffoffset_vmx_cmp +END_FTR_SECTION_IFSET(CPU_FTR_ARCH_207S) + +.Ldiffoffset_novmx_cmp: +#endif + + cmpdi cr5,r5,31 ble cr5,.Lcmp_lt32bytes @@ -526,6 +546,21 @@ END_FTR_SECTION_IFSET(CPU_FTR_ARCH_207S) #ifdef CONFIG_ALTIVEC .Ldiffoffset_vmx_cmp: + /* perform a 32 bytes pre-checking before + * enable VMX operations. + */ + li r0,4 + mtctr r0 +.Ldiffoffset_prechk_32B_loop: + LD rA,0,r3 + LD rB,0,r4 + cmpld cr0,rA,rB + addi r3,r3,8 + addi r4,r4,8 + bne cr0,.LcmpAB_lightweight + addi r5,r5,-8 + bdnz .Ldiffoffset_prechk_32B_loop + ENTER_VMX_OPS beq cr1,.Ldiffoffset_novmx_cmp |