137 lines
3.7 KiB
Diff
137 lines
3.7 KiB
Diff
From 07b427296b8d59f439144029d9a948f6c1ce0a31 Mon Sep 17 00:00:00 2001
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From: Wilco Dijkstra <wdijkstr@arm.com>
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Date: Tue, 10 Aug 2021 13:30:27 +0100
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Subject: [PATCH] [1/5] AArch64: Improve A64FX memset for small sizes
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Improve performance of small memsets by reducing instruction counts and
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improving code alignment. Bench-memset shows 35-45% performance gain for
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small sizes.
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Reviewed-by: Naohiro Tamura <naohirot@fujitsu.com>
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---
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sysdeps/aarch64/multiarch/memset_a64fx.S | 96 +++++++++---------------
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1 file changed, 36 insertions(+), 60 deletions(-)
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diff --git a/sysdeps/aarch64/multiarch/memset_a64fx.S b/sysdeps/aarch64/multiarch/memset_a64fx.S
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index ce54e5418b..cf3d402ef6 100644
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--- a/sysdeps/aarch64/multiarch/memset_a64fx.S
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+++ b/sysdeps/aarch64/multiarch/memset_a64fx.S
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@@ -51,78 +51,54 @@
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.endm
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.macro st1b_unroll first=0, last=7
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- st1b z0.b, p0, [dst, #\first, mul vl]
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+ st1b z0.b, p0, [dst, \first, mul vl]
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.if \last-\first
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st1b_unroll "(\first+1)", \last
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.endif
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.endm
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- .macro shortcut_for_small_size exit
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- // if rest <= vector_length * 2
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- whilelo p0.b, xzr, count
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- whilelo p1.b, vector_length, count
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- b.last 1f
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- st1b z0.b, p0, [dstin, #0, mul vl]
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- st1b z0.b, p1, [dstin, #1, mul vl]
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- ret
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-1: // if rest > vector_length * 8
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- cmp count, vector_length, lsl 3 // vector_length * 8
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- b.hi \exit
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- // if rest <= vector_length * 4
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- lsl tmp1, vector_length, 1 // vector_length * 2
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- whilelo p2.b, tmp1, count
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- incb tmp1
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- whilelo p3.b, tmp1, count
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- b.last 1f
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- st1b z0.b, p0, [dstin, #0, mul vl]
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- st1b z0.b, p1, [dstin, #1, mul vl]
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- st1b z0.b, p2, [dstin, #2, mul vl]
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- st1b z0.b, p3, [dstin, #3, mul vl]
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- ret
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-1: // if rest <= vector_length * 8
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- lsl tmp1, vector_length, 2 // vector_length * 4
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- whilelo p4.b, tmp1, count
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- incb tmp1
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- whilelo p5.b, tmp1, count
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- b.last 1f
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- st1b z0.b, p0, [dstin, #0, mul vl]
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- st1b z0.b, p1, [dstin, #1, mul vl]
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- st1b z0.b, p2, [dstin, #2, mul vl]
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- st1b z0.b, p3, [dstin, #3, mul vl]
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- st1b z0.b, p4, [dstin, #4, mul vl]
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- st1b z0.b, p5, [dstin, #5, mul vl]
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- ret
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-1: lsl tmp1, vector_length, 2 // vector_length * 4
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- incb tmp1 // vector_length * 5
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- incb tmp1 // vector_length * 6
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- whilelo p6.b, tmp1, count
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- incb tmp1
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- whilelo p7.b, tmp1, count
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- st1b z0.b, p0, [dstin, #0, mul vl]
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- st1b z0.b, p1, [dstin, #1, mul vl]
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- st1b z0.b, p2, [dstin, #2, mul vl]
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- st1b z0.b, p3, [dstin, #3, mul vl]
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- st1b z0.b, p4, [dstin, #4, mul vl]
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- st1b z0.b, p5, [dstin, #5, mul vl]
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- st1b z0.b, p6, [dstin, #6, mul vl]
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- st1b z0.b, p7, [dstin, #7, mul vl]
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- ret
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- .endm
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-ENTRY (MEMSET)
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+#undef BTI_C
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+#define BTI_C
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+ENTRY (MEMSET)
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PTR_ARG (0)
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SIZE_ARG (2)
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- cbnz count, 1f
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- ret
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-1: dup z0.b, valw
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cntb vector_length
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- // shortcut for less than vector_length * 8
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- // gives a free ptrue to p0.b for n >= vector_length
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- shortcut_for_small_size L(vl_agnostic)
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- // end of shortcut
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+ dup z0.b, valw
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+ whilelo p0.b, vector_length, count
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+ b.last 1f
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+ whilelo p1.b, xzr, count
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+ st1b z0.b, p1, [dstin, 0, mul vl]
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+ st1b z0.b, p0, [dstin, 1, mul vl]
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+ ret
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+
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+ // count >= vector_length * 2
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+1: cmp count, vector_length, lsl 2
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+ add dstend, dstin, count
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+ b.hi 1f
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+ st1b z0.b, p0, [dstin, 0, mul vl]
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+ st1b z0.b, p0, [dstin, 1, mul vl]
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+ st1b z0.b, p0, [dstend, -2, mul vl]
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+ st1b z0.b, p0, [dstend, -1, mul vl]
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+ ret
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+
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+ // count > vector_length * 4
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+1: lsl tmp1, vector_length, 3
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+ cmp count, tmp1
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+ b.hi L(vl_agnostic)
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+ st1b z0.b, p0, [dstin, 0, mul vl]
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+ st1b z0.b, p0, [dstin, 1, mul vl]
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+ st1b z0.b, p0, [dstin, 2, mul vl]
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+ st1b z0.b, p0, [dstin, 3, mul vl]
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+ st1b z0.b, p0, [dstend, -4, mul vl]
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+ st1b z0.b, p0, [dstend, -3, mul vl]
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+ st1b z0.b, p0, [dstend, -2, mul vl]
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+ st1b z0.b, p0, [dstend, -1, mul vl]
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+ ret
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+ .p2align 4
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L(vl_agnostic): // VL Agnostic
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mov rest, count
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mov dst, dstin
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--
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2.31.1
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