132 lines
3.6 KiB
Diff
132 lines
3.6 KiB
Diff
From 9bc2ed8f46d80859a5596789cc9e8cc2de84b0e7 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 13:39:37 +0100
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Subject: [PATCH] [2/5] AArch64: Improve A64FX memset for large sizes
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Improve performance of large memsets. Simplify alignment code. For zero memset
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use DC ZVA, which almost doubles performance. For non-zero memsets use the
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unroll8 loop which is about 10% faster.
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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 | 85 +++++++-----------------
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1 file changed, 25 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 cf3d402ef6..75cf43ae79 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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@@ -27,14 +27,11 @@
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*/
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#define L1_SIZE (64*1024) // L1 64KB
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-#define L2_SIZE (8*1024*1024) // L2 8MB - 1MB
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+#define L2_SIZE (8*1024*1024) // L2 8MB
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#define CACHE_LINE_SIZE 256
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#define PF_DIST_L1 (CACHE_LINE_SIZE * 16) // Prefetch distance L1
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-#define ZF_DIST (CACHE_LINE_SIZE * 21) // Zerofill distance
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-#define rest x8
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+#define rest x2
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#define vector_length x9
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-#define vl_remainder x10 // vector_length remainder
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-#define cl_remainder x11 // CACHE_LINE_SIZE remainder
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#if HAVE_AARCH64_SVE_ASM
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# if IS_IN (libc)
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@@ -42,14 +39,6 @@
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.arch armv8.2-a+sve
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- .macro dc_zva times
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- dc zva, tmp1
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- add tmp1, tmp1, CACHE_LINE_SIZE
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- .if \times-1
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- dc_zva "(\times-1)"
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- .endif
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- .endm
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-
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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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.if \last-\first
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@@ -188,54 +177,30 @@ L(L1_prefetch): // if rest >= L1_SIZE
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cbnz rest, L(unroll32)
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ret
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-L(L2):
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- // align dst address at vector_length byte boundary
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- sub tmp1, vector_length, 1
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- ands tmp2, dst, tmp1
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- // if vl_remainder == 0
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- b.eq 1f
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- sub vl_remainder, vector_length, tmp2
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- // process remainder until the first vector_length boundary
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- whilelt p2.b, xzr, vl_remainder
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- st1b z0.b, p2, [dst]
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- add dst, dst, vl_remainder
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- sub rest, rest, vl_remainder
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- // align dstin address at CACHE_LINE_SIZE byte boundary
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-1: mov tmp1, CACHE_LINE_SIZE
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- ands tmp2, dst, CACHE_LINE_SIZE - 1
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- // if cl_remainder == 0
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- b.eq L(L2_dc_zva)
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- sub cl_remainder, tmp1, tmp2
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- // process remainder until the first CACHE_LINE_SIZE boundary
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- mov tmp1, xzr // index
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-2: whilelt p2.b, tmp1, cl_remainder
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- st1b z0.b, p2, [dst, tmp1]
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- incb tmp1
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- cmp tmp1, cl_remainder
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- b.lo 2b
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- add dst, dst, cl_remainder
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- sub rest, rest, cl_remainder
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-
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-L(L2_dc_zva):
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- // zero fill
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- mov tmp1, dst
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- dc_zva (ZF_DIST / CACHE_LINE_SIZE) - 1
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- mov zva_len, ZF_DIST
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- add tmp1, zva_len, CACHE_LINE_SIZE * 2
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- // unroll
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+ // count >= L2_SIZE
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.p2align 3
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-1: st1b_unroll 0, 3
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- add tmp2, dst, zva_len
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- dc zva, tmp2
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- st1b_unroll 4, 7
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- add tmp2, tmp2, CACHE_LINE_SIZE
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- dc zva, tmp2
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- add dst, dst, CACHE_LINE_SIZE * 2
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- sub rest, rest, CACHE_LINE_SIZE * 2
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- cmp rest, tmp1 // ZF_DIST + CACHE_LINE_SIZE * 2
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- b.ge 1b
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- cbnz rest, L(unroll8)
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- ret
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+L(L2):
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+ tst valw, 255
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+ b.ne L(unroll8)
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+ // align dst to CACHE_LINE_SIZE byte boundary
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+ and tmp2, dst, CACHE_LINE_SIZE - 1
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+ st1b z0.b, p0, [dst, 0, mul vl]
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+ st1b z0.b, p0, [dst, 1, mul vl]
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+ st1b z0.b, p0, [dst, 2, mul vl]
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+ st1b z0.b, p0, [dst, 3, mul vl]
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+ sub dst, dst, tmp2
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+ add count, count, tmp2
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+
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+ // clear cachelines using DC ZVA
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+ sub count, count, CACHE_LINE_SIZE * 2
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+ .p2align 4
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+1: add dst, dst, CACHE_LINE_SIZE
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+ dc zva, dst
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+ subs count, count, CACHE_LINE_SIZE
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+ b.hi 1b
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+ add count, count, CACHE_LINE_SIZE
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+ add dst, dst, CACHE_LINE_SIZE
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+ b L(last)
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END (MEMSET)
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libc_hidden_builtin_def (MEMSET)
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--
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2.31.1
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