Well, obviously readline() is not retried when signal arrives (EINTR is set)
I think this should not happen:
perlipc safe signals
Consequently, restartable system calls can fail (with $! set to EINTR ) in places where they previously would have succeeded.
The default :perlio layer retries read, write and close as described above; interrupted wait and waitpid calls will always be retried.
Also, this perl5140delta might explain difference between 5.10 vs 5.14
"Safe signals" optimisation
Signal dispatch has been moved from the runloop into control ops. This should give a few percent speed increase, and eliminates nearly all the speed penalty caused by the introduction of "safe signals" in 5.8.0. Signals should still be dispatched within the same statement as they were previously. If this does not happen, or if you find it possible to create uninterruptible loops, this is a bug, and reports are encouraged of how to recreate such issues.