33 lines
1007 B
Diff
33 lines
1007 B
Diff
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From 9bbffed83b93f633b272368fc536a4f24e9942e6 Mon Sep 17 00:00:00 2001
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From: Yang Yanchao <yangyanchao6@huawei.com>
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Date: Mon, 21 Feb 2022 14:25:25 +0800
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Subject: [PATCH] strcmp: delete align for loop_aligned
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In Kunpeng-920, the performance of strcmp deteriorates only
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when the 16 to 23 characters are different.Or the string is
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only 16-23 characters.That shows 2 misses per iteration which
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means this is a branch predictor issue indeed.
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In the preceding scenario, strcmp performance is 300% worse than expected.
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Fortunately, this problem can be solved by modifying the alignment of the functions.
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---
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sysdeps/aarch64/strcmp.S | 2 --
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1 file changed, 2 deletions(-)
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diff --git a/sysdeps/aarch64/strcmp.S b/sysdeps/aarch64/strcmp.S
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index f225d718..7a048b66 100644
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--- a/sysdeps/aarch64/strcmp.S
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+++ b/sysdeps/aarch64/strcmp.S
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@@ -71,8 +71,6 @@ ENTRY(strcmp)
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b.ne L(misaligned8)
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cbnz tmp, L(mutual_align)
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- .p2align 4
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-
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L(loop_aligned):
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ldr data2, [src1, off2]
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ldr data1, [src1], 8
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--
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2.33.0
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