[Intel-gfx] [RFC 0/8] Per client engine busyness

Tvrtko Ursulin
2020-01-10T13:30:55Z

From: Tvrtko Ursulin <tvrtko.ursulin@intel.com>

Another re-spin of the per-client engine busyness series. Highlights from this
version:

* Two patches added on top of the series to provide the data in GuC mode.
(For warnings and limitations please read the respective commit messages.)
* Refactor to introduce a notion of i915_drm_client and move to separate source
file.

Internally we track time spent on engines for each struct intel_context. This
can serve as a building block for several features from the want list:
smarter scheduler decisions, getrusage(2)-like per-GEM-context functionality
wanted by some customers, cgroups controller, dynamic SSEU tuning,...

Externally, in sysfs, we expose time spent on GPU per client and per engine
class.

Sysfs interface enables us to implement a "top-like" tool for GPU tasks. Or with
a "screenshot":
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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 | || || || |
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Implementation wise we add a a bunch of files in sysfs like:

# 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.

Tvrtko Ursulin (8):
drm/i915: Expose list of clients in sysfs
drm/i915: Update client name on context create
drm/i915: Track per-context engine busyness
drm/i915: Track all user contexts per client
drm/i915: Contexts can use struct pid stored in the client
drm/i915: Expose per-engine client busyness
drm/i915: Track hw reported context runtime
drm/i915: Fallback to hw context runtime when sw tracking is not
available

drivers/gpu/drm/i915/Makefile | 3 +-
drivers/gpu/drm/i915/gem/i915_gem_context.c | 60 +++-
.../gpu/drm/i915/gem/i915_gem_context_types.h | 16 +-
drivers/gpu/drm/i915/gt/intel_context.c | 20 ++
drivers/gpu/drm/i915/gt/intel_context.h | 18 ++
drivers/gpu/drm/i915/gt/intel_context_types.h | 14 +
drivers/gpu/drm/i915/gt/intel_engine_cs.c | 16 +-
drivers/gpu/drm/i915/gt/intel_lrc.c | 55 +++-
drivers/gpu/drm/i915/i915_debugfs.c | 7 +-
drivers/gpu/drm/i915/i915_drm_client.c | 298 ++++++++++++++++++
drivers/gpu/drm/i915/i915_drm_client.h | 83 +++++
drivers/gpu/drm/i915/i915_drv.h | 5 +
drivers/gpu/drm/i915/i915_gem.c | 35 +-
drivers/gpu/drm/i915/i915_gpu_error.c | 8 +-
drivers/gpu/drm/i915/i915_sysfs.c | 8 +
drivers/gpu/drm/i915/intel_device_info.c | 2 +
drivers/gpu/drm/i915/intel_device_info.h | 1 +
17 files changed, 606 insertions(+), 43 deletions(-)
create mode 100644 drivers/gpu/drm/i915/i915_drm_client.c
create mode 100644 drivers/gpu/drm/i915/i915_drm_client.h

--
2.20.1