Knobs

OpenSWR has a number of environment variables which control its operation, in addition to the normal Mesa and gallium controls.

KNOB_ENABLE_ASSERT_DIALOGS Type: bool Default: true

Use dialogs when asserts fire. Asserts are only enabled in debug builds

KNOB_SINGLE_THREADED Type: bool Default: false

If enabled will perform all rendering on the API thread. This is useful mainly for debugging purposes.

KNOB_DUMP_SHADER_IR Type: bool Default: false

Dumps shader LLVM IR at various stages of jit compilation.

KNOB_USE_GENERIC_STORETILE Type: bool Default: false

Always use generic function for performing StoreTile. Will be slightly slower than using optimized (jitted) path

KNOB_FAST_CLEAR Type: bool Default: true

Replace 3D primitive execute with a SWRClearRT operation and defer clear execution to first backend op on hottile, or hottile store

KNOB_MAX_NUMA_NODES Type: uint32_t Default: 0

Maximum # of NUMA-nodes per system used for worker threads 0 == ALL NUMA-nodes in the system N == Use at most N NUMA-nodes for rendering

KNOB_MAX_CORES_PER_NUMA_NODE Type: uint32_t Default: 0

Maximum # of cores per NUMA-node used for worker threads. 0 == ALL non-API thread cores per NUMA-node N == Use at most N cores per NUMA-node

KNOB_MAX_THREADS_PER_CORE Type: uint32_t Default: 1

Maximum # of (hyper)threads per physical core used for worker threads. 0 == ALL hyper-threads per core N == Use at most N hyper-threads per physical core

KNOB_MAX_WORKER_THREADS Type: uint32_t Default: 0

Maximum worker threads to spawn. IMPORTANT: If this is non-zero, no worker threads will be bound to specific HW threads. They will all be “floating” SW threads. In this case, the above 3 KNOBS will be ignored.

KNOB_BUCKETS_START_FRAME Type: uint32_t Default: 1200

Frame from when to start saving buckets data. NOTE: KNOB_ENABLE_RDTSC must be enabled in core/knobs.h for this to have an effect.

KNOB_BUCKETS_END_FRAME Type: uint32_t Default: 1400

Frame at which to stop saving buckets data. NOTE: KNOB_ENABLE_RDTSC must be enabled in core/knobs.h for this to have an effect.

KNOB_WORKER_SPIN_LOOP_COUNT Type: uint32_t Default: 5000

Number of spin-loop iterations worker threads will perform before going to sleep when waiting for work

KNOB_MAX_DRAWS_IN_FLIGHT Type: uint32_t Default: 160

Maximum number of draws outstanding before API thread blocks.

KNOB_MAX_PRIMS_PER_DRAW Type: uint32_t Default: 2040

Maximum primitives in a single Draw(). Larger primitives are split into smaller Draw calls. Should be a multiple of (3 * vectorWidth).

KNOB_MAX_TESS_PRIMS_PER_DRAW Type: uint32_t Default: 16

Maximum primitives in a single Draw() with tessellation enabled. Larger primitives are split into smaller Draw calls. Should be a multiple of (vectorWidth).

KNOB_MAX_FRAC_ODD_TESS_FACTOR Type: float Default: 63.0f

(DEBUG) Maximum tessellation factor for fractional-odd partitioning.

KNOB_MAX_FRAC_EVEN_TESS_FACTOR Type: float Default: 64.0f

(DEBUG) Maximum tessellation factor for fractional-even partitioning.

KNOB_MAX_INTEGER_TESS_FACTOR Type: uint32_t Default: 64

(DEBUG) Maximum tessellation factor for integer partitioning.

KNOB_BUCKETS_ENABLE_THREADVIZ Type: bool Default: false

Enable threadviz output.

KNOB_TOSS_DRAW Type: bool Default: false

Disable per-draw/dispatch execution

KNOB_TOSS_QUEUE_FE Type: bool Default: false

Stop per-draw execution at worker FE NOTE: Requires KNOB_ENABLE_TOSS_POINTS to be enabled in core/knobs.h

KNOB_TOSS_FETCH Type: bool Default: false

Stop per-draw execution at vertex fetch NOTE: Requires KNOB_ENABLE_TOSS_POINTS to be enabled in core/knobs.h

KNOB_TOSS_IA Type: bool Default: false

Stop per-draw execution at input assembler NOTE: Requires KNOB_ENABLE_TOSS_POINTS to be enabled in core/knobs.h

KNOB_TOSS_VS Type: bool Default: false

Stop per-draw execution at vertex shader NOTE: Requires KNOB_ENABLE_TOSS_POINTS to be enabled in core/knobs.h

KNOB_TOSS_SETUP_TRIS Type: bool Default: false

Stop per-draw execution at primitive setup NOTE: Requires KNOB_ENABLE_TOSS_POINTS to be enabled in core/knobs.h

KNOB_TOSS_BIN_TRIS Type: bool Default: false

Stop per-draw execution at primitive binning NOTE: Requires KNOB_ENABLE_TOSS_POINTS to be enabled in core/knobs.h

KNOB_TOSS_RS Type: bool Default: false

Stop per-draw execution at rasterizer NOTE: Requires KNOB_ENABLE_TOSS_POINTS to be enabled in core/knobs.h