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runtime: improve memmove for short moves on ppc64
This improves the performance of memmove for almost all moves <= 16 bytes for the ppc64 assembler, improving linux/ppc64le, linux/ppc64, aix/ppc64. Only the forward moves were changed, the backward moves were left as is. Additional macro defines were added to improve the readability of the asm. Results from power8: name old time/op new time/op delta Memmove/0 5.70ns ± 0% 5.69ns ± 0% -0.18% (p=0.029 n=4+4) Memmove/1 5.54ns ± 0% 5.39ns ± 0% -2.71% (p=0.029 n=4+4) Memmove/2 6.31ns ± 0% 5.55ns ± 0% -12.08% (p=0.029 n=4+4) Memmove/3 7.41ns ± 0% 5.54ns ± 0% -25.24% (p=0.029 n=4+4) Memmove/4 8.41ns ± 0% 5.56ns ± 0% -33.87% (p=0.029 n=4+4) Memmove/5 10.1ns ± 5% 5.5ns ± 0% -45.30% (p=0.029 n=4+4) Memmove/6 10.3ns ± 0% 5.6ns ± 0% -45.92% (p=0.029 n=4+4) Memmove/7 11.4ns ± 0% 5.7ns ± 0% -50.33% (p=0.029 n=4+4) Memmove/8 5.66ns ± 0% 5.54ns ± 0% -2.12% (p=0.029 n=4+4) Memmove/9 5.66ns ± 0% 6.47ns ± 0% +14.31% (p=0.029 n=4+4) Memmove/10 6.67ns ± 0% 6.22ns ± 0% -6.82% (p=0.029 n=4+4) Memmove/11 7.83ns ± 0% 6.45ns ± 0% -17.60% (p=0.029 n=4+4) Memmove/12 8.91ns ± 0% 6.25ns ± 0% -29.85% (p=0.029 n=4+4) Memmove/13 9.81ns ± 0% 6.48ns ± 0% -33.94% (p=0.029 n=4+4) Memmove/14 10.7ns ± 1% 6.4ns ± 0% -40.00% (p=0.029 n=4+4) Memmove/15 11.8ns ± 0% 6.7ns ± 0% -42.84% (p=0.029 n=4+4) Memmove/16 5.63ns ± 0% 5.56ns ± 0% -1.20% (p=0.029 n=4+4) Change-Id: I2de434f543c5a017395e0850fb9b9f7219583bbb Reviewed-on: https://go-review.googlesource.com/c/go/+/223317 Run-TryBot: Lynn Boger <laboger@linux.vnet.ibm.com> Reviewed-by: Carlos Eduardo Seo <cseo@linux.vnet.ibm.com>
This commit is contained in:
Lynn Boger
parent
f9f57c4443
commit
cbd421f75b
@ -9,78 +9,112 @@
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// See memmove Go doc for important implementation constraints.
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// func memmove(to, from unsafe.Pointer, n uintptr)
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// target address
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#define TGT R3
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// source address
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#define SRC R4
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// length to move
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#define LEN R5
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// number of doublewords
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#define DWORDS R6
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// number of bytes < 8
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#define BYTES R7
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// const 16 used as index
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#define IDX16 R8
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// temp used for copies, etc.
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#define TMP R9
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// number of 32 byte chunks
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#define QWORDS R10
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TEXT runtime·memmove(SB), NOSPLIT|NOFRAME, $0-24
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MOVD to+0(FP), R3
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MOVD from+8(FP), R4
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MOVD n+16(FP), R5
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MOVD to+0(FP), TGT
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MOVD from+8(FP), SRC
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MOVD n+16(FP), LEN
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// Determine if there are doublewords to
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// copy so a more efficient move can be done
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check:
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ANDCC $7, R5, R7 // R7: bytes to copy
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SRD $3, R5, R6 // R6: double words to copy
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CMP R6, $0, CR1 // CR1[EQ] set if no double words to copy
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ANDCC $7, LEN, BYTES // R7: bytes to copy
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SRD $3, LEN, DWORDS // R6: double words to copy
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MOVFL CR0, CR3 // save CR from ANDCC
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CMP DWORDS, $0, CR1 // CR1[EQ] set if no double words to copy
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// Determine overlap by subtracting dest - src and comparing against the
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// length. The catches the cases where src and dest are in different types
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// length. This catches the cases where src and dest are in different types
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// of storage such as stack and static to avoid doing backward move when not
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// necessary.
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SUB R4, R3, R8 // dest - src
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CMPU R8, R5, CR2 // < len?
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SUB SRC, TGT, TMP // dest - src
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CMPU TMP, LEN, CR2 // < len?
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BC 12, 8, backward // BLT CR2 backward
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// Copying forward if no overlap.
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BC 12, 6, noforwardlarge // "BEQ CR1, noforwardlarge"
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SRDCC $2,R6,R8 // 32 byte chunks?
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BNE forward32setup //
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MOVD R6,CTR // R6 = number of double words
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// Move double words
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forward8:
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MOVD 0(R4), R8 // double word
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ADD $8,R4
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MOVD R8, 0(R3) //
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ADD $8,R3
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BC 16, 0, forward8
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BR noforwardlarge // handle remainder
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BC 12, 6, checkbytes // BEQ CR1, checkbytes
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SRDCC $2, DWORDS, QWORDS // 32 byte chunks?
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BEQ lt32gt8 // < 32 bytes
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// Prepare for moves of 32 bytes at a time.
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forward32setup:
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DCBTST (R3) // prepare data cache
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DCBT (R4)
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MOVD R8, CTR // double work count
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MOVD $16, R8
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DCBTST (TGT) // prepare data cache
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DCBT (SRC)
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MOVD QWORDS, CTR // Number of 32 byte chunks
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MOVD $16, IDX16 // 16 for index
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forward32:
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LXVD2X (R4+R0), VS32 // load 16 bytes
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LXVD2X (R4+R8), VS33
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ADD $32, R4
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STXVD2X VS32, (R3+R0) // store 16 bytes
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STXVD2X VS33, (R3+R8)
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ADD $32,R3 // bump up for next set
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LXVD2X (R0)(SRC), VS32 // load 16 bytes
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LXVD2X (IDX16)(SRC), VS33 // load 16 bytes
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ADD $32, SRC
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STXVD2X VS32, (R0)(TGT) // store 16 bytes
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STXVD2X VS33, (IDX16)(TGT)
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ADD $32,TGT // bump up for next set
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BC 16, 0, forward32 // continue
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RLDCLCC $61,R5,$3,R6 // remaining doublewords
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BEQ noforwardlarge
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MOVD R6,CTR // set up the CTR
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BR forward8
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ANDCC $3, DWORDS // remaining doublewords
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BEQ checkbytes // only bytes remain
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noforwardlarge:
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CMP R7,$0 // any remaining bytes
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BC 4, 1, LR // ble lr
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lt32gt8:
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// At this point >= 8 and < 32
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// Move 16 bytes if possible
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CMP DWORDS, $2
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BLT lt16
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LXVD2X (R0)(SRC), VS32
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ADD $-2, DWORDS
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STXVD2X VS32, (R0)(TGT)
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ADD $16, SRC
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ADD $16, TGT
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forwardtail:
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MOVD R7, CTR // move tail bytes
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forwardtailloop:
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MOVBZ 0(R4), R8 // move single bytes
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ADD $1,R4
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MOVBZ R8, 0(R3)
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ADD $1,R3
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BC 16, 0, forwardtailloop
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lt16: // Move 8 bytes if possible
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CMP DWORDS, $1
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BLT checkbytes
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MOVD 0(SRC), TMP
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ADD $8, SRC
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MOVD TMP, 0(TGT)
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ADD $8, TGT
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checkbytes:
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BC 12, 14, LR // BEQ lr
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lt8: // Move word if possible
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CMP BYTES, $4
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BLT lt4
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MOVWZ 0(SRC), TMP
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ADD $-4, BYTES
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MOVW TMP, 0(TGT)
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ADD $4, SRC
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ADD $4, TGT
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lt4: // Move halfword if possible
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CMP BYTES, $2
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BLT lt2
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MOVHZ 0(SRC), TMP
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ADD $-2, BYTES
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MOVH TMP, 0(TGT)
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ADD $2, SRC
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ADD $2, TGT
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lt2: // Move last byte if 1 left
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CMP BYTES, $1
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BC 12, 0, LR // ble lr
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MOVBZ 0(SRC), TMP
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MOVBZ TMP, 0(TGT)
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RET
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backward:
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@ -88,51 +122,51 @@ backward:
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// R3 and R4 are advanced to the end of the destination/source buffers
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// respectively and moved back as we copy.
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ADD R5, R4, R4 // end of source
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ADD R3, R5, R3 // end of dest
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ADD LEN, SRC, SRC // end of source
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ADD TGT, LEN, TGT // end of dest
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BEQ nobackwardtail // earlier condition
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MOVD R7, CTR // bytes to move
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MOVD BYTES, CTR // bytes to move
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backwardtailloop:
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MOVBZ -1(R4), R8 // point to last byte
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SUB $1,R4
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MOVBZ R8, -1(R3)
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SUB $1,R3
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MOVBZ -1(SRC), TMP // point to last byte
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SUB $1,SRC
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MOVBZ TMP, -1(TGT)
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SUB $1,TGT
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BC 16, 0, backwardtailloop // bndz
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nobackwardtail:
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BC 4, 5, LR // ble CR1 lr
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backwardlarge:
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MOVD R6, CTR
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SUB R3, R4, R9 // Use vsx if moving
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CMP R9, $32 // at least 32 byte chunks
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MOVD DWORDS, CTR
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SUB TGT, SRC, TMP // Use vsx if moving
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CMP TMP, $32 // at least 32 byte chunks
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BLT backwardlargeloop // and distance >= 32
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SRDCC $2,R6,R8 // 32 byte chunks
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SRDCC $2,DWORDS,QWORDS // 32 byte chunks
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BNE backward32setup
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backwardlargeloop:
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MOVD -8(R4), R8
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SUB $8,R4
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MOVD R8, -8(R3)
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SUB $8,R3
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MOVD -8(SRC), TMP
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SUB $8,SRC
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MOVD TMP, -8(TGT)
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SUB $8,TGT
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BC 16, 0, backwardlargeloop // bndz
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RET
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backward32setup:
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MOVD R8, CTR // set up loop ctr
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MOVD $16, R8 // 32 bytes at at time
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MOVD QWORDS, CTR // set up loop ctr
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MOVD $16, IDX16 // 32 bytes at at time
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backward32loop:
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SUB $32, R4
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SUB $32, R3
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LXVD2X (R4+R0), VS32 // load 16 bytes
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LXVD2X (R4+R8), VS33
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STXVD2X VS32, (R3+R0) // store 16 bytes
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STXVD2X VS33, (R3+R8)
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SUB $32, TGT
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SUB $32, SRC
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LXVD2X (R0)(TGT), VS32 // load 16 bytes
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LXVD2X (IDX16)(TGT), VS33
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STXVD2X VS32, (R0)(SRC) // store 16 bytes
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STXVD2X VS33, (IDX16)(SRC)
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BC 16, 0, backward32loop // bndz
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BC 4, 5, LR // ble CR1 lr
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MOVD R6, CTR
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MOVD DWORDS, CTR
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BR backwardlargeloop
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