On Wed, Dec 10, 2014 at 04:33:14PM +0000, Dave Gordon wrote: > On 10/12/14 10:58, Daniel Vetter wrote: > > On Tue, Dec 09, 2014 at 12:59:11PM +0000, [email protected] wrote: > >> From: John Harrison <[email protected]> > >> > >> The scheduler decouples the submission of batch buffers to the driver with > >> their > >> submission to the hardware. This basically means splitting the execbuffer() > >> function in half. This change rearranges some code ready for the split to > >> occur. > > > > Now there's the curios question: Where will the split in top/bottom halves > > be? Without that I have no idea whether it makes sense and so can't review > > this patch. At least if the goal is to really prep for the scheduler and > > not just move a few lines around ;-) > > -Daniel > > > [snip] > >> > >> + i915_gem_execbuffer_move_to_active(vmas, ring); > >> + > >> + /* To be split into two functions here... */ > >> + > >> + /* Unconditionally invalidate gpu caches and ensure that we do flush > >> + * any residual writes from the previous batch. > >> + */ > >> + ret = logical_ring_invalidate_all_caches(ringbuf); > > It'll be where the marker comment is above. Ahead of that point is stuff > to do with setting up software state; after that we're talking to h/w. > When the scheduler code goes it, it decouples the two by interposing at > this point. Then batches go into it with s/w state set up, but don't get > to talk to the h/w until they're selected for execution, possibly in a > different order.
Oops, I guess I need see a doctor to check my eyesight ;-) Two comments about code that's still in the bottom half: - There's lots of input validation code still below that cutoff point which needs to be moved above to still be able to return -EINVAL. Test coverage is the critical part here, but I think we've closed most of our gaps. I guess a future patch will address this? - retire_commands and so add_request are also in the cutoff. For shrinker interactions to work seamlessly we need to have both the objects on the active list and the request in the lists. So I expect more untangling there to separate the request emission to rings from the bookkeeping parts in add_request. Also move_to_active will fall apart once we start to reorder requests I think. Need to think about this case more, but we definitely need some testcases with depencies and reordering by the scheduler. -Daniel -- Daniel Vetter Software Engineer, Intel Corporation +41 (0) 79 365 57 48 - http://blog.ffwll.ch _______________________________________________ Intel-gfx mailing list [email protected] http://lists.freedesktop.org/mailman/listinfo/intel-gfx
