11. dasLLAMA environment variables

GENERATED from the [EnvConfig] declarations 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 declaration fails tests/test_env_registry.das.

Types: flag is unset-means-default, 0/false/off/no (any case) is false and anything else true; number falls back to the default when unset or unparseable, with a logged warning on garbage; text and path are taken verbatim. A SET-BUT-EMPTY variable counts as unset everywhere. Every knob loads ONCE, at context init, into the g_env_* globals - hot code reads struct fields, and set_env_variable after startup is invisible (arm a child process’s environment instead).

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 file beside a source model for millisecond reloads. 0 skips the file: LLM ggufs take the full parse; audio carriers mint the image in memory and serve that (they are always image-backed).
DASLLAMA_IMAGE_SAVE	flag	on	Persist the prepared image beside the source; 0 builds it in memory and serves that, leaving no .dlim behind.
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	2 (the top notch)	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_CONV_PROF	flag	off	Bucket gguf -> image conversion time by kind over the weight walk; one clock pair per tensor.
DASLLAMA_ALLOW_INTERP_LOAD	flag	off	Permit a big gguf load without -jit; the transforms run interpreted, so expect minutes per GB.
DASLLAMA_PREFETCH	flag	on	Advisory source-mapping readahead at gguf load (cold-conversion fix); =0 restores on-demand faulting.
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. Vision

The image preprocessing rail: dynamic-resolution token bounds and the debug dump.

Variable	Type	Default	Effect
DASLLAMA_VISION_MIN_TOKENS	number	40 (the gemma-4 model default)	Minimum soft tokens per image; dynamic-resolution geometry upscales to reach it.
DASLLAMA_VISION_MAX_TOKENS	number	280 (the gemma-4 model default)	Maximum soft tokens per image; dynamic-resolution geometry downscales to fit.
DASLLAMA_VISION_DUMP	text	unset	Path prefix: dump every letterboxed image fed to a vision embedder as .ppm — the human smoke test; empty = off.

11.3. 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_SPAN	flag	on	Serve the non-causal media span on the prefill driver (AttnArgs.uend); 0 declines it to the CPU arm, which then needs declared CPU intent.
DASLLAMA_METAL_TOWER	flag	on	Serve tower/embedder encodes (gemma4uv; the whisper-class towers as they land) on the Metal tower driver; 0 pins the CPU tower.
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.

11.4. Vulkan backend

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

Variable	Type	Default	Effect
DASLLAMA_COOPMAT	text	auto	Cooperative-matrix mode; the flash-attention twin needs it even when the GEMM runs sdot4.
DASLLAMA_MM_SMALL	text	32	Small-batch tier: 32 = sdot4 (default, beats both coopmat tiles below the crossover), 64 = coopmat M, 128 = always-L.
DASLLAMA_MM_SMALLD	number	64	Small-d cutoff routing narrow roles (k/v) to the small tier; widening measured worse, so this is an instrument.
DASLLAMA_VK_FUSE	flag	on	Fused decode tail (add+rms+requant, qk-norm+rope); 0 pins the split dispatches for a same-build A/B.
DASLLAMA_VK_XFERQ	flag	on	Stream expert uploads on the dedicated transfer queue, overlapped via a timeline semaphore; 0 keeps the single-queue rail.
DASLLAMA_VK_IMPORT	flag	on	Stream mirrors import the mapped .dlim (VK_EXT_external_memory_host) instead of pinned copies; =0 restores the copy path.
DASLLAMA_TRIM	flag	off	Serve from P3-trimmed vulkan images (big CPU weight families dropped; folded into the flavor identity).
DASLLAMA_VK_MEMPRIO	flag	on	Tag allocations high-priority (VK_EXT_memory_priority) so the driver demotes desktop memory, not ours.
DASLLAMA_VK_FA	flag	on	Vulkan flash attention: the decode fa kernel pick AND the cm2 prefill fa tile; 0 falls back to the chunked/scalar paths.
DASLLAMA_VK_REBAR	flag	on	Use a ReBAR device-local host-visible heap when one larger than 1GB is present.
DASLLAMA_VK_KV32	number	0	Arm the resident driver with f32 KV mirrors instead of the f16 default (A/B instrument; only sessions of the armed codec are served).
DASLLAMA_CM2_TILE	number	0	cm2 prefill tile pick: 0 = occupancy heuristic, 128 = force the m tile, 256 = force the l tile (A/B instrument).
DASLLAMA_CM2_SPLITK	number	0	cm2 split-k: 0 = occupancy heuristic, 1 = off, N = force N k-chunks (A/B instrument; shrinks if N strands an empty tail).
DASLLAMA_VK_SPV_OVERRIDE	path	unset	Directory of .spv files served instead of the emitted words at pipeline creation (offline spirv-opt / hand-patched A/B instrument).
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.

11.5. MoltenVK (macOS)

MoltenVK’s own configuration - listed because the vulkan tier arms it on Apple.

Variable	Type	Default	Effect
MVK_CONFIG_USE_METAL_ARGUMENT_BUFFERS	flag	unset (tier forces 0)	MoltenVK’s own knob. Its argument-buffers default miscompiles the batch tile kernels (stores never land, silently); the tier forces discrete bindings when this is unset.

11.6. 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_STRIPS	number	d/256, max 8	Strip count for the f32 sgemm lane; 0 keeps the shape-derived default.
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.

11.7. 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	auto-resolved from the models dir	Model used by the tuner’s confirm gate (FULL path, not a bare filename). Unset: the gate auto-resolves from the models dir — the preferred confirm carrier, else the largest present q8 gguf; the fallback pins only when the box has no q8 model at all.
DASLLAMA_BATCH_CHUNKS	text	unset	Override the batched-dispatch chunk count in the 1-core GEMM probe.
DASLLAMA_BATCH_GRID_2D	number	unset	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.

11.8. Benchmarks

Variable	Type	Default	Effect
DASLLAMA_ALLOW_UNTUNED	flag	off	Let a bench cell measure on fallback/absent tune winners, and skip the auto-tune mint entirely (untuned kernels keep fallback stamps instead of paying the minutes-long tune). The gate exists because a stale sidecar silently downgrades every kernel and the whole board sandbags; only set for dev runs whose numbers are never published.
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	unset	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	text	unset	Dump generated MSL from the Metal labs instead of running it.
DASMETAL_LAB_ARMS	text	unset	Substring filter restricting which arms the Metal MoE lab runs.
DASMETAL_LAB_SHAPES	text	unset	Substring filter restricting which shapes the Metal GEMV/GEMM labs run.
DASMETAL_LAB_VARIANTS	text	unset	Substring filter restricting which kernel variants the Metal GEMV/GEMM labs run.
PROBE_PATH	path	_wcliff.bin	Scratch file the write-cliff probe writes, cwd-relative by default; point it at the drive under test.
PROBE_GB	number	50	Gigabytes the write-cliff probe writes before reporting.

11.9. Profiling and baselines

Variable	Type	Default	Effect
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.
DASLLAMA_GPU_NAME	text	probed	Override the GPU name recorded in a box 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	../whisper.cpp	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.
DASLLAMA_BASE_PYTHON	path	unset	Base CPython 3.10-3.12 for creating the ASR oracle venvs, when neither PATH names nor uv resolve one in range.
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.

11.10. 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.
TEMP	path	unset	Windows scratch-directory fallback when TMPDIR is unset (the test runner’s log dir).

11.11. 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.

11.12. Sidecar exchange

Overrides for the dasllama.io exchange client.

Variable	Type	Default	Effect
DASLLAMA_EXCHANGE_URL	text	unset	Sidecar exchange base URL override (tests, mirrors); unset = the baked-in dasllama.io.
DASLLAMA_EXCHANGE_ACCEPT	text	unset	One-shot exchange accept-policy override: verified

11.13. 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
HF_HOME	path	~/.cache/huggingface	Hugging Face hub root; fetch_models –convert resolves checkpoint blobs under <HF_HOME>/hub. Falls back to HOME’s default cache location when unset.
HOME	path	unset	Ambient platform variable; read only to derive the default Hugging Face cache when HF_HOME is unset.
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	2 on darwin (engine [init]), else 0	Worker affinity: 0 off, 1 ideal-processor hint, 2 hard mask — on darwin mode 2 is QoS classification (no pin API) and dasLLAMA defaults it on. 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.
JOBQUE_PROFILING	flag	off	Compile the jobque marker rail in (read at COMPILE time by daslib/build_const). Without it trace_tag/trace_marker erase from the program; decode_prof –trace refuses on a build without it.