[Mesa-dev] [PATCH 1/7] mesa: Add usage history bitfield to buffer objects

[Marek Olšák]

On Thu, Oct 2, 2014 at 6:05 AM, Ilia Mirkin <imirkin at alum.mit.edu> wrote:
> On Wed, Oct 1, 2014 at 12:06 PM, Marek Olšák <maraeo at gmail.com> wrote:
>> On Wed, Oct 1, 2014 at 11:02 AM, Chris Forbes <chrisf at ijw.co.nz> wrote:
>>> In the drivers, we occasionally want to reallocate the backing
>>> store for a buffer object; often to avoid waiting for the GPU
>>> to be finished with the previous contents.
>>>
>>> At the point that happens, we don't have a good way of determining
>>> where else the buffer object may be bound, and so no good way of
>>> determining which dirty flags need to be raised -- it's fairly
>>> expensive to go looking at all the possible binding points.
>>
>> I don't think so. We do look at all binding points in radeon drivers.
>> See for example r600_invalidate_buffer. It also only flags the binding
>> points where the buffer being invalidated is bound and only those
>> bindings points are updated.
>>
>> Also I don't see a point in adding things to mtypes.h that are only
>> used by one driver.
>
> Without commenting on the approach, Chris's new test does fail on
> nvc0. Perhaps check radeon as well? Could be some sort of driver fail
> there, of course, I didn't spend too much time investigating. I
> figured we'd need the same fix in mesa/st.

It fails because texbufferrange doesn't flag anything, so st/mesa
doesn't know. Replacing FLUSH_VERTICES(ctx, 0) with:

FLUSH_VERTICES(ctx, _NEW_TEXTURE);

fixes it for radeon.

Marek