On 1/28/20 4:49 PM, Matthew Brost wrote:
On Fri, Jan 24, 2020 at 04:55:31PM -0800, Daniele Ceraolo Spurio wrote:
Note: this applies on top of my series to commit early to GuC [1].
Picking up from the feedback from my RFC series about splitting
up intel_lrc.c [2], this series introduces GuC submission versions
of most of the engine and context functions. As a starting point,
the functions are still very similar to the execlists ones, but
they will progressively diverge while we add the new submission
logic. Some of the functions have been simplified by removing
support for pre-gen11 cases as we only aim to enable GuC submission
for gen11+; I've left comments and BUG_ONs to mark the reduces
support spots to easily find them in case we ever want to enable
GuC submission for older gens.
Going slightly against the feedback from the previous series, I have
kept the basic context and ring object management shared between
execlists and GuC submission functions. The rationale is that those
objects are HW-related and therefore their creation and their main
attributes (e.g. context size) are not dependent on the submission
method in any way. Handling of more SW constructs, like the timeline,
has been duplicated.
Still in theme of sharing, the flush and bb_start functions have also
been re-used on the GuC side, but I'm not sure if keeping them in
intel_lrc.c is the best solution. My medium-term plan is still the same
as [2], i.e. split execlists_submission.c out of intel_lrc.c, with the
latter holding the common code, but it might be worth moving the
command emission to a dedicated file or to a header as inlines, like
we already do in some cases.
I can't say I'm thrilled about the amount of code duplicated in this
series.
i.e. 95% of the breadcrumb code is exactly the same, request_alloc is a
copy and
paste, same with resume, and same with the context operations. Surely
there is a
way to share the code common between the GuC execlists? I like the idea of
I do understand the concerns as I started with the same idea you have
(see my RFC for splitting intel_lrc.c), but after the received feedback
and looking a bit more at the flows I've partially changed my mind,
because not all that make sense to have in a common place today will
stay the same going forward. e.g. we'll have to add a semaphore_signal
to the breadcrumb_fini to signal completion to the GuC if we want the
GuC to handle the dependencies for us, which will impact both the
breadcrumb code itself and the size used in request_alloc.
This said, I do agree that there is certainly the opportunity to move
more code to be common than what is done in this series, but IMO we need
to wait for all the bits to be in place to have a clearer picture of
what the full flow is going to look like. We did go through something
similar, but on a bigger scale, when we duplicated everything from
ringbuffer to execlists submission and then gradually merged it back
together where possible.
Also, consider that some functions are back-end level, so IMO we need to
compare them with their ringbuffer version as well.
Daniele
putting all of this common code in a shared file and then
intel_execlist_submission.c & intel_guc_submission.c call into the common
functions while retaining there own set of unique function pointers.
Matt
The code is still a bit rough and the series has been compile-tested
only. I wanted to get some early comments about the direction before
rebasing the rest of the GuC code on top of it and start testing.
[1] https://patchwork.freedesktop.org/series/72031/
[2] https://patchwork.freedesktop.org/series/70787/
Cc: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Cc: Michal Wajdeczko <michal.wajdeczko@xxxxxxxxx>
Cc: John Harrison <John.C.Harrison@xxxxxxxxx>
Cc: Matthew Brost <matthew.brost@xxxxxxxxx>
Daniele Ceraolo Spurio (6):
drm/i915/guc: Add guc-specific breadcrumb functions
drm/i915/guc: Add request_alloc for guc_submission
drm/i915/guc: Add engine->resume for GuC submission
drm/i915/guc: Re-use lrc flush functions
drm/i915/guc: Add initial context ops for GuC submission
drm/i915/guc: Stop inheriting from execlists_set_default_submission
drivers/gpu/drm/i915/gt/intel_lrc.c | 217 +++++-----
drivers/gpu/drm/i915/gt/intel_lrc.h | 17 +-
drivers/gpu/drm/i915/gt/selftest_lrc.c | 12 +-
.../gpu/drm/i915/gt/uc/intel_guc_submission.c | 378 +++++++++++++++++-
4 files changed, 496 insertions(+), 128 deletions(-)
--
2.24.1
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