!370 strcmp：删除loop_aligned的对齐

From: @yang_yanchao 
Reviewed-by: @liqingqing_1229 
Signed-off-by: @liqingqing_1229

glibc.spec

@@ -66,7 +66,7 @@
 ##############################################################################
 Name: 	 	glibc
 Version: 	2.34
-Release: 	58
+Release: 	59
 Summary: 	The GNU libc libraries
 License:	%{all_license}
 URL: 		http://www.gnu.org/software/glibc/
@@ -205,6 +205,7 @@ Patch9011: delete-check-installed-headers-c-and-check-installed.patch
 Patch9012: fix-CVE-2019-1010023.patch
 Patch9013: fix-tst-glibcsyscalls-due-to-kernel-reserved-some-sy.patch
 Patch9014: use-region-to-instead-of-country-for-extract-timezon.patch
+Patch9015: strcmp-delete-align-for-loop_aligned.patch
 
 Obsoletes: nscd < 2.35
 Provides: ldconfig rtld(GNU_HASH) bundled(gnulib)
@@ -1219,6 +1220,9 @@ fi
 %endif
 
 %changelog
+* Wed Feb 23 2022 Yang Yanchao<yangyanchao6@huawei.com> - 2.34-59
+- strcmp: delete align for loop_aligned
+
 * Wed Feb 23 2022 Yang Yanchao<yangyanchao6@huawei.com> - 2.34-58
 - The release of glibc.src.rpm in OpenEuler is not based on the architecture.
   Developers only have glibc.src.rpm in the ARM, so add all testsuite_whitelist in glibc.src.rpm.

strcmp-delete-align-for-loop_aligned.patch

@@ -0,0 +1,32 @@
+From 9bbffed83b93f633b272368fc536a4f24e9942e6 Mon Sep 17 00:00:00 2001
+From: Yang Yanchao <yangyanchao6@huawei.com>
+Date: Mon, 21 Feb 2022 14:25:25 +0800
+Subject: [PATCH] strcmp: delete align for loop_aligned
+
+In Kunpeng-920, the performance of strcmp deteriorates only
+when the 16 to 23 characters are different.Or the string is
+only 16-23 characters.That shows 2 misses per iteration which
+means this is a branch predictor issue indeed.
+In the preceding scenario, strcmp performance is 300% worse than expected.
+
+Fortunately, this problem can be solved by modifying the alignment of the functions.
+---
+ sysdeps/aarch64/strcmp.S | 2 --
+ 1 file changed, 2 deletions(-)
+
+diff --git a/sysdeps/aarch64/strcmp.S b/sysdeps/aarch64/strcmp.S
+index f225d718..7a048b66 100644
+--- a/sysdeps/aarch64/strcmp.S
++++ b/sysdeps/aarch64/strcmp.S
+@@ -71,8 +71,6 @@ ENTRY(strcmp)
+ 	b.ne	L(misaligned8)
+ 	cbnz	tmp, L(mutual_align)
+ 
+-	.p2align 4
+-
+ L(loop_aligned):
+ 	ldr	data2, [src1, off2]
+ 	ldr	data1, [src1], 8
+-- 
+2.33.0
+