Re: [PATCH igt] igt/drv_hangman: Use manual error-state generation

Chris Wilson
2016-10-20T13:23:01Z

On Thu, Oct 20, 2016 at 03:14:30PM +0200, Daniel Vetter wrote:
> On Thu, Oct 20, 2016 at 10:46:01AM +0100, Chris Wilson wrote:
> > On Thu, Oct 20, 2016 at 11:29:05AM +0200, Daniel Vetter wrote:
> > > On Thu, Oct 20, 2016 at 10:07:39AM +0100, Chris Wilson wrote:
> > > > For the basic error state, we only desire that an error state be created
> > > > following a hang. For that purpose, we do not need a real hang (slow
> > > > 6-12s) but can inject one instead (fast <1s).
> > > >
> > > > Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
> > >
> > > Should we instead speed up hangcheck? I think there's lots of value in
> > > making sure not just error dumping, but also hang detection works somewhat
> > > in BAT. Since if it doesn't any attempt at a full run will lead to pretty
> > > serious disasters. And I have this dream that BAT is the gating thing
> > > deciding whether a patch series deserves a complete pre-merge run ;-)
> >
> > We have full-hang detection in BAT elsewhere as well. This particular
> > test was only asking the question "do we generate an error state", hence
> > why I felt it was safe to just do that and skip a simulated hang.
>
> Hm, is it worth it then in BAT? Or does the other test not check whether
> the error capture part was mildly successful? Might be worth it to just
> combine them (in BAT) for even more time saved. Either way ack on this.

No, the other tests are to check we survive a hang, not that we generate
post-mortem error state. This test takes approximately 0.2s on a slow
device (at mild debug levels), and I think is concise enough to keep
separate.
-Chris

--
Chris Wilson, Intel Open Source Technology Centre