[igt-dev] [PATCH i-g-t 2/2] tests/gem_exec_reloc: Calculate softpin offsets from batch size

[Janusz Krzysztofik]

Hi,

On Friday, October 25, 2019 10:47:30 AM CEST Katarzyna Dec wrote:
> On Wed, Oct 23, 2019 at 10:13:02AM +0100, Chris Wilson wrote:
> > Quoting Janusz Krzysztofik (2019-10-23 10:07:52)
> > > From: Janusz Krzysztofik <janusz.krzysztofik at intel.com>
> > > 
> > > The basic-range subtest assumes 4kB minimum batch size.  On future
> > > backends with possibly bigger minimum batch sizes this subtest will
> > > fail as buffer objects may overlap.  To avoid object overlapping,
> > > offsets need to be calculated with actual minimum batch size in mind.
> > > 
> > > Replace hardcoded constants corresponding to the assumed 4kB minimum
> > > batch size with values calculated from a variable supposed to represent
> > > actual batch size.  For now, the variable is still initialized with the
> > > 4kB value, suitable for backends currently supported by IGT.
> > 
> > You could do this entirely within the reloc API, no? By probing whether
> > a 4KiB offset is legal?
> > -Chris
> 
> Chris - you meant - add such checking to library in IGT or move such 
checking
> into kernel code?
> If any of this above - than I am also for making more global adjustments. 
What if other tests
> would reqire such change? Will we be fixing every binary?

If a test uses softpin offsets not aligned to min page size then it will 
require a fix anyway, I believe.  But the question if that check for minimum 
page size should be implemented as an IOCTL or as an ITG library helper only 
is still valid.  I've assumed the latter and I'm already working on it, with 
an initial implementation of an idea already sent to trybot (it has got a 
false positive BAT failure).

Thanks,
Janusz

> 
> Kasia
>