[Intel-gfx] freedesktop bug id: 100548, bisected to sched/clock commit

[Thomas Gleixner]

On Thu, 13 Apr 2017, Peter Zijlstra wrote:
> On Thu, Apr 13, 2017 at 03:30:25PM +0300, Martin Peres wrote:
> > On 13/04/17 14:48, Peter Zijlstra wrote:
> > > On Wed, Apr 12, 2017 at 05:49:53PM +0300, Martin Peres wrote:
> > > 
> > > > Good to know. Is there a way to disable this behaviour, as a workaround for
> > > > our CI system until a proper fix lands? We already pushed locally the revert
> > > > for this patch, but that may affect other platforms which do not exhibit the
> > > > problem.
> > > 
> > > Blergh, so the patch is correct, but the __gtod_offset calculation is
> > > fed with absolute crap numbers due to 'circumstances' and then using it
> > > ends up being worse than not using it.
> > 
> > Thanks for taking this bug seriously!
> 
> So I've not actually dug out a Core2 machine, so have only tested this
> by poking random values into the TSC MSR on an otherwise 'good' machine.
> 
> Could you give it a go to see if it works for you?
> 
> Thomas, how much hate?

Well you know, how much I love TSC and its completely non-sensical
behaviour. If that's necessary to cure it, go for it.

Thanks,

	tglx