From c6f56985ade937ab4221b8b470139a0ebc4a1825 Mon Sep 17 00:00:00 2001
From: Joel Sing <joel@sing.id.au>
Date: Thu, 27 Jun 2024 20:02:38 +1000
Subject: [PATCH] math/big: implement addVW in riscv64 assembly
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This provides an assembly implementation of addVW for riscv64,
processing up to four words per loop, resulting in a significant
performance gain.
On a StarFive VisionFive 2:
│ addvw.1 │ addvw.2 │
│ sec/op │ sec/op vs base │
AddVW/1-4 57.43n ± 0% 41.45n ± 0% -27.83% (p=0.000 n=10)
AddVW/2-4 69.31n ± 0% 48.15n ± 0% -30.53% (p=0.000 n=10)
AddVW/3-4 76.12n ± 0% 54.97n ± 0% -27.79% (p=0.000 n=10)
AddVW/4-4 85.47n ± 0% 56.14n ± 0% -34.32% (p=0.000 n=10)
AddVW/5-4 96.16n ± 0% 62.82n ± 0% -34.67% (p=0.000 n=10)
AddVW/10-4 149.60n ± 0% 89.55n ± 0% -40.14% (p=0.000 n=10)
AddVW/100-4 1115.0n ± 0% 549.3n ± 0% -50.74% (p=0.000 n=10)
AddVW/1000-4 10.732µ ± 0% 5.060µ ± 0% -52.85% (p=0.000 n=10)
AddVW/10000-4 151.7µ ± 0% 103.7µ ± 0% -31.63% (p=0.000 n=10)
AddVW/100000-4 1.523m ± 0% 1.050m ± 0% -31.03% (p=0.000 n=10)
AddVWext/1-4 57.42n ± 0% 41.45n ± 0% -27.81% (p=0.000 n=10)
AddVWext/2-4 69.32n ± 0% 48.15n ± 0% -30.54% (p=0.000 n=10)
AddVWext/3-4 76.12n ± 0% 54.87n ± 0% -27.92% (p=0.000 n=10)
AddVWext/4-4 85.47n ± 0% 56.14n ± 0% -34.32% (p=0.000 n=10)
AddVWext/5-4 96.15n ± 0% 62.82n ± 0% -34.66% (p=0.000 n=10)
AddVWext/10-4 149.60n ± 0% 89.55n ± 0% -40.14% (p=0.000 n=10)
AddVWext/100-4 1115.0n ± 0% 549.3n ± 0% -50.74% (p=0.000 n=10)
AddVWext/1000-4 10.732µ ± 0% 5.060µ ± 0% -52.85% (p=0.000 n=10)
AddVWext/10000-4 150.5µ ± 0% 103.7µ ± 0% -31.10% (p=0.000 n=10)
AddVWext/100000-4 1.530m ± 0% 1.049m ± 0% -31.41% (p=0.000 n=10)
geomean 1.003µ 633.9n -36.79%
│ addvw.1 │ addvw.2 │
│ B/s │ B/s vs base │
AddVW/1-4 132.8Mi ± 0% 184.1Mi ± 0% +38.55% (p=0.000 n=10)
AddVW/2-4 220.1Mi ± 0% 316.9Mi ± 0% +43.96% (p=0.000 n=10)
AddVW/3-4 300.7Mi ± 0% 416.4Mi ± 0% +38.48% (p=0.000 n=10)
AddVW/4-4 357.1Mi ± 0% 543.6Mi ± 0% +52.25% (p=0.000 n=10)
AddVW/5-4 396.7Mi ± 0% 607.2Mi ± 0% +53.06% (p=0.000 n=10)
AddVW/10-4 510.1Mi ± 0% 852.0Mi ± 0% +67.02% (p=0.000 n=10)
AddVW/100-4 684.1Mi ± 0% 1389.0Mi ± 0% +103.03% (p=0.000 n=10)
AddVW/1000-4 710.9Mi ± 0% 1507.8Mi ± 0% +112.08% (p=0.000 n=10)
AddVW/10000-4 503.1Mi ± 0% 735.8Mi ± 0% +46.26% (p=0.000 n=10)
AddVW/100000-4 501.0Mi ± 0% 726.5Mi ± 0% +45.00% (p=0.000 n=10)
AddVWext/1-4 132.9Mi ± 0% 184.1Mi ± 0% +38.55% (p=0.000 n=10)
AddVWext/2-4 220.1Mi ± 0% 316.9Mi ± 0% +43.98% (p=0.000 n=10)
AddVWext/3-4 300.7Mi ± 0% 417.1Mi ± 0% +38.73% (p=0.000 n=10)
AddVWext/4-4 357.1Mi ± 0% 543.6Mi ± 0% +52.25% (p=0.000 n=10)
AddVWext/5-4 396.7Mi ± 0% 607.2Mi ± 0% +53.05% (p=0.000 n=10)
AddVWext/10-4 510.1Mi ± 0% 852.0Mi ± 0% +67.02% (p=0.000 n=10)
AddVWext/100-4 684.2Mi ± 0% 1389.0Mi ± 0% +103.02% (p=0.000 n=10)
AddVWext/1000-4 710.9Mi ± 0% 1507.7Mi ± 0% +112.08% (p=0.000 n=10)
AddVWext/10000-4 506.9Mi ± 0% 735.8Mi ± 0% +45.15% (p=0.000 n=10)
AddVWext/100000-4 498.6Mi ± 0% 727.0Mi ± 0% +45.79% (p=0.000 n=10)
geomean 388.3Mi 614.3Mi +58.19%
Change-Id: Ib14a4b8c1d81e710753bbf6dd5546bbca44fe3f1
Reviewed-on: https://go-review.googlesource.com/c/go/+/595397
Reviewed-by: Meng Zhuo <mengzhuo1203@gmail.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Mark Ryan <markdryan@rivosinc.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
---
src/math/big/arith_riscv64.s | 59 +++++++++++++++++++++++++++++++++++-
1 file changed, 58 insertions(+), 1 deletion(-)
diff --git a/src/math/big/arith_riscv64.s b/src/math/big/arith_riscv64.s
index 897d08229ee..0029a5b6b44 100644
--- a/src/math/big/arith_riscv64.s
+++ b/src/math/big/arith_riscv64.s
@@ -174,7 +174,64 @@ done:
RET
TEXT ·addVW(SB),NOSPLIT,$0
- JMP ·addVW_g(SB)
+ MOV x+24(FP), X5
+ MOV y+48(FP), X6
+ MOV z+0(FP), X7
+ MOV z_len+8(FP), X30
+
+ MOV $4, X28
+ MOV X6, X29 // c = y
+
+ BEQZ X30, done
+ BLTU X30, X28, loop1
+
+loop4:
+ MOV 0(X5), X8 // x[0]
+ MOV 8(X5), X11 // x[1]
+ MOV 16(X5), X14 // x[2]
+ MOV 24(X5), X17 // x[3]
+
+ ADD X8, X29, X10 // z[0] = x[0] + c
+ SLTU X8, X10, X29 // next c
+
+ ADD X11, X29, X13 // z[1] = x[1] + c
+ SLTU X11, X13, X29 // next c
+
+ ADD X14, X29, X16 // z[2] = x[2] + c
+ SLTU X14, X16, X29 // next c
+
+ ADD X17, X29, X19 // z[3] = x[3] + c
+ SLTU X17, X19, X29 // next c
+
+ MOV X10, 0(X7) // z[0]
+ MOV X13, 8(X7) // z[1]
+ MOV X16, 16(X7) // z[2]
+ MOV X19, 24(X7) // z[3]
+
+ ADD $32, X5
+ ADD $32, X7
+ SUB $4, X30
+
+ BGEU X30, X28, loop4
+ BEQZ X30, done
+
+loop1:
+ MOV 0(X5), X10 // x
+
+ ADD X10, X29, X12 // z = x + c
+ SLTU X10, X12, X29 // next c
+
+ MOV X12, 0(X7) // z
+
+ ADD $8, X5
+ ADD $8, X7
+ SUB $1, X30
+
+ BNEZ X30, loop1
+
+done:
+ MOV X29, c+56(FP) // return c
+ RET
TEXT ·subVW(SB),NOSPLIT,$0
JMP ·subVW_g(SB)
--
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