You're probably right about the locale. I'm using cs_CZ.UTF-8. With LC_ALL=C, both variants run faster and the difference is insignificant.
With cs_CZ.UTF-8, on my machine, your test case takes 2.322s with -i and 0.464s without -i. I tested on my Aspell dictionary dump, where the difference is more noticeable: aspell dump master | head -n 100000 >list.txt grep 2.21 with -i: 7.336s grep 2.21 without -i: 0.312s grep 2.16 with -i: 0.372s grep 2.16 without -i: 0.431s With LC_ALL=C, both versions are about as fast. On Mon, Apr 11, 2016 at 7:02 AM, Paul Eggert <egg...@cs.ucla.edu> wrote: > This is following up on: > > http://bugs.gnu.org/22239 > > Could you please supply some specific test cases to illustrate the problem? > I'm not seeing it, but this could be because I'm not using your locale, or > am using machine-generated patterns. I am using master grep in the C locale > on Ubuntu 15.10, with a pattern file generated like this: > > seq -f 'pattern %g' 100000 >list.txt > > and running commands like this in the 'grep' source directory: > > src/grep -F -i -f list.txt $(git ls-files | grep -v gnulib) > > (or the same command without -i).
