[Intel-gfx] [RFC 00/22] Gen7 batch buffer command parser

[Daniel Vetter]

On Wed, Dec 4, 2013 at 9:13 AM, Daniel Vetter <daniel at ffwll.ch> wrote:
>> Ok, I'll look at the hw context code for buffer mgmt. For "purgeable", just via the
>> madv field in the i915 gem object?
>
> Yeah, though I'd extract two tiny helpers (maybe shared with the madvise
> ioctl) to set an object to purgeable and then resurrect it. The later can
> obviously fail. The helpers are just so we have a place to throw debug
> asserts into, maybe there are other needs for in-kernel caches.

Since we've had tons of fun in the past few months with low memory
handling I think an evil testcase to exercise this cache purging logic
a bit would be good. Quick idea would be to submit dummy batches that
double in size every time (to ensure we have a miss in the cache),
with the last batch careful sized so that the userspace batch plus the
kernel copy will still fit, but not together with all the older cached
batches.

I expect that our other memory thrashing tests will also exercise the
cache purging, but having a specific test which doesn't exercise
anything else really helps to separate issues.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch