From 07f5e6c5e2f91854024c6294e436418c504fe66b Mon Sep 17 00:00:00 2001
From: "H.J. Lu" <hjl.tools@gmail.com>
Date: Sun, 13 Dec 2020 04:56:41 -0800
Subject: [PATCH] x86: Remove the default REP MOVSB threshold tunable value [BZ
#27061]
Since we can't tell if the tunable value is set by user or not:
https://sourceware.org/bugzilla/show_bug.cgi?id=27069
remove the default REP MOVSB threshold tunable value so that the correct
default value will be set correctly by init_cacheinfo ().
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
---
sysdeps/x86/dl-tunables.list | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
@@ -39,9 +39,11 @@ glibc {
# REP MOVSB. Since larger register size can move more data with a
# single load and store, the threshold is higher with larger register
# size. Note: Since the REP MOVSB threshold must be greater than 8
- # times of vector size, the minium value must be updated at run-time.
+ # times of vector size and the default value is 2048 * (vector size
+ # / 16), the default value and the minimum value must be updated at
+ # run-time. NB: Don't set the default value since we can't tell if
+ # the tunable value is set by user or not [BZ #27069].
minval: 1
- default: 2048
}
x86_rep_stosb_threshold {
type: SIZE_T
--
2.29.2