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

[Tvrtko Ursulin]

On 20/03/2024 15:06, Andi Shyti wrote:
> Ping! Any thoughts here?

I only casually observed the discussion after I saw Matt suggested 
further simplifications. As I understood it, you will bring back the 
uabi engine games when adding the dynamic behaviour and that is fine by me.

Regards,

Tvrtko

> 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