Re: [PATCH] s390 (9/9): no timer interrupts in idle.

From: Martin Schwidefsky
Date: Thu Apr 22 2004 - 06:02:25 EST

> well my worry is the API; should it be "turn the timer off" or should it
> "the next tick is THIS many from now". The later allows one to use the hw
> one-shot mode (PC's can do this) where the scheduler timeslice expiry
> up being a timer as well.

The sysctl is /proc/sys/kernel/hz_timer. If it contains a "1" then HZ timer
active in idle, a "0" indicates that the HZ timer is switchted off.
The semantic "the next tick is THIS many <ticks> from now" IHMO doesn't make
any sense. Skipping ticks will have some really bad effects, e.g. if the xtime
isn't up-to-date network packets will get incorrect time stamps, timer events
will be delivered too late, etc.

blue skies,

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