RE: [PATCH v6 0/3] Disable automatic load CCS load balancing

From: "Mrozek, Michal" <michal.mrozek@intel.com>
To: Andi Shyti <andi.shyti@linux.intel.com>
Cc: intel-gfx <intel-gfx@lists.freedesktop.org>,
	dri-devel <dri-devel@lists.freedesktop.org>,
	Chris Wilson <chris.p.wilson@linux.intel.com>,
	Joonas Lahtinen <joonas.lahtinen@linux.intel.com>,
	"Roper, Matthew D" <matthew.d.roper@intel.com>,
	"Harrison, John C" <john.c.harrison@intel.com>,
	"stable@vger.kernel.org" <stable@vger.kernel.org>,
	Andi Shyti <andi.shyti@kernel.org>,
	Tvrtko Ursulin <tursulin@ursulin.net>,
	"Buxton, Mark J" <mark.j.buxton@intel.com>
Subject: RE: [PATCH v6 0/3] Disable automatic load CCS load balancing
Date: Tue, 26 Mar 2024 16:25:26 +0000	[thread overview]
Message-ID: <BN9PR11MB5275951CE65489FEAA8BA9BFE7352@BN9PR11MB5275.namprd11.prod.outlook.com> (raw)
In-Reply-To: <ZgL2o7c0R_Z7shFJ@ashyti-mobl2.lan>

On Wed, Mar 13, 2024 at 09:19:48PM +0100, Andi Shyti wrote:
> Hi,
> 
> this series does basically two things:
> 
> 1. Disables automatic load balancing as adviced by the hardware
>    workaround.
> 
> 2. Assigns all the CCS slices to one single user engine. The user
>    will then be able to query only one CCS engine
> 
> >From v5 I have created a new file, gt/intel_gt_ccs_mode.c where
> I added the intel_gt_apply_ccs_mode(). In the upcoming patches, this 
> file will contain the implementation for dynamic CCS mode setting.
> 
> Thanks Tvrtko, Matt, John and Joonas for your reviews!
> 
> Andi
> 
> Changelog
> =========
> v5 -> v6 (thanks Matt for the suggestions in v6)
>  - Remove the refactoring and the for_each_available_engine()
>    macro and instead do not create the intel_engine_cs structure
>    at all.
>  - In patch 1 just a trivial reordering of the bit definitions.
> 
> v4 -> v5
>  - Use the workaround framework to do all the CCS balancing
>    settings in order to always apply the modes also when the
>    engine resets. Put everything in its own specific function to
>    be executed for the first CCS engine encountered. (Thanks
>    Matt)
>  - Calculate the CCS ID for the CCS mode as the first available
>    CCS among all the engines (Thanks Matt)
>  - create the intel_gt_ccs_mode.c function to host the CCS
>    configuration. We will have it ready for the next series.
>  - Fix a selftest that was failing because could not set CCS2.
>  - Add the for_each_available_engine() macro to exclude CCS1+ and
>    start using it in the hangcheck selftest.
> 
> v3 -> v4
>  - Reword correctly the comment in the workaround
>  - Fix a buffer overflow (Thanks Joonas)
>  - Handle properly the fused engines when setting the CCS mode.
> 
> v2 -> v3
>  - Simplified the algorithm for creating the list of the exported
>    uabi engines. (Patch 1) (Thanks, Tvrtko)
>  - Consider the fused engines when creating the uabi engine list
>    (Patch 2) (Thanks, Matt)
>  - Patch 4 now uses a the refactoring from patch 1, in a cleaner
>    outcome.
> 
> v1 -> v2
>  - In Patch 1 use the correct workaround number (thanks Matt).
>  - In Patch 2 do not add the extra CCS engines to the exposed
>    UABI engine list and adapt the engine counting accordingly
>    (thanks Tvrtko).
>  - Reword the commit of Patch 2 (thanks John).
> 
> Andi Shyti (3):
>   drm/i915/gt: Disable HW load balancing for CCS
>   drm/i915/gt: Do not generate the command streamer for all the CCS
>   drm/i915/gt: Enable only one CCS for compute workload
> 
>  drivers/gpu/drm/i915/Makefile               |  1 +
>  drivers/gpu/drm/i915/gt/intel_engine_cs.c   | 20 ++++++++---
>  drivers/gpu/drm/i915/gt/intel_gt_ccs_mode.c | 39 
> +++++++++++++++++++++  drivers/gpu/drm/i915/gt/intel_gt_ccs_mode.h | 13 +++++++
>  drivers/gpu/drm/i915/gt/intel_gt_regs.h     |  6 ++++
>  drivers/gpu/drm/i915/gt/intel_workarounds.c | 30 ++++++++++++++--
>  6 files changed, 103 insertions(+), 6 deletions(-)  create mode 
> 100644 drivers/gpu/drm/i915/gt/intel_gt_ccs_mode.c
>  create mode 100644 drivers/gpu/drm/i915/gt/intel_gt_ccs_mode.h
> 
> --
> 2.43.0

Acked-by: Michal Mrozek <michal.mrozek@intel.com>