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

From: Arjan van de Ven
Date: Thu Apr 22 2004 - 06:05:53 EST

On Thu, Apr 22, 2004 at 12:53:15PM +0200, Martin Schwidefsky wrote:
> 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.

why? Most hardware have an alternative time source for such time stamps.
Timer events *won't* be delivered too late, simply *because* the timer said
"don't bother checking back for X amount of time", so when that time has
expired (eg the delay) then the timer comparison tells the kernel "ok this
one is due now".

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