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internal/bytealg: improve performance of IndexByte for ppc64x

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Use addi+lvx instruction fusion and remove register dependencies in
the main loop to improve performance.

benchmark                      old ns/op     new ns/op     delta
BenchmarkIndexByte/10-192      9.86          9.75          -1.12%
BenchmarkIndexByte/32-192      15.6          11.2          -28.21%
BenchmarkIndexByte/4K-192      155           97.6          -37.03%
BenchmarkIndexByte/4M-192      171790        129650        -24.53%
BenchmarkIndexByte/64M-192     6530982       5018424       -23.16%

benchmark                      old MB/s     new MB/s     speedup
BenchmarkIndexByte/10-192      1013.72      1025.76      1.01x
BenchmarkIndexByte/32-192      2049.47      2868.01      1.40x
BenchmarkIndexByte/4K-192      26422.69     41975.67     1.59x
BenchmarkIndexByte/4M-192      24415.17     32350.74     1.33x
BenchmarkIndexByte/64M-192     10275.46     13372.50     1.30x

Change-Id: Iedf17f01f374d58e85dcd6a972209bfcb7eb6063
Reviewed-on: https://go-review.googlesource.com/137415
Run-TryBot: Lynn Boger <laboger@linux.vnet.ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Lynn Boger <laboger@linux.vnet.ibm.com>
This commit is contained in:
Carlos Eduardo Seo 2018-09-21 16:06:32 -03:00 committed by Lynn Boger
parent 5bba505367
commit 23f7554194
1 changed files with 16 additions and 12 deletions
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28
src/internal/bytealg/indexbyte_ppc64x.s
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@ -38,14 +38,14 @@ TEXT strings·IndexByte(SB),NOSPLIT|NOFRAME,$0-32
BR indexbytebody<>(SB)
TEXT indexbytebody<>(SB),NOSPLIT|NOFRAME,$0-0
DCBT (R3) // Prepare cache line.
MOVD R3,R17 // Save base address for calculating the index later.
RLDICR $0,R3,$60,R8 // Align address to doubleword boundary in R8.
RLDIMI $8,R5,$48,R5 // Replicating the byte across the register.
ADD R4,R3,R7 // Last acceptable address in R7.
DCBT (R8) // Prepare cache line.
RLDIMI $16,R5,$32,R5
CMPU R4,$32 // Check if it's a small string (<32 bytes). Those will be processed differently.
CMPU R4,$32 // Check if it's a small string (≤32 bytes). Those will be processed differently.
MOVD $-1,R9
WORD $0x54661EB8 // Calculate padding in R6 (rlwinm r6,r3,3,26,28).
RLDIMI $32,R5,$0,R5
@ -56,7 +56,7 @@ TEXT indexbytebody<>(SB),NOSPLIT|NOFRAME,$0-0
#else
SRD R6,R9,R9 // Same for Big Endian
#endif
BLE small_string // Jump to the small string case if it's <32 bytes.
BLE small_string // Jump to the small string case if it's ≤32 bytes.
// If we are 64-byte aligned, branch to qw_align just to get the auxiliary values
// in V0, V1 and V10, then branch to the preloop.
@ -97,7 +97,7 @@ qw_align:
LVSL (R0+R0),V11
VSLB V11,V10,V10
VSPLTB $7,V1,V1 // Replicate byte across V1
CMPU R4, $64 // If len <= 64, don't use the vectorized loop
CMPU R4, $64 // If len ≤ 64, don't use the vectorized loop
BLE tail
// We will load 4 quardwords per iteration in the loop, so check for
@ -131,7 +131,7 @@ qw_align:
// 64-byte aligned. Prepare for the main loop.
preloop:
CMPU R4,$64
BLE tail // If len <= 64, don't use the vectorized loop
BLE tail // If len ≤ 64, don't use the vectorized loop
// We are now aligned to a 64-byte boundary. We will load 4 quadwords
// per loop iteration. The last doubleword is in R10, so our loop counter
@ -140,30 +140,34 @@ preloop:
SRD $6,R6,R9 // Loop counter in R9
MOVD R9,CTR
ADD $-64,R8,R8 // Adjust index for loop entry
MOVD $16,R11 // Load offsets for the vector loads
MOVD $32,R9
MOVD $48,R7
// Main loop we will load 64 bytes per iteration
loop:
ADD $64,R8,R8 // Fuse addi+lvx for performance
LVX (R8+R0),V2 // Load 4 16-byte vectors
LVX (R11+R8),V3
LVX (R9+R8),V4
LVX (R7+R8),V5
LVX (R8+R11),V3
VCMPEQUB V1,V2,V6 // Look for byte in each vector
VCMPEQUB V1,V3,V7
LVX (R8+R9),V4
LVX (R8+R7),V5
VCMPEQUB V1,V4,V8
VCMPEQUB V1,V5,V9
VOR V6,V7,V11 // Compress the result in a single vector
VOR V8,V9,V12
VOR V11,V12,V11
VCMPEQUBCC V0,V11,V11 // Check for byte
VOR V11,V12,V13
VCMPEQUBCC V0,V13,V14 // Check for byte
BGE CR6,found
ADD $64,R8,R8
BC 16,0,loop // bdnz loop
// Handle the tailing bytes or R4 <= 64
// Handle the tailing bytes or R4 ≤ 64
RLDICL $0,R6,$58,R4
ADD $64,R8,R8
tail:
CMPU R4,$0
BEQ notfound