powerpc: POWER7 optimised memcpy using VMX and enhanced prefetch

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 a66086b819 (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 <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This commit is contained in:
Anton Blanchard 2012-05-30 20:22:09 +00:00 committed by Benjamin Herrenschmidt
parent bce4b4bd91
commit b3f271e86e
3 changed files with 656 additions and 1 deletions

View File

@ -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

View File

@ -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

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@ -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 <anton@au.ibm.com>
*/
#include <asm/ppc_asm.h>
#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 */