A life sentence usually means life. Most people sentenced to life in Canada don't get out, ever, regardless the point at which they become parole-eligible.
But the reasoning behind this is that someone with no chance of parole, ever, has no incentive to behave in prison. Someone with even a faint-hope at release is much less dangerous to prison staff. Also, in Canada we have something called "Dangerous Offender status". Once a person is deemed "dangerous", we keep them in jail forever, even if they were only facing a sentence of a couple of years for the offence that brought them to trial.
Me? I'd save all the paperwork and just shoot anyone who'd stab their own kids to death, but that's just me.
