Not much. It's common in some Muslim countries, but then in most of those countries minority religious groups such as Druze and Christians also practice it.
Meanwhile, there are many Muslim countries where the practice is unknown.
Personally I prefer the old Spanish method of cleansing the family's honor: track down and kill the rapist or seducer.
Those Methodists are at it again. But seriously folks, which Christian groups in particular practice honor killings?