I tried to hunt down the purpose of the HZ environment variable and why it was set to "100." I finally stumbled upon this entry in /etc/login.defs: ENV_HZ HZ=100. That gave me another search option, but all I found were man pages for login.defs, no explanation of just what HZ=100 or why HZ=1024 for Linux/Alpha. My default search keywords include +2011, since I'm usually looking for info on current versions, not decades-old history. Dropping that restriction led me to a 1992 version of getdef.c, also a 2005 bug discussion for debian in which someone said it was obsoleted by PAM, someone else said it was a relic of the ftape days and if anyone found a program that still uses it they should file a bug.

Long-winded preface aside, may I humbly suggest we just comment out that ENV_HZ line? If we decide the parameter has some historic value, it might be a smart idea to add an explanation of why it is there among the comments. Or, perhaps just delete that section in a future release? Or just ignore this enigma, since it doesn't have any effect whether it is defined or not.

See and scroll down until you find it.