grep with --extended-regexp much slower on Ubuntu 16.04

[Ralf Mardorf]

On Fri, 9 Feb 2018 16:23:42 -0600, C de-Avillez wrote:
>Perhaps (in fact, probably) related to bug 26193 on grep? Please see
>the thread on this at [1]. The fix was included in grep 3.1.
>[1] https://lists.gnu.org/archive/html/bug-grep/2017-03/msg00009.html

Hi,

probably, but actually I didn't read it, at least any guess regarding
page-table islation likely is nonsense, maybe not only because the
booted kernel 4.14.15-rt13-1-rt-securityink might not include the patch
set [2], I confused 4.15 with 4.14.15.
                     ^^^       ^^^^^^         

[2]
On Fri, 9 Feb 2018 19:52:41 +0100, Ralf Mardorf wrote:
>LABEL Securityink_nopti
>    MENU LABEL Arch Linux Rt Securityink nopt^i
>    LINUX ../vmlinuz-linux-rt-securityink
>    APPEND root=LABEL=archlinux ro nopti
>    INITRD ../intel-ucode.img,../initramfs-linux-rt-securityink.img

Now commented out in my bootloader's config:

# "KPTI was merged into Linux kernel version 4.15,[snip] and backported to Linux kernels 4.14.11, 4.9.75, 4.4.110."
# - https://en.wikipedia.org/wiki/Kernel_page-table_isolation
#LABEL Securityink_nopti
#    MENU LABEL Arch Linux Rt Securityink nopt^i
#    LINUX ../vmlinuz-linux-rt-securityink
#    APPEND root=LABEL=archlinux ro nopti
#    INITRD ../intel-ucode.img,../initramfs-linux-rt-securityink.img

-- 
$ pacman -Q linux{,-rt-securityink,-rt,-rt-pussytoes,-rt-cornflower}
linux 4.15.2-2
linux-rt-securityink 4.14.18_rt15-1
linux-rt 4.14.12_rt10-1
linux-rt-pussytoes 4.14.8_rt9-2
linux-rt-cornflower 4.11.12_rt16-1