Re: [Intel-xe] [PATCH 00/10] Add OA functionality to Xe

["Dixit, Ashutosh" <ashutosh.dixit@intel.com>]

On Mon, 07 Aug 2023 18:31:49 -0700, Ashutosh Dixit wrote:
>

Hi Umesh/Lionel,

> This patchset is the initial port of i915 perf/OA functionality to the Xe
> driver. It has been tested against the following IGT patch:
>
> https://patchwork.freedesktop.org/series/121082/
>
> The following features in i915 have not been ported and will be added (as
> new patches) if/as they are needed:
>
> * Inline batch submission on stream exec_queue/hw_engine
> * NOA wait

About these two in the "not-yet-ported" feature list for Xe: In
i915 when a stream engine is specified, requests are submitted "inline" to
that engine whenever the OA stream is opened or reconfigured. This feature
is at present not ported to Xe (see xe_oa_submit_bb()).

I have a couple of questions about this "inline submission":

* Is inline submission a hard requirement? That is, in Xe can UMD's say
  (completely outside OA uapi) fence till a segment of the workload
  completes, then open/reconfigure the OA stream and then continue? If
  UMD's are able to do this we don't need inline submission in Xe. If UMD's
  cannot do this please explain why not.

* If inline submission is indeed required, can we do away with NOA wait (as
  implemented in daed3e44396d ("drm/i915/perf: implement active wait for
  noa configurations")) or implement NOA wait differently in Xe? E.g. can
  we expose a fence in the OA uapi and UMD's would be required to wait on
  this fence/sync-object before continuing workload submissions after any
  OA stream open/reconfiguration.

The reason I am brining this up is because in i915 there are a couple of
scary bugs around this which are still unresolved. E.g.:

	https://gitlab.freedesktop.org/drm/intel/-/issues/8746
	https://gitlab.freedesktop.org/drm/intel/-/issues/8190

There is therefore reason to think if this functionality can be done
differently in Xe (not to say these bugs will be carried over to Xe).

Thanks.
--
Ashutosh

> * GuC ctx id (guc_sw_ctx_id)
> * CTX_R_PWR_CLK_STATE/GEN8_R_PWR_CLK_STATE
> * hold_preemption (DRM_XE_OA_PROP_HOLD_PREEMPTION)
> * sseu_config (DRM_XE_OA_PROP_GLOBAL_SSEU)
> * Override gucrc (override_gucrc_mode)
> * MTL bios_c6_setup
> * ratelimits
> * compat ioctl
>
> I am providing the following additional HAX patch (not part of this series)
> to help review these patches:
>
> https://patchwork.freedesktop.org/patch/551683/?series=120100&rev=4
>
> The commit message in the above patch explains how it can be useful for
> reviewing this series.
>
> Test-with: 20230808010017.37819-1-ashutosh.dixit@intel.com
>
> v2: Fix build
> v3: Rebase, due to s/xe_engine/xe_exec_queue/
>
> Ashutosh Dixit (10):
>   drm/xe/oa: Introduce OA uapi
>   drm/xe/oa: Add OA types
>   drm/xe/oa: Add registers and GPU commands used by OA
>   drm/xe/oa: Module init/exit and probe/remove
>   drm/xe/oa: Add/remove config ioctl's
>   drm/xe/oa: Start implementing OA stream open ioctl
>   drm/xe/oa: OA stream initialization
>   drm/xe/oa: Expose OA stream fd
>   drm/xe/oa: Read file_operation
>   drm/xe/oa: Implement queries
>
>  drivers/gpu/drm/xe/Makefile               |    1 +
>  drivers/gpu/drm/xe/regs/xe_engine_regs.h  |    5 +
>  drivers/gpu/drm/xe/regs/xe_gpu_commands.h |   27 +
>  drivers/gpu/drm/xe/regs/xe_oa_regs.h      |  173 ++
>  drivers/gpu/drm/xe/xe_device.c            |   16 +
>  drivers/gpu/drm/xe/xe_device_types.h      |    4 +
>  drivers/gpu/drm/xe/xe_gt_types.h          |    4 +
>  drivers/gpu/drm/xe/xe_hw_engine_types.h   |    2 +
>  drivers/gpu/drm/xe/xe_module.c            |    5 +
>  drivers/gpu/drm/xe/xe_oa.c                | 2356 +++++++++++++++++++++
>  drivers/gpu/drm/xe/xe_oa.h                |   28 +
>  drivers/gpu/drm/xe/xe_oa_types.h          |  295 +++
>  drivers/gpu/drm/xe/xe_query.c             |    5 +-
>  include/uapi/drm/xe_drm.h                 |  257 ++-
>  14 files changed, 3176 insertions(+), 2 deletions(-)
>  create mode 100644 drivers/gpu/drm/xe/regs/xe_oa_regs.h
>  create mode 100644 drivers/gpu/drm/xe/xe_oa.c
>  create mode 100644 drivers/gpu/drm/xe/xe_oa.h
>  create mode 100644 drivers/gpu/drm/xe/xe_oa_types.h
>
> --
> 2.41.0
>