Re: [PATCH v4 12/38] drm/i915: Added scheduler hook into i915_gem_request_notify()

Chris Wilson
2016-01-11T22:14:54Z

On Mon, Jan 11, 2016 at 06:42:41PM +0000, John.C.Harrison@Intel.com wrote:
> From: John Harrison <John.C.Harrison@Intel.com>
>
> The scheduler needs to know when requests have completed so that it
> can keep its own internal state up to date and can submit new requests
> to the hardware from its queue.

Why would you reuse the user interrupt rather than introduce a
context-switch interrupt using the pipe_notify/dword_notify (yes, it can
be done by fixing up the current code). In the case of execlists you
wouldn't even need to add another interrupt vector as you could just
overload the execlists submission routine. For legacy, this would at
least let you reduce the interrupt rate from per batch to per context
switch, and keep the logic separate for user request tracking.
-Chris

--
Chris Wilson, Intel Open Source Technology Centre