From the article:
List available entropy
If you are not sure, whether you need haveged, run:
cat /proc/sys/kernel/random/entropy_avail
This command shows you how much entropy your server has collected. If it is rather low (<1000), you should probably install haveged. Otherwise cryptographic applications will block until there is enough entropy available, which eg. could result in slow wlan speed, if your server is a Software access point.