Before the patch: $ seq 30000000 > in $ for i in `seq 5`; do LC_ALL=C time grep -i foo in; done Command exited with non-zero status 1 0.64user 0.34system 0:00.98elapsed 99%CPU (0avgtext+0avgdata 2352maxresident)k 0inputs+0outputs (0major+179minor)pagefaults 0swaps Command exited with non-zero status 1 0.70user 0.25system 0:00.96elapsed 98%CPU (0avgtext+0avgdata 2352maxresident)k 0inputs+0outputs (0major+179minor)pagefaults 0swaps Command exited with non-zero status 1 0.66user 0.32system 0:01.00elapsed 99%CPU (0avgtext+0avgdata 2368maxresident)k 0inputs+0outputs (0major+180minor)pagefaults 0swaps Command exited with non-zero status 1 0.66user 0.34system 0:01.05elapsed 95%CPU (0avgtext+0avgdata 2368maxresident)k 0inputs+0outputs (0major+180minor)pagefaults 0swaps Command exited with non-zero status 1 0.59user 0.33system 0:00.94elapsed 98%CPU (0avgtext+0avgdata 2368maxresident)k 0inputs+0outputs (0major+180minor)pagefaults 0swaps $ for i in `seq 5`; do LC_ALL=C time grep -iF foo in; done Command exited with non-zero status 1 0.33user 0.23system 0:00.57elapsed 97%CPU (0avgtext+0avgdata 2048maxresident)k 0inputs+0outputs (0major+160minor)pagefaults 0swaps Command exited with non-zero status 1 0.28user 0.21system 0:00.50elapsed 99%CPU (0avgtext+0avgdata 2064maxresident)k 0inputs+0outputs (0major+161minor)pagefaults 0swaps Command exited with non-zero status 1 0.31user 0.20system 0:00.53elapsed 97%CPU (0avgtext+0avgdata 2064maxresident)k 0inputs+0outputs (0major+161minor)pagefaults 0swaps Command exited with non-zero status 1 0.29user 0.21system 0:00.50elapsed 100%CPU (0avgtext+0avgdata 2048maxresident)k 0inputs+0outputs (0major+160minor)pagefaults 0swaps Command exited with non-zero status 1 0.32user 0.17system 0:00.50elapsed 99%CPU (0avgtext+0avgdata 2080maxresident)k 0inputs+0outputs (0major+162minor)pagefaults 0swaps $ for i in `seq 5`; do LC_ALL=C time grep -iP foo in; done Command exited with non-zero status 1 1.58user 0.75system 0:02.44elapsed 95%CPU (0avgtext+0avgdata 2176maxresident)k 0inputs+0outputs (1major+167minor)pagefaults 0swaps Command exited with non-zero status 1 1.70user 0.57system 0:02.33elapsed 97%CPU (0avgtext+0avgdata 2160maxresident)k 0inputs+0outputs (0major+167minor)pagefaults 0swaps Command exited with non-zero status 1 1.73user 0.52system 0:02.33elapsed 96%CPU (0avgtext+0avgdata 2176maxresident)k 0inputs+0outputs (0major+168minor)pagefaults 0swaps Command exited with non-zero status 1 1.60user 0.63system 0:02.28elapsed 97%CPU (0avgtext+0avgdata 2160maxresident)k 0inputs+0outputs (0major+167minor)pagefaults 0swaps Command exited with non-zero status 1 1.79user 0.48system 0:02.34elapsed 97%CPU (0avgtext+0avgdata 2160maxresident)k 0inputs+0outputs (0major+167minor)pagefaults 0swaps $ yes jjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjj | head -10000000 > k $ for i in `seq 5`; do LANG=en_US.UTF-8 time src/grep -i foobar k; done Command exited with non-zero status 1 0.81user 0.44system 0:01.29elapsed 97%CPU (0avgtext+0avgdata 3056maxresident)k 0inputs+0outputs (0major+215minor)pagefaults 0swaps Command exited with non-zero status 1 0.89user 0.35system 0:01.27elapsed 98%CPU (0avgtext+0avgdata 3040maxresident)k 0inputs+0outputs (0major+214minor)pagefaults 0swaps Command exited with non-zero status 1 0.82user 0.37system 0:01.22elapsed 98%CPU (0avgtext+0avgdata 3024maxresident)k 0inputs+0outputs (0major+213minor)pagefaults 0swaps Command exited with non-zero status 1 0.87user 0.31system 0:01.23elapsed 96%CPU (0avgtext+0avgdata 3040maxresident)k 0inputs+0outputs (0major+214minor)pagefaults 0swaps Command exited with non-zero status 1 0.77user 0.46system 0:01.27elapsed 97%CPU (0avgtext+0avgdata 3040maxresident)k 0inputs+0outputs (0major+214minor)pagefaults 0swaps After the patch: $ seq 30000000 > in $ for i in `seq 5`; do LC_ALL=C time grep -i foo in; done Command exited with non-zero status 1 0.69user 0.29system 0:01.00elapsed 98%CPU (0avgtext+0avgdata 2368maxresident)k 0inputs+0outputs (0major+180minor)pagefaults 0swaps Command exited with non-zero status 1 0.69user 0.23system 0:00.94elapsed 98%CPU (0avgtext+0avgdata 2352maxresident)k 0inputs+0outputs (0major+179minor)pagefaults 0swaps Command exited with non-zero status 1 0.72user 0.24system 0:00.96elapsed 100%CPU (0avgtext+0avgdata 2352maxresident)k 0inputs+0outputs (0major+179minor)pagefaults 0swaps Command exited with non-zero status 1 0.63user 0.26system 0:00.90elapsed 98%CPU (0avgtext+0avgdata 2368maxresident)k 0inputs+0outputs (0major+180minor)pagefaults 0swaps Command exited with non-zero status 1 0.58user 0.31system 0:00.92elapsed 97%CPU (0avgtext+0avgdata 2368maxresident)k 0inputs+0outputs (0major+180minor)pagefaults 0swaps $ for i in `seq 5`; do LC_ALL=C time grep -iF foo in; done Command exited with non-zero status 1 0.28user 0.26system 0:00.56elapsed 97%CPU (0avgtext+0avgdata 2048maxresident)k 0inputs+0outputs (0major+174minor)pagefaults 0swaps Command exited with non-zero status 1 0.31user 0.21system 0:00.53elapsed 97%CPU (0avgtext+0avgdata 2064maxresident)k 0inputs+0outputs (0major+161minor)pagefaults 0swaps Command exited with non-zero status 1 0.31user 0.18system 0:00.50elapsed 98%CPU (0avgtext+0avgdata 2048maxresident)k 0inputs+0outputs (0major+160minor)pagefaults 0swaps Command exited with non-zero status 1 0.32user 0.19system 0:00.54elapsed 96%CPU (0avgtext+0avgdata 2064maxresident)k 0inputs+0outputs (0major+161minor)pagefaults 0swaps Command exited with non-zero status 1 0.29user 0.20system 0:00.52elapsed 95%CPU (0avgtext+0avgdata 2048maxresident)k 0inputs+0outputs (0major+160minor)pagefaults 0swaps $ for i in `seq 5`; do LC_ALL=C time grep -iP foo in; done Command exited with non-zero status 1 1.78user 0.49system 0:02.33elapsed 97%CPU (0avgtext+0avgdata 2176maxresident)k 0inputs+0outputs (0major+168minor)pagefaults 0swaps Command exited with non-zero status 1 1.79user 0.42system 0:02.26elapsed 97%CPU (0avgtext+0avgdata 2176maxresident)k 0inputs+0outputs (0major+168minor)pagefaults 0swaps Command exited with non-zero status 1 1.76user 0.50system 0:02.31elapsed 97%CPU (0avgtext+0avgdata 2160maxresident)k 0inputs+0outputs (0major+167minor)pagefaults 0swaps Command exited with non-zero status 1 1.75user 0.47system 0:02.28elapsed 97%CPU (0avgtext+0avgdata 2176maxresident)k 0inputs+0outputs (0major+168minor)pagefaults 0swaps Command exited with non-zero status 1 1.82user 0.42system 0:02.30elapsed 97%CPU (0avgtext+0avgdata 2160maxresident)k 0inputs+0outputs (0major+167minor)pagefaults 0swaps $ for i in `seq 5`; do LANG=en_US.UTF-8 time src/grep -i foobar k; done Command exited with non-zero status 1 0.85user 0.42system 0:01.36elapsed 93%CPU (0avgtext+0avgdata 3024maxresident)k 0inputs+0outputs (0major+227minor)pagefaults 0swaps Command exited with non-zero status 1 0.79user 0.42system 0:01.25elapsed 97%CPU (0avgtext+0avgdata 3040maxresident)k 0inputs+0outputs (0major+228minor)pagefaults 0swaps Command exited with non-zero status 1 0.88user 0.30system 0:01.20elapsed 99%CPU (0avgtext+0avgdata 3040maxresident)k 0inputs+0outputs (0major+228minor)pagefaults 0swaps Command exited with non-zero status 1 0.69user 0.51system 0:01.23elapsed 97%CPU (0avgtext+0avgdata 3040maxresident)k 0inputs+0outputs (0major+214minor)pagefaults 0swaps Command exited with non-zero status 1 0.68user 0.54system 0:01.25elapsed 98%CPU (0avgtext+0avgdata 3040maxresident)k 0inputs+0outputs (0major+214minor)pagefaults 0swaps After the patch + removal of trivial_case_ignore: $ seq 30000000 > in $ for i in `seq 5`; do LC_ALL=C time grep -i foo in; done Command exited with non-zero status 1 0.68user 1.47system 0:06.08elapsed 35%CPU (0avgtext+0avgdata 2368maxresident)k 0inputs+0outputs (0major+180minor)pagefaults 0swaps Command exited with non-zero status 1 0.84user 0.99system 0:03.50elapsed 52%CPU (0avgtext+0avgdata 2368maxresident)k 0inputs+0outputs (0major+180minor)pagefaults 0swaps Command exited with non-zero status 1 0.72user 0.25system 0:00.99elapsed 97%CPU (0avgtext+0avgdata 2352maxresident)k 0inputs+0outputs (0major+193minor)pagefaults 0swaps Command exited with non-zero status 1 0.67user 0.32system 0:01.03elapsed 96%CPU (0avgtext+0avgdata 2352maxresident)k 0inputs+0outputs (0major+179minor)pagefaults 0swaps Command exited with non-zero status 1 0.63user 0.37system 0:01.05elapsed 96%CPU (0avgtext+0avgdata 2368maxresident)k 0inputs+0outputs (0major+180minor)pagefaults 0swaps $ for i in `seq 5`; do LC_ALL=C time grep -iF foo in; done Command exited with non-zero status 1 0.33user 0.31system 0:00.68elapsed 94%CPU (0avgtext+0avgdata 2064maxresident)k 0inputs+0outputs (0major+161minor)pagefaults 0swaps Command exited with non-zero status 1 0.34user 0.22system 0:00.58elapsed 97%CPU (0avgtext+0avgdata 2080maxresident)k 0inputs+0outputs (0major+162minor)pagefaults 0swaps Command exited with non-zero status 1 0.38user 0.18system 0:00.56elapsed 100%CPU (0avgtext+0avgdata 2048maxresident)k 0inputs+0outputs (0major+160minor)pagefaults 0swaps Command exited with non-zero status 1 0.35user 0.22system 0:00.58elapsed 98%CPU (0avgtext+0avgdata 2048maxresident)k 0inputs+0outputs (0major+160minor)pagefaults 0swaps Command exited with non-zero status 1 0.33user 0.29system 0:00.64elapsed 96%CPU (0avgtext+0avgdata 2064maxresident)k 0inputs+0outputs (0major+176minor)pagefaults 0swaps $ for i in `seq 5`; do LC_ALL=C time grep -iP foo in; done Command exited with non-zero status 1 1.72user 0.67system 0:02.45elapsed 97%CPU (0avgtext+0avgdata 2176maxresident)k 0inputs+0outputs (1major+167minor)pagefaults 0swaps Command exited with non-zero status 1 1.87user 0.55system 0:02.49elapsed 97%CPU (0avgtext+0avgdata 2160maxresident)k 0inputs+0outputs (0major+167minor)pagefaults 0swaps Command exited with non-zero status 1 1.73user 0.55system 0:02.33elapsed 97%CPU (0avgtext+0avgdata 2176maxresident)k 0inputs+0outputs (0major+168minor)pagefaults 0swaps Command exited with non-zero status 1 1.87user 0.44system 0:02.34elapsed 98%CPU (0avgtext+0avgdata 2176maxresident)k 0inputs+0outputs (0major+168minor)pagefaults 0swaps Command exited with non-zero status 1 1.61user 0.69system 0:02.35elapsed 97%CPU (0avgtext+0avgdata 2160maxresident)k 0inputs+0outputs (0major+167minor)pagefaults 0swaps $ for i in `seq 5`; do LANG=en_US.UTF-8 time src/grep -i foobar k; done Command exited with non-zero status 1 0.90user 0.41system 0:01.41elapsed 93%CPU (0avgtext+0avgdata 3008maxresident)k 0inputs+0outputs (0major+212minor)pagefaults 0swaps Command exited with non-zero status 1 0.85user 0.33system 0:01.18elapsed 99%CPU (0avgtext+0avgdata 3024maxresident)k 0inputs+0outputs (0major+213minor)pagefaults 0swaps Command exited with non-zero status 1 0.87user 0.33system 0:01.22elapsed 98%CPU (0avgtext+0avgdata 3008maxresident)k 0inputs+0outputs (0major+227minor)pagefaults 0swaps Command exited with non-zero status 1 0.82user 0.36system 0:01.22elapsed 96%CPU (0avgtext+0avgdata 3008maxresident)k 0inputs+0outputs (0major+212minor)pagefaults 0swaps Command exited with non-zero status 1 0.81user 0.38system 0:01.23elapsed 97%CPU (0avgtext+0avgdata 3008maxresident)k 0inputs+0outputs (0major+212minor)pagefaults 0swaps