Kernel parameters... X86_TSC

[Thomas Charron]

On 8/15/08, Paul Lussier <p.lussier at comcast.net> wrote:
> Thanks Thom!
> We've also discovered a simple and interesting test to break systems :(
>
> Run this, and at some point, if your clocksources are unstable, your
> system will hang, and eventually crash:
>
>  while true; do sudo hwclock ; sleep 1 ; done
>
> We've run this across 2.6.18, 2.6.2[45] and set the clocksource in
> menu.lst to each of: tsc, hpet, acpi_pm, jiffies.  We can crash them
> all :(

  Wow.  They all crashed?  TSC is unstable on many Intel systems
becouse of hardware clock control, so without the software knowing
whats going on, internal to the processor, the clock changes, and/or
appears to be in two states at the same time.  ACPI is unreliable but
reliable, aka, it may take 3 reads to get a correct reading, which
makes it slower in general.  But it crashes with hpet and jiffies?

  Was it a crash or a hang?

-- 
-- Thomas