update to glibc-2.28-251.2.src.rpm

Signed-off-by: Zhao Hang <wb-zh951434@alibaba-inc.com>

glibc-RHEL-15696-106.patch

@@ -0,0 +1,73 @@
+From 911c63a51c690dd1a97dfc587097277029baf00f Mon Sep 17 00:00:00 2001
+From: Noah Goldstein <goldstein.w.n@gmail.com>
+Date: Wed, 27 Apr 2022 15:13:02 -0500
+Subject: [PATCH] sysdeps: Add 'get_fast_jitter' interace in fast-jitter.h
+Content-type: text/plain; charset=UTF-8
+
+'get_fast_jitter' is meant to be used purely for performance
+purposes. In all cases it's used it should be acceptable to get no
+randomness (see default case). An example use case is in setting
+jitter for retries between threads at a lock. There is a
+performance benefit to having jitter, but only if the jitter can
+be generated very quickly and ultimately there is no serious issue
+if no jitter is generated.
+
+The implementation generally uses 'HP_TIMING_NOW' iff it is
+inlined (avoid any potential syscall paths).
+Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
+---
+ sysdeps/generic/fast-jitter.h | 42 +++++++++++++++++++++++++++++++++++
+ 1 file changed, 42 insertions(+)
+ create mode 100644 sysdeps/generic/fast-jitter.h
+
+diff --git a/sysdeps/generic/fast-jitter.h b/sysdeps/generic/fast-jitter.h
+new file mode 100644
+index 00000000..4dd53e34
+--- /dev/null
++++ b/sysdeps/generic/fast-jitter.h
+@@ -0,0 +1,42 @@
++/* Fallback for fast jitter just return 0.
++   Copyright (C) 2019-2022 Free Software Foundation, Inc.
++   This file is part of the GNU C Library.
++
++   The GNU C Library is free software; you can redistribute it and/or
++   modify it under the terms of the GNU Lesser General Public
++   License as published by the Free Software Foundation; either
++   version 2.1 of the License, or (at your option) any later version.
++
++   The GNU C Library is distributed in the hope that it will be useful,
++   but WITHOUT ANY WARRANTY; without even the implied warranty of
++   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
++   Lesser General Public License for more details.
++
++   You should have received a copy of the GNU Lesser General Public
++   License along with the GNU C Library; if not, see
++   <https://www.gnu.org/licenses/>.  */
++
++#ifndef _FAST_JITTER_H
++# define _FAST_JITTER_H
++
++# include <stdint.h>
++# include <hp-timing.h>
++
++/* Baseline just return 0.  We could create jitter using a clock or
++   'random_bits' but that may imply a syscall and the goal of
++   'get_fast_jitter' is minimal overhead "randomness" when such
++   randomness helps performance.  Adding high overhead the function
++   defeats the purpose.  */
++static inline uint32_t
++get_fast_jitter (void)
++{
++# if HP_TIMING_INLINE
++  hp_timing_t jitter;
++  HP_TIMING_NOW (jitter);
++  return (uint32_t) jitter;
++# else
++  return 0;
++# endif
++}
++
++#endif
+-- 
+GitLab
+