[PATCH 0/7] Per client engine busyness

[Alex Deucher]

On Thu, May 13, 2021 at 7:00 AM Tvrtko Ursulin
<tvrtko.ursulin at linux.intel.com> wrote:
>
> From: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
>
> Resurrect of the previosuly merged per client engine busyness patches. In a
> nutshell it enables intel_gpu_top to be more top(1) like useful and show not
> only physical GPU engine usage but per process view as well.
>
> Example screen capture:
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> intel-gpu-top -  906/ 955 MHz;    0% RC6;  5.30 Watts;      933 irqs/s
>
>       IMC reads:     4414 MiB/s
>      IMC writes:     3805 MiB/s
>
>           ENGINE      BUSY                                      MI_SEMA MI_WAIT
>      Render/3D/0   93.46% |████████████████████████████████▋  |      0%      0%
>        Blitter/0    0.00% |                                   |      0%      0%
>          Video/0    0.00% |                                   |      0%      0%
>   VideoEnhance/0    0.00% |                                   |      0%      0%
>
>   PID            NAME  Render/3D      Blitter        Video      VideoEnhance
>  2733       neverball |██████▌     ||            ||            ||            |
>  2047            Xorg |███▊        ||            ||            ||            |
>  2737        glxgears |█▍          ||            ||            ||            |
>  2128           xfwm4 |            ||            ||            ||            |
>  2047            Xorg |            ||            ||            ||            |
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
> Internally we track time spent on engines for each struct intel_context, both
> for current and past contexts belonging to each open DRM file.
>
> This can serve as a building block for several features from the wanted list:
> smarter scheduler decisions, getrusage(2)-like per-GEM-context functionality
> wanted by some customers, setrlimit(2) like controls, cgroups controller,
> dynamic SSEU tuning, ...
>
> To enable userspace access to the tracked data, we expose time spent on GPU per
> client and per engine class in sysfs with a hierarchy like the below:
>
>         # cd /sys/class/drm/card0/clients/
>         # tree
>         .
>         ├── 7
>         │   ├── busy
>         │   │   ├── 0
>         │   │   ├── 1
>         │   │   ├── 2
>         │   │   └── 3
>         │   ├── name
>         │   └── pid
>         ├── 8
>         │   ├── busy
>         │   │   ├── 0
>         │   │   ├── 1
>         │   │   ├── 2
>         │   │   └── 3
>         │   ├── name
>         │   └── pid
>         └── 9
>             ├── busy
>             │   ├── 0
>             │   ├── 1
>             │   ├── 2
>             │   └── 3
>             ├── name
>             └── pid
>
> Files in 'busy' directories are numbered using the engine class ABI values and
> they contain accumulated nanoseconds each client spent on engines of a
> respective class.

We did something similar in amdgpu using the gpu scheduler.  We then
expose the data via fdinfo.  See
https://cgit.freedesktop.org/drm/drm-misc/commit/?id=1774baa64f9395fa884ea9ed494bcb043f3b83f5
https://cgit.freedesktop.org/drm/drm-misc/commit/?id=874442541133f78c78b6880b8cc495bab5c61704

Alex


>
> Tvrtko Ursulin (7):
>   drm/i915: Expose list of clients in sysfs
>   drm/i915: Update client name on context create
>   drm/i915: Make GEM contexts track DRM clients
>   drm/i915: Track runtime spent in closed and unreachable GEM contexts
>   drm/i915: Track all user contexts per client
>   drm/i915: Track context current active time
>   drm/i915: Expose per-engine client busyness
>
>  drivers/gpu/drm/i915/Makefile                 |   5 +-
>  drivers/gpu/drm/i915/gem/i915_gem_context.c   |  61 ++-
>  .../gpu/drm/i915/gem/i915_gem_context_types.h |  16 +-
>  drivers/gpu/drm/i915/gt/intel_context.c       |  27 +-
>  drivers/gpu/drm/i915/gt/intel_context.h       |  15 +-
>  drivers/gpu/drm/i915/gt/intel_context_types.h |  24 +-
>  .../drm/i915/gt/intel_execlists_submission.c  |  23 +-
>  .../gpu/drm/i915/gt/intel_gt_clock_utils.c    |   4 +
>  drivers/gpu/drm/i915/gt/intel_lrc.c           |  27 +-
>  drivers/gpu/drm/i915/gt/intel_lrc.h           |  24 ++
>  drivers/gpu/drm/i915/gt/selftest_lrc.c        |  10 +-
>  drivers/gpu/drm/i915/i915_drm_client.c        | 365 ++++++++++++++++++
>  drivers/gpu/drm/i915/i915_drm_client.h        | 123 ++++++
>  drivers/gpu/drm/i915/i915_drv.c               |   6 +
>  drivers/gpu/drm/i915/i915_drv.h               |   5 +
>  drivers/gpu/drm/i915/i915_gem.c               |  21 +-
>  drivers/gpu/drm/i915/i915_gpu_error.c         |  31 +-
>  drivers/gpu/drm/i915/i915_gpu_error.h         |   2 +-
>  drivers/gpu/drm/i915/i915_sysfs.c             |   8 +
>  19 files changed, 716 insertions(+), 81 deletions(-)
>  create mode 100644 drivers/gpu/drm/i915/i915_drm_client.c
>  create mode 100644 drivers/gpu/drm/i915/i915_drm_client.h
>
> --
> 2.30.2
>