11. dasLLAMA environment variables

GENERATED from env_registry() in dasllama/dasllama_env.das — do not edit by hand. Regenerate with daslang modules/dasLLAMA/harness/gen_env_doc.das; a knob read anywhere in the tree without a registry entry fails tests/test_env_registry.das.

Types: flag is unset-means-default, 0/false/off/no/empty is false and anything else true; number falls back to the default when unset or unparseable; text and path are taken verbatim. Every read goes through env_flag / env_int / env_int64 / env_str, so the rules are the same everywhere.

A knob is read ONCE, at init or behind a one-time gate — reading the environment on a per-token path is what PERF027 exists to catch (see skills/perf_lint.md).

11.1. Engine

Read by the inference engine itself, so these affect any program that loads a model.

Variable	Type	Default	Effect
DASLLAMA_IMAGE	flag	on	Use the prepared-image cache beside a .gguf for millisecond reloads; 0 forces a full parse.
DASLLAMA_CPU_PREFILL	flag	off	Allow the CPU prefill path even when a GPU prefill override is registered.
DASLLAMA_PIN_PREFILL	text	unset	Pin prefill to one registered override by name (e.g. metal, vulkan); anything else declines before upload.
DASLLAMA_PIN_BACKEND	text	unset	Pin the matmul backend by name, bypassing the measured auto-selection.
DASLLAMA_PIN_BATCH_BACKEND	text	unset	Pin the batched (prefill) matmul backend independently of the decode one.
DASLLAMA_EXPERT_REUSE	flag	off	Arm the MoE expert-reuse counter (probes and servers; benches use set_expert_reuse instead).
DASLLAMA_NOISY	flag	off	Print engine diagnostics (tier selection, upload plan, arm/decline reasons).
DASLLAMA_CALLER_PRIO	number	unset	A/B rail for the dispatch caller’s thread priority, -2..2; unset claims the top notch.
DASLLAMA_TRUTH_REFRESH	flag	off	Regenerate the stored parity truth files instead of comparing against them.
DASLLAMA_GPU	flag	off	One switch for the measured-best GPU rail set; any DASLLAMA_GPU_* knob still overrides individually.
DASLLAMA_GPU_MOE_LAYERS	number	-1 (auto)	How many MoE expert layers to hold resident on the GPU; -1 lets the upload walk place the split.
DASLLAMA_GPU_MOE_STREAM	number	-1 (auto)	How many MoE layers to stream rather than hold resident; -1 is auto.
DASLLAMA_GPU_VRAM_MB	number	probed	Override the detected VRAM budget in MiB that sizes the resident expert stacks.
DASLLAMA_GPU_MIN_CTX	number	built-in floor	Lower the context floor for arming the resident decode driver, for a short-context session on a small card.
DASLLAMA_GPU_DN	flag	follows DASLLAMA_GPU	DeltaNet rail on the GPU.
DASLLAMA_GPU_DND	flag	follows DASLLAMA_GPU	DeltaNet decode rail on the GPU.
DASLLAMA_GPU_ATTN	flag	follows DASLLAMA_GPU	Attention rail on the GPU.
DASLLAMA_GPU_DENSE	flag	follows DASLLAMA_GPU	Dense-weight rail on the GPU.
DASLLAMA_GPU_DENSE_ATTN	flag	on	The dense rail’s attention half (per-layer q/o pairs); opt-OUT, measured a loss on gemma-4.
DASLLAMA_GPU_DENSE_SHEXP	flag	off	The dense rail’s gemma-4 shared-expert w1/w3/w2 triple; opt-IN, measured a wash-to-loss.
DASLLAMA_GPU_SHEXP	flag	follows DASLLAMA_GPU	Shared-expert rail on the GPU.
DASLLAMA_GPU_QKV	flag	off	Fused QKV rail on the GPU; stays off under DASLLAMA_GPU (measured a wash).
DASLLAMA_GPU_CLS	flag	on	Keep the classifier plane on the GPU — the best ms-per-GB region; 0 is the CPU A/B lever.
DASLLAMA_GPU_COMBINE	flag	on	Device-side routed MoE combine; 0 falls back to the host combine.
DASLLAMA_GPU_HEAT	number	0	Expert heat threshold: hold the N hottest experts resident regardless of layer placement.
DASLLAMA_GPU_PROF	flag	off	Report lifetime GPU queue submissions (real commands plus staging round-trips).

11.2. Metal backend

Apple GPU backend. Absent on non-Apple builds, where setting them does nothing.

Variable	Type	Default	Effect
DASLLAMA_METAL_LOGITS	flag	on	Produce logits on the GPU; 0 pulls the classifier back to the CPU. Blob-only models force it on.
DASLLAMA_METAL_ATTN	flag	on	ggml-geometry QK/AV prefill attention (~10x the trio GEMMs); 0 pins the trio.
DASLLAMA_METAL_ATTN_D	flag	on	Fused single-pass decode attention (assumes head_size 128); 0 is the A/B rail to the chunked pair.
DASLLAMA_METAL_ATTN_SINGLE	number	64	Row count below which attention uses the single-chunk kernel; clamped to 128.
DASLLAMA_METAL_MULMM	flag	on	The mul_mm prefill GEMM; 0 falls back to the legacy per-op path.
DASLLAMA_METAL_NCB	number	~4 layers/chunk	Command-buffer split: each chunk commits as encoded so the scheduler overlaps chunk k with k-1.
DASLLAMA_METAL_UNRETAINED	flag	off	Skip per-dispatch retain/release on the prefill command buffers.
DASLLAMA_METAL_PF_CAPTURE	flag	on	Record each prefill chunk as a step graph and replay on a concurrent encoder; 0 is serial-encode rollback.
DASLLAMA_METAL_SCHED	number	1	Graph scheduling mode for replay; 0 keeps capture order.
DASLLAMA_METAL_DECODE_CONCURRENT	flag	on	Concurrent encoder for the single-stream decode step, with barriers only at detected hazards.
DASLLAMA_METAL_FUSE	flag	on	The R1 epilogue-fusion kernel (post_attn_rms + add_rms); 0 restores separate dispatches for A/B.
DASLLAMA_METAL_SPEC	number	-1 (adaptive)	MTP speculative decode chain: 0 off, 1 forced, -1 adaptive.
DASLLAMA_METAL_GEMV_TG	number	4	Rows per GEMV threadgroup, clamped 1..32.
DASLLAMA_METAL_KQ_B8	flag	on	Single-pass B8 twin for K-quant small-batch mv at B=5..8; 0 is the A/B rail.
DASLLAMA_METAL_KV_MIRROR_MB	number	4096	Ceiling in MiB for the device-side KV mirror, clamped 64..4096.
DASLLAMA_METAL_HAZARD_PARANOID	flag	off	Barrier at every dispatch instead of at tracker-detected hazards (correctness bisect).
DASLLAMA_METAL_HAZARD_STRICT	flag	off	Treat every detected hazard as strict, widening barriers (correctness bisect).
DASLLAMA_METAL_PIPE_DEBUG	flag	off	Per-step pipeline trace: GPU envelope and true inter-step handoff idle, first steps plus outliers.
DASLLAMA_METAL_DECODE_SKIP	text	unset	Comma-separated dispatch names to skip in decode — a bring-up bisect that breaks correctness.
DASLLAMA_METAL_PREFILL_SKIP	text	unset	Prefill twin of DASLLAMA_METAL_DECODE_SKIP.
DASLLAMA_MTP_DEBUG	text	unset	MTP bring-up bisect: cold logs the failing gate, reject forces the reject path.
DASLLAMA_METAL_BATCH_GEMM_MIN	number	5	Batch size at which batched decode switches from GEMV to GEMM; floor 2.
DASLLAMA_METAL_BATCH_SK	flag	on	Split-K in the batched decode GEMM.
DASLLAMA_METAL_BATCH_NCB	number	4	Command buffers per batched decode step, clamped 1..16.
DASLLAMA_METAL_BATCH_CONCURRENT	flag	on	Concurrent encoder for batched decode.
DASLLAMA_METAL_BATCH_FUSE	flag	on	Epilogue fusion in batched decode.
DASLLAMA_METAL_BATCH_MV	flag	on	Fixed-B GEMV forms for small batched decode.
DASLLAMA_METAL_BATCH_MV8	flag	on	The column-tiling MV8 probe for batched decode.
DASLLAMA_METAL_BATCH_PIPE	flag	off	Pipelined batched decode submission.
DASLLAMA_METAL_BATCH_MM	flag	off	The mul_mm rail for batched decode; measured negative at M-pad-32, kept as the A/B rail.

11.3. Vulkan backend

Vulkan GPU backend. Present only where the dasVulkan package is installed.

Variable	Type	Default	Effect
DASLLAMA_COOPMAT	number	auto	Cooperative-matrix mode; the flash-attention twin needs it even when the GEMM runs sdot4.
DASLLAMA_MM_SMALL	number	32	Small-batch tier: 32 = sdot4 (default, beats both coopmat tiles below the crossover), 64 = coopmat M, 128 = always-L.
DASLLAMA_VK_FA	flag	on	Vulkan flash-attention kernel; 0 falls back to the chunked path.
DASLLAMA_VK_REBAR	flag	on	Use a ReBAR device-local host-visible heap when one larger than 1GB is present.
DASLLAMA_VK_HAZARD_PARANOID	flag	off	Barrier at every dispatch (correctness bisect).
DASLLAMA_VK_HAZARD_TRACE	flag	off	Log every detected hazard and the barrier it produced.

11.4. Accelerate / AMX backend

Apple Accelerate / AMX float lane. DASLLAMA_ACCEL arms the whole group.

Variable	Type	Default	Effect
DASLLAMA_ACCEL	flag	off	Arm the Apple Accelerate / AMX float-batch override.
DASLLAMA_ACCEL_F16	flag	off	Use the BNNS f16 lane inside the Accelerate backend.
DASLLAMA_ACCEL_F16_STRIPS	number	0	Strip count for the f16 lane; 0 lets the backend choose.
DASLLAMA_ACCEL_MIN_MMAC	number	backend default	Minimum MMAC count below which Accelerate declines and the daslang kernel runs.
DASLLAMA_ACCEL_MIN_NTOK	number	32	Minimum token count for the Accelerate float-batch override, floor 1.

11.5. Harness — tuner and probes

Variable	Type	Default	Effect
DASLLAMA_MODELS_DIR	path	unset	Directory holding the .gguf models the probes, benches and tests load.
DASLLAMA_CONFIRM_MODEL	path	unset	Model used by the tuner’s confirm gate. Must be a FULL path, not a bare filename.
DASLLAMA_BATCH_CHUNKS	number	unset	Override the batched-dispatch chunk count in the 1-core GEMM probe.
DASLLAMA_BATCH_GRID_2D	flag	off	Use the 2D batch grid in the parity probe.
DASLLAMA_FOCUS_BACKEND	text	unset	Restrict the 1-core GEMM probe to one backend.
DASLLAMA_FOCUS_SHAPE	text	unset	Restrict the 1-core GEMM probe to one shape.
DASLLAMA_FOCUS_NTOK	number	unset	Restrict the 1-core GEMM probe to one token count.
DASLLAMA_FOCUS_FORKED	flag	off	Run the 1-core GEMM probe through the fork pool rather than inline.
GEN_TUNE_COMPILE_ONLY	flag	off	Compile the generated tune probe without running it.
SMMLA_PROBE_COMPILE_ONLY	flag	off	Compile the smmla probe without running it.
METAL	flag	off	Run the Accelerate contention probe against the Metal backend.
DAS_DETAIL	flag	off	Per-job dump in the dispatch probe.
DAS_SPIN_NS	number	unset	Synthetic per-job spin in nanoseconds for the dispatch probe.
DAS_BATCH_DISPATCH	flag	off	Exercise batched dispatch in the dispatch probe.
DAS_TWO_WAVE	flag	off	Exercise the two-wave dispatch shape in the dispatch probe.
DAS_FORK_SKIP_HEAP_RESET	flag	off	Skip restartHeaps on pooled fork-context reuse (A/B for the fork-pool heap cost).
DAS_WORKER_SPIN_US	number	unset	Worker spin-before-park window in microseconds, applied via set_jobque_spin_us.
DAS_JOBQUE_JOIN_SPIN	number	unset	Join-side spin window for the 1-core GEMM probe.

11.6. Benchmarks

Variable	Type	Default	Effect
DASLLAMA_BENCH_MODEL	text	tinyllama	Model name for the isolated GEMM bench.
DASLLAMA_BENCH_NTOK	number	unset	Token count for the isolated GEMM bench.
DASLLAMA_BENCH_SKIP_ROWMAJOR	flag	off	Skip the row-major arm of the isolated GEMM bench.
DASLLAMA_BENCH_VERBOSE	flag	off	Per-run detail from the llama.cpp comparison bench.
DASLLAMA_MIN_CHUNK_ROWS	number	unset	Override the minimum rows per dispatch chunk in the GEMM bench.
DASLLAMA_FUSED_DECODE	flag	off	Exercise the fused decode arm in the emission bench.
DASMETAL_LAB_ROUNDS	number	3	Timing rounds per cell in the Metal kernel labs.
DASMETAL_LAB_PASSES	number	4	Passes per round in the Metal MoE lab.
DASMETAL_LAB_ATTN_NSGS	number	16	Simdgroups per threadgroup in the Metal attention lab.
DASMETAL_LAB_DUMP_MSL	flag	off	Dump generated MSL from the Metal labs instead of running it.

11.7. Profiling and baselines

Variable	Type	Default	Effect
DASLLAMA_GPU_NAME	text	probed	Override the GPU name recorded in a box profile.
DASLANG_BIN	path	bin/daslang	daslang binary the profiling harness shells out to.
DASLLAMA_BOX	text	probed	Override the box identifier recorded in a profile.
DASLLAMA_CPU	text	probed	Override the CPU name recorded in a profile.
DASLLAMA_OS	text	probed	Override the OS name recorded in a profile.
DASLLAMA_RAM_GB	number	probed	Override the RAM size in GiB recorded in a profile.
DASLLAMA_THREADS	number	probed	Override the thread count recorded in a profile.
LLAMA_BENCH	path	unset	Path to the llama-bench binary used to establish reference baselines.
LLAMA_BENCH_CLEAN	path	unset	Path to a clean-build llama-bench for the reference column.
LLAMA_BENCH_STOCK	path	unset	Path to a stock-build llama-bench for the reference column.
WHISPER_CPP	path	unset	whisper.cpp checkout used for ASR reference baselines.
WHISPER_CPP_MODELS	path	unset	Directory of whisper.cpp models for ASR reference baselines.
MTMD_BIN	path	unset	llama-mtmd-cli binary for multimodal reference baselines.
NEMO_PY	path	unset	Python interpreter of the NeMo oracle venv, for canary/parakeet baselines.
ONNX_PY	path	unset	Python interpreter of the ONNX oracle venv, for parakeet baselines.
OS	text	set by Windows	Read to detect Windows (Windows_NT); set by the OS, not by dasLLAMA.
PROCESSOR_ARCHITECTURE	text	set by Windows	Read for the CPU architecture on Windows; set by the OS, not by dasLLAMA.
NUMBER_OF_PROCESSORS	number	set by Windows	Read for the core count on Windows; set by the OS, not by dasLLAMA.

11.8. Tests

Variable	Type	Default	Effect
DASLLAMA_PARITY_FULL	flag	off	Run the FULL parity matrix. Without it the big-model rows silently skip.
DASLLAMA_TEST_ARMS	text	unset	Comma-separated filter restricting which parity arms run.
DASLLAMA_TEST_FAMILY	text	unset	Comma-separated filter restricting which model families run.
DASLLAMA_LLAMA2C_DIR	path	unset	Directory of llama2.c reference checkpoints for the forward/decode parity tests.
DASLLAMA_WHISPER_DIR	path	unset	Directory of whisper models for the audio tests.
DASLLAMA_CORPUS_DIR	path	unset	Directory of audio corpus files for the transcription tests.
TMPDIR	path	/tmp	Scratch directory for test artifacts; set by the OS on macOS.

11.9. Examples and tutorials

Variable	Type	Default	Effect
DASLLAMA_MODEL	path	unset	Model path for the dasLLAMA tutorials when none is passed on the command line.

11.10. daslang core knobs dasLLAMA honours

Owned by daslang, not by dasLLAMA — listed because dasLLAMA’s behaviour depends on them. DAS_TUNE_* is covered in skills/tune.md.

Variable	Type	Default	Effect
DAS_JOBQUE_THREADS	number	conservative default	Total compute lanes for job queues (N-1 workers plus the caller). Overrides set_jobque_threads_cap; see skills/environment_variables.md.
DAS_JOBQUE_AFFINITY	number	0	Worker affinity: 0 off, 1 ideal-processor hint, 2 hard mask. Matters on big SMT boxes.
DAS_JOBQUE_TEAM_RANK_GATE	number	profile-driven	Team-dispatch rank gate. When set, it suppresses the box profile’s own team_rank_gate knob.
DAS_TUNE_MANIFEST	path	.tune.json	Kernel-tuning sidecar to read/write. Point it somewhere writable when the app dir is read-only.
DAS_TUNE_MODE	text	unset	Kernel-tuning mode. The [tune] framework owns these; see skills/tune.md.
DAS_TUNE_POLICY	text	unset	Kernel-tuning policy override. The [tune] framework owns these; see skills/tune.md.
DAS_TUNE_COMPILE_FALLBACKS	text	unset	Semicolon-separated kernel fallbacks for the generated tune probe.