Re: [clocksource] jiffies as clocksource kills box

From: Thomas Gleixner
Date: Wed Jan 16 2008 - 08:56:37 EST


On Tue, 15 Jan 2008, Mike Galbraith wrote:

> Greetings,
>
> Per $subject, echo jiffies > current_clocksource pretty thoroughly kills
> my P4 box, and does so with every kernel I have (2.6.22->present). I
> can drive the box via mouse clicks and poke around, but trying to select
> another clocksource thereafter is nogo.. cat current_clocksource emits
> jiffies, and box remains comatose unless prodded.

I guess your box has high resolution timers and/or dynamic ticks
enabled. In that case we really can not switch to jiffies. We also
have to prevent PIT from being selected.

I have a patch pending for the PIT issue. Will add jiffies to this as
well.

We'll fix that in .25 as it requires root user interaction and does
not show up magically.

Thanks,
tglx
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/