From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Thu, 31 May 2012 16:22:09 +1000 From: Anton Blanchard To: benh@kernel.crashing.org, paulus@samba.org, michael@ellerman.id.au Subject: [PATCH] powerpc: POWER7 optimised memcpy using VMX and enhanced prefetch Message-ID: <20120531162209.04bd9bdc@kryten> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Cc: linuxppc-dev@lists.ozlabs.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Implement a POWER7 optimised memcpy using VMX and enhanced prefetch instructions. This is a copy of the POWER7 optimised copy_to_user/copy_from_user loop. Detailed implementation and performance details can be found in commit a66086b8197d (powerpc: POWER7 optimised copy_to_user/copy_from_user using VMX). I noticed memcpy issues when profiling a RAID6 workload: .memcpy .async_memcpy .async_copy_data .__raid_run_ops .handle_stripe .raid5d .md_thread I created a simplified testcase by building a RAID6 array with 4 1GB ramdisks (booting with brd.rd_size=1048576): # mdadm -CR -e 1.2 /dev/md0 --level=6 -n4 /dev/ram[0-3] I then timed how long it took to write to the entire array: # dd if=/dev/zero of=/dev/md0 bs=1M Before: 892 MB/s After: 999 MB/s A 12% improvement. Signed-off-by: Anton Blanchard --- Index: linux-build/arch/powerpc/lib/Makefile =================================================================== --- linux-build.orig/arch/powerpc/lib/Makefile 2012-05-30 15:27:30.000000000 +1000 +++ linux-build/arch/powerpc/lib/Makefile 2012-05-31 09:12:27.574372864 +1000 @@ -17,7 +17,8 @@ obj-$(CONFIG_HAS_IOMEM) += devres.o obj-$(CONFIG_PPC64) += copypage_64.o copyuser_64.o \ memcpy_64.o usercopy_64.o mem_64.o string.o \ checksum_wrappers_64.o hweight_64.o \ - copyuser_power7.o string_64.o copypage_power7.o + copyuser_power7.o string_64.o copypage_power7.o \ + memcpy_power7.o obj-$(CONFIG_XMON) += sstep.o ldstfp.o obj-$(CONFIG_KPROBES) += sstep.o ldstfp.o obj-$(CONFIG_HAVE_HW_BREAKPOINT) += sstep.o ldstfp.o Index: linux-build/arch/powerpc/lib/memcpy_64.S =================================================================== --- linux-build.orig/arch/powerpc/lib/memcpy_64.S 2012-05-30 09:39:59.000000000 +1000 +++ linux-build/arch/powerpc/lib/memcpy_64.S 2012-05-31 09:12:00.093876936 +1000 @@ -11,7 +11,11 @@ .align 7 _GLOBAL(memcpy) +BEGIN_FTR_SECTION std r3,48(r1) /* save destination pointer for return value */ +FTR_SECTION_ELSE + b memcpy_power7 +ALT_FTR_SECTION_END_IFCLR(CPU_FTR_VMX_COPY) PPC_MTOCRF(0x01,r5) cmpldi cr1,r5,16 neg r6,r3 # LS 3 bits = # bytes to 8-byte dest bdry Index: linux-build/arch/powerpc/lib/memcpy_power7.S =================================================================== --- /dev/null 1970-01-01 00:00:00.000000000 +0000 +++ linux-build/arch/powerpc/lib/memcpy_power7.S 2012-05-31 15:28:03.495781127 +1000 @@ -0,0 +1,650 @@ +/* + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. + * + * Copyright (C) IBM Corporation, 2012 + * + * Author: Anton Blanchard + */ +#include + +#define STACKFRAMESIZE 256 +#define STK_REG(i) (112 + ((i)-14)*8) + +_GLOBAL(memcpy_power7) +#ifdef CONFIG_ALTIVEC + cmpldi r5,16 + cmpldi cr1,r5,4096 + + std r3,48(r1) + + blt .Lshort_copy + bgt cr1,.Lvmx_copy +#else + cmpldi r5,16 + + std r3,48(r1) + + blt .Lshort_copy +#endif + +.Lnonvmx_copy: + /* Get the source 8B aligned */ + neg r6,r4 + mtocrf 0x01,r6 + clrldi r6,r6,(64-3) + + bf cr7*4+3,1f + lbz r0,0(r4) + addi r4,r4,1 + stb r0,0(r3) + addi r3,r3,1 + +1: bf cr7*4+2,2f + lhz r0,0(r4) + addi r4,r4,2 + sth r0,0(r3) + addi r3,r3,2 + +2: bf cr7*4+1,3f + lwz r0,0(r4) + addi r4,r4,4 + stw r0,0(r3) + addi r3,r3,4 + +3: sub r5,r5,r6 + cmpldi r5,128 + blt 5f + + mflr r0 + stdu r1,-STACKFRAMESIZE(r1) + std r14,STK_REG(r14)(r1) + std r15,STK_REG(r15)(r1) + std r16,STK_REG(r16)(r1) + std r17,STK_REG(r17)(r1) + std r18,STK_REG(r18)(r1) + std r19,STK_REG(r19)(r1) + std r20,STK_REG(r20)(r1) + std r21,STK_REG(r21)(r1) + std r22,STK_REG(r22)(r1) + std r0,STACKFRAMESIZE+16(r1) + + srdi r6,r5,7 + mtctr r6 + + /* Now do cacheline (128B) sized loads and stores. */ + .align 5 +4: + ld r0,0(r4) + ld r6,8(r4) + ld r7,16(r4) + ld r8,24(r4) + ld r9,32(r4) + ld r10,40(r4) + ld r11,48(r4) + ld r12,56(r4) + ld r14,64(r4) + ld r15,72(r4) + ld r16,80(r4) + ld r17,88(r4) + ld r18,96(r4) + ld r19,104(r4) + ld r20,112(r4) + ld r21,120(r4) + addi r4,r4,128 + std r0,0(r3) + std r6,8(r3) + std r7,16(r3) + std r8,24(r3) + std r9,32(r3) + std r10,40(r3) + std r11,48(r3) + std r12,56(r3) + std r14,64(r3) + std r15,72(r3) + std r16,80(r3) + std r17,88(r3) + std r18,96(r3) + std r19,104(r3) + std r20,112(r3) + std r21,120(r3) + addi r3,r3,128 + bdnz 4b + + clrldi r5,r5,(64-7) + + ld r14,STK_REG(r14)(r1) + ld r15,STK_REG(r15)(r1) + ld r16,STK_REG(r16)(r1) + ld r17,STK_REG(r17)(r1) + ld r18,STK_REG(r18)(r1) + ld r19,STK_REG(r19)(r1) + ld r20,STK_REG(r20)(r1) + ld r21,STK_REG(r21)(r1) + ld r22,STK_REG(r22)(r1) + addi r1,r1,STACKFRAMESIZE + + /* Up to 127B to go */ +5: srdi r6,r5,4 + mtocrf 0x01,r6 + +6: bf cr7*4+1,7f + ld r0,0(r4) + ld r6,8(r4) + ld r7,16(r4) + ld r8,24(r4) + ld r9,32(r4) + ld r10,40(r4) + ld r11,48(r4) + ld r12,56(r4) + addi r4,r4,64 + std r0,0(r3) + std r6,8(r3) + std r7,16(r3) + std r8,24(r3) + std r9,32(r3) + std r10,40(r3) + std r11,48(r3) + std r12,56(r3) + addi r3,r3,64 + + /* Up to 63B to go */ +7: bf cr7*4+2,8f + ld r0,0(r4) + ld r6,8(r4) + ld r7,16(r4) + ld r8,24(r4) + addi r4,r4,32 + std r0,0(r3) + std r6,8(r3) + std r7,16(r3) + std r8,24(r3) + addi r3,r3,32 + + /* Up to 31B to go */ +8: bf cr7*4+3,9f + ld r0,0(r4) + ld r6,8(r4) + addi r4,r4,16 + std r0,0(r3) + std r6,8(r3) + addi r3,r3,16 + +9: clrldi r5,r5,(64-4) + + /* Up to 15B to go */ +.Lshort_copy: + mtocrf 0x01,r5 + bf cr7*4+0,12f + lwz r0,0(r4) /* Less chance of a reject with word ops */ + lwz r6,4(r4) + addi r4,r4,8 + stw r0,0(r3) + stw r6,4(r3) + addi r3,r3,8 + +12: bf cr7*4+1,13f + lwz r0,0(r4) + addi r4,r4,4 + stw r0,0(r3) + addi r3,r3,4 + +13: bf cr7*4+2,14f + lhz r0,0(r4) + addi r4,r4,2 + sth r0,0(r3) + addi r3,r3,2 + +14: bf cr7*4+3,15f + lbz r0,0(r4) + stb r0,0(r3) + +15: ld r3,48(r1) + blr + +.Lunwind_stack_nonvmx_copy: + addi r1,r1,STACKFRAMESIZE + b .Lnonvmx_copy + +#ifdef CONFIG_ALTIVEC +.Lvmx_copy: + mflr r0 + std r4,56(r1) + std r5,64(r1) + std r0,16(r1) + stdu r1,-STACKFRAMESIZE(r1) + bl .enter_vmx_copy + cmpwi r3,0 + ld r0,STACKFRAMESIZE+16(r1) + ld r3,STACKFRAMESIZE+48(r1) + ld r4,STACKFRAMESIZE+56(r1) + ld r5,STACKFRAMESIZE+64(r1) + mtlr r0 + + /* + * We prefetch both the source and destination using enhanced touch + * instructions. We use a stream ID of 0 for the load side and + * 1 for the store side. + */ + clrrdi r6,r4,7 + clrrdi r9,r3,7 + ori r9,r9,1 /* stream=1 */ + + srdi r7,r5,7 /* length in cachelines, capped at 0x3FF */ + cmpldi cr1,r7,0x3FF + ble cr1,1f + li r7,0x3FF +1: lis r0,0x0E00 /* depth=7 */ + sldi r7,r7,7 + or r7,r7,r0 + ori r10,r7,1 /* stream=1 */ + + lis r8,0x8000 /* GO=1 */ + clrldi r8,r8,32 + +.machine push +.machine "power4" + dcbt r0,r6,0b01000 + dcbt r0,r7,0b01010 + dcbtst r0,r9,0b01000 + dcbtst r0,r10,0b01010 + eieio + dcbt r0,r8,0b01010 /* GO */ +.machine pop + + beq .Lunwind_stack_nonvmx_copy + + /* + * If source and destination are not relatively aligned we use a + * slower permute loop. + */ + xor r6,r4,r3 + rldicl. r6,r6,0,(64-4) + bne .Lvmx_unaligned_copy + + /* Get the destination 16B aligned */ + neg r6,r3 + mtocrf 0x01,r6 + clrldi r6,r6,(64-4) + + bf cr7*4+3,1f + lbz r0,0(r4) + addi r4,r4,1 + stb r0,0(r3) + addi r3,r3,1 + +1: bf cr7*4+2,2f + lhz r0,0(r4) + addi r4,r4,2 + sth r0,0(r3) + addi r3,r3,2 + +2: bf cr7*4+1,3f + lwz r0,0(r4) + addi r4,r4,4 + stw r0,0(r3) + addi r3,r3,4 + +3: bf cr7*4+0,4f + ld r0,0(r4) + addi r4,r4,8 + std r0,0(r3) + addi r3,r3,8 + +4: sub r5,r5,r6 + + /* Get the desination 128B aligned */ + neg r6,r3 + srdi r7,r6,4 + mtocrf 0x01,r7 + clrldi r6,r6,(64-7) + + li r9,16 + li r10,32 + li r11,48 + + bf cr7*4+3,5f + lvx vr1,r0,r4 + addi r4,r4,16 + stvx vr1,r0,r3 + addi r3,r3,16 + +5: bf cr7*4+2,6f + lvx vr1,r0,r4 + lvx vr0,r4,r9 + addi r4,r4,32 + stvx vr1,r0,r3 + stvx vr0,r3,r9 + addi r3,r3,32 + +6: bf cr7*4+1,7f + lvx vr3,r0,r4 + lvx vr2,r4,r9 + lvx vr1,r4,r10 + lvx vr0,r4,r11 + addi r4,r4,64 + stvx vr3,r0,r3 + stvx vr2,r3,r9 + stvx vr1,r3,r10 + stvx vr0,r3,r11 + addi r3,r3,64 + +7: sub r5,r5,r6 + srdi r6,r5,7 + + std r14,STK_REG(r14)(r1) + std r15,STK_REG(r15)(r1) + std r16,STK_REG(r16)(r1) + + li r12,64 + li r14,80 + li r15,96 + li r16,112 + + mtctr r6 + + /* + * Now do cacheline sized loads and stores. By this stage the + * cacheline stores are also cacheline aligned. + */ + .align 5 +8: + lvx vr7,r0,r4 + lvx vr6,r4,r9 + lvx vr5,r4,r10 + lvx vr4,r4,r11 + lvx vr3,r4,r12 + lvx vr2,r4,r14 + lvx vr1,r4,r15 + lvx vr0,r4,r16 + addi r4,r4,128 + stvx vr7,r0,r3 + stvx vr6,r3,r9 + stvx vr5,r3,r10 + stvx vr4,r3,r11 + stvx vr3,r3,r12 + stvx vr2,r3,r14 + stvx vr1,r3,r15 + stvx vr0,r3,r16 + addi r3,r3,128 + bdnz 8b + + ld r14,STK_REG(r14)(r1) + ld r15,STK_REG(r15)(r1) + ld r16,STK_REG(r16)(r1) + + /* Up to 127B to go */ + clrldi r5,r5,(64-7) + srdi r6,r5,4 + mtocrf 0x01,r6 + + bf cr7*4+1,9f + lvx vr3,r0,r4 + lvx vr2,r4,r9 + lvx vr1,r4,r10 + lvx vr0,r4,r11 + addi r4,r4,64 + stvx vr3,r0,r3 + stvx vr2,r3,r9 + stvx vr1,r3,r10 + stvx vr0,r3,r11 + addi r3,r3,64 + +9: bf cr7*4+2,10f + lvx vr1,r0,r4 + lvx vr0,r4,r9 + addi r4,r4,32 + stvx vr1,r0,r3 + stvx vr0,r3,r9 + addi r3,r3,32 + +10: bf cr7*4+3,11f + lvx vr1,r0,r4 + addi r4,r4,16 + stvx vr1,r0,r3 + addi r3,r3,16 + + /* Up to 15B to go */ +11: clrldi r5,r5,(64-4) + mtocrf 0x01,r5 + bf cr7*4+0,12f + ld r0,0(r4) + addi r4,r4,8 + std r0,0(r3) + addi r3,r3,8 + +12: bf cr7*4+1,13f + lwz r0,0(r4) + addi r4,r4,4 + stw r0,0(r3) + addi r3,r3,4 + +13: bf cr7*4+2,14f + lhz r0,0(r4) + addi r4,r4,2 + sth r0,0(r3) + addi r3,r3,2 + +14: bf cr7*4+3,15f + lbz r0,0(r4) + stb r0,0(r3) + +15: addi r1,r1,STACKFRAMESIZE + ld r3,48(r1) + b .exit_vmx_copy /* tail call optimise */ + +.Lvmx_unaligned_copy: + /* Get the destination 16B aligned */ + neg r6,r3 + mtocrf 0x01,r6 + clrldi r6,r6,(64-4) + + bf cr7*4+3,1f + lbz r0,0(r4) + addi r4,r4,1 + stb r0,0(r3) + addi r3,r3,1 + +1: bf cr7*4+2,2f + lhz r0,0(r4) + addi r4,r4,2 + sth r0,0(r3) + addi r3,r3,2 + +2: bf cr7*4+1,3f + lwz r0,0(r4) + addi r4,r4,4 + stw r0,0(r3) + addi r3,r3,4 + +3: bf cr7*4+0,4f + lwz r0,0(r4) /* Less chance of a reject with word ops */ + lwz r7,4(r4) + addi r4,r4,8 + stw r0,0(r3) + stw r7,4(r3) + addi r3,r3,8 + +4: sub r5,r5,r6 + + /* Get the desination 128B aligned */ + neg r6,r3 + srdi r7,r6,4 + mtocrf 0x01,r7 + clrldi r6,r6,(64-7) + + li r9,16 + li r10,32 + li r11,48 + + lvsl vr16,0,r4 /* Setup permute control vector */ + lvx vr0,0,r4 + addi r4,r4,16 + + bf cr7*4+3,5f + lvx vr1,r0,r4 + vperm vr8,vr0,vr1,vr16 + addi r4,r4,16 + stvx vr8,r0,r3 + addi r3,r3,16 + vor vr0,vr1,vr1 + +5: bf cr7*4+2,6f + lvx vr1,r0,r4 + vperm vr8,vr0,vr1,vr16 + lvx vr0,r4,r9 + vperm vr9,vr1,vr0,vr16 + addi r4,r4,32 + stvx vr8,r0,r3 + stvx vr9,r3,r9 + addi r3,r3,32 + +6: bf cr7*4+1,7f + lvx vr3,r0,r4 + vperm vr8,vr0,vr3,vr16 + lvx vr2,r4,r9 + vperm vr9,vr3,vr2,vr16 + lvx vr1,r4,r10 + vperm vr10,vr2,vr1,vr16 + lvx vr0,r4,r11 + vperm vr11,vr1,vr0,vr16 + addi r4,r4,64 + stvx vr8,r0,r3 + stvx vr9,r3,r9 + stvx vr10,r3,r10 + stvx vr11,r3,r11 + addi r3,r3,64 + +7: sub r5,r5,r6 + srdi r6,r5,7 + + std r14,STK_REG(r14)(r1) + std r15,STK_REG(r15)(r1) + std r16,STK_REG(r16)(r1) + + li r12,64 + li r14,80 + li r15,96 + li r16,112 + + mtctr r6 + + /* + * Now do cacheline sized loads and stores. By this stage the + * cacheline stores are also cacheline aligned. + */ + .align 5 +8: + lvx vr7,r0,r4 + vperm vr8,vr0,vr7,vr16 + lvx vr6,r4,r9 + vperm vr9,vr7,vr6,vr16 + lvx vr5,r4,r10 + vperm vr10,vr6,vr5,vr16 + lvx vr4,r4,r11 + vperm vr11,vr5,vr4,vr16 + lvx vr3,r4,r12 + vperm vr12,vr4,vr3,vr16 + lvx vr2,r4,r14 + vperm vr13,vr3,vr2,vr16 + lvx vr1,r4,r15 + vperm vr14,vr2,vr1,vr16 + lvx vr0,r4,r16 + vperm vr15,vr1,vr0,vr16 + addi r4,r4,128 + stvx vr8,r0,r3 + stvx vr9,r3,r9 + stvx vr10,r3,r10 + stvx vr11,r3,r11 + stvx vr12,r3,r12 + stvx vr13,r3,r14 + stvx vr14,r3,r15 + stvx vr15,r3,r16 + addi r3,r3,128 + bdnz 8b + + ld r14,STK_REG(r14)(r1) + ld r15,STK_REG(r15)(r1) + ld r16,STK_REG(r16)(r1) + + /* Up to 127B to go */ + clrldi r5,r5,(64-7) + srdi r6,r5,4 + mtocrf 0x01,r6 + + bf cr7*4+1,9f + lvx vr3,r0,r4 + vperm vr8,vr0,vr3,vr16 + lvx vr2,r4,r9 + vperm vr9,vr3,vr2,vr16 + lvx vr1,r4,r10 + vperm vr10,vr2,vr1,vr16 + lvx vr0,r4,r11 + vperm vr11,vr1,vr0,vr16 + addi r4,r4,64 + stvx vr8,r0,r3 + stvx vr9,r3,r9 + stvx vr10,r3,r10 + stvx vr11,r3,r11 + addi r3,r3,64 + +9: bf cr7*4+2,10f + lvx vr1,r0,r4 + vperm vr8,vr0,vr1,vr16 + lvx vr0,r4,r9 + vperm vr9,vr1,vr0,vr16 + addi r4,r4,32 + stvx vr8,r0,r3 + stvx vr9,r3,r9 + addi r3,r3,32 + +10: bf cr7*4+3,11f + lvx vr1,r0,r4 + vperm vr8,vr0,vr1,vr16 + addi r4,r4,16 + stvx vr8,r0,r3 + addi r3,r3,16 + + /* Up to 15B to go */ +11: clrldi r5,r5,(64-4) + addi r4,r4,-16 /* Unwind the +16 load offset */ + mtocrf 0x01,r5 + bf cr7*4+0,12f + lwz r0,0(r4) /* Less chance of a reject with word ops */ + lwz r6,4(r4) + addi r4,r4,8 + stw r0,0(r3) + stw r6,4(r3) + addi r3,r3,8 + +12: bf cr7*4+1,13f + lwz r0,0(r4) + addi r4,r4,4 + stw r0,0(r3) + addi r3,r3,4 + +13: bf cr7*4+2,14f + lhz r0,0(r4) + addi r4,r4,2 + sth r0,0(r3) + addi r3,r3,2 + +14: bf cr7*4+3,15f + lbz r0,0(r4) + stb r0,0(r3) + +15: addi r1,r1,STACKFRAMESIZE + ld r3,48(r1) + b .exit_vmx_copy /* tail call optimise */ +#endif /* CONFiG_ALTIVEC */