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https://github.com/edk2-porting/linux-next.git
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fde69282b7
Implement a POWER7 optimised copy_page using VMX and enhanced prefetch instructions. We use enhanced prefetch hints to prefetch both the load and store side. We copy a cacheline at a time and fall back to regular loads and stores if we are unable to use VMX (eg we are in an interrupt). The following microbenchmark was used to assess the impact of the patch: http://ozlabs.org/~anton/junkcode/page_fault_file.c We test MAP_PRIVATE page faults across a 1GB file, 100 times: # time ./page_fault_file -p -l 1G -i 100 Before: 22.25s After: 18.89s 17% faster Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
113 lines
2.1 KiB
ArmAsm
113 lines
2.1 KiB
ArmAsm
/*
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* Copyright (C) 2008 Mark Nelson, IBM Corp.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#include <asm/page.h>
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#include <asm/processor.h>
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#include <asm/ppc_asm.h>
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#include <asm/asm-offsets.h>
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.section ".toc","aw"
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PPC64_CACHES:
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.tc ppc64_caches[TC],ppc64_caches
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.section ".text"
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_GLOBAL(copy_page)
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BEGIN_FTR_SECTION
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lis r5,PAGE_SIZE@h
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FTR_SECTION_ELSE
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b .copypage_power7
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ALT_FTR_SECTION_END_IFCLR(CPU_FTR_VMX_COPY)
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ori r5,r5,PAGE_SIZE@l
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BEGIN_FTR_SECTION
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ld r10,PPC64_CACHES@toc(r2)
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lwz r11,DCACHEL1LOGLINESIZE(r10) /* log2 of cache line size */
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lwz r12,DCACHEL1LINESIZE(r10) /* get cache line size */
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li r9,0
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srd r8,r5,r11
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mtctr r8
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.Lsetup:
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dcbt r9,r4
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dcbz r9,r3
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add r9,r9,r12
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bdnz .Lsetup
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END_FTR_SECTION_IFSET(CPU_FTR_CP_USE_DCBTZ)
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addi r3,r3,-8
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srdi r8,r5,7 /* page is copied in 128 byte strides */
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addi r8,r8,-1 /* one stride copied outside loop */
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mtctr r8
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ld r5,0(r4)
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ld r6,8(r4)
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ld r7,16(r4)
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ldu r8,24(r4)
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1: std r5,8(r3)
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std r6,16(r3)
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ld r9,8(r4)
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ld r10,16(r4)
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std r7,24(r3)
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std r8,32(r3)
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ld r11,24(r4)
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ld r12,32(r4)
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std r9,40(r3)
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std r10,48(r3)
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ld r5,40(r4)
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ld r6,48(r4)
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std r11,56(r3)
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std r12,64(r3)
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ld r7,56(r4)
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ld r8,64(r4)
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std r5,72(r3)
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std r6,80(r3)
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ld r9,72(r4)
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ld r10,80(r4)
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std r7,88(r3)
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std r8,96(r3)
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ld r11,88(r4)
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ld r12,96(r4)
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std r9,104(r3)
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std r10,112(r3)
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ld r5,104(r4)
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ld r6,112(r4)
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std r11,120(r3)
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stdu r12,128(r3)
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ld r7,120(r4)
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ldu r8,128(r4)
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bdnz 1b
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std r5,8(r3)
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std r6,16(r3)
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ld r9,8(r4)
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ld r10,16(r4)
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std r7,24(r3)
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std r8,32(r3)
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ld r11,24(r4)
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ld r12,32(r4)
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std r9,40(r3)
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std r10,48(r3)
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ld r5,40(r4)
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ld r6,48(r4)
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std r11,56(r3)
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std r12,64(r3)
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ld r7,56(r4)
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ld r8,64(r4)
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std r5,72(r3)
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std r6,80(r3)
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ld r9,72(r4)
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ld r10,80(r4)
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std r7,88(r3)
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std r8,96(r3)
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ld r11,88(r4)
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ld r12,96(r4)
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std r9,104(r3)
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std r10,112(r3)
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std r11,120(r3)
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std r12,128(r3)
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blr
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