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

[Brian Bird]

I've noticed Ubuntu 16.04LTS seems to run greps with "-extended-regexp" much slower than Ubuntu 14.04LTS. I can reproduce this on the same hardware simply by re-installing with the relevant operating system.

Eg. On Ubuntu 14.04
# openssl rand -out /tmp/random.txt -base64 100000000; time grep --extended-regexp "[0-9]{10}$" /tmp/random.txt
real    0m0.513s
user    0m0.474s
sys     0m0.036s

On Ubuntu 16.04:
# openssl rand -out /tmp/random.txt -base64 100000000; time grep --extended-regexp "[0-9]{10}$" /tmp/random.txt

real    0m20.619s
user    0m20.587s
sys     0m0.028s

Q. Can anyone try the above commands and verify if they have similar problems?
Q. Can anyone suggest anything that might cause this?

Any pointers appreciated!
Thanks