The first #10485 fix (#10494) made the Blackwell physical-batch boost
per-device/context-aware, which neutralized the big compute-buffer OOM, but
the reporter's 2x16 GiB consumer Blackwell still OOM'd. Tracing the post-fix
log: the model now loads its weights, builds the main context and warms up
fine, and dies only on the *last* allocation — the MTP draft context's 800 MiB
KV cache on the tighter device.
#10411 changed only two defaults: the physical batch (now gated) and a
VRAM-scaled parallel-slot count. The KV cache is unified (n_ctx_seq == full
context proves slots share the budget, so parallel doesn't multiply KV), but
n_seq_max=4 still adds per-slot compute-graph / context-checkpoint / output
scratch. On a device packed ~99% by a 27B model spanning both cards, that
overhead is the few-hundred-MiB straw — which is why reverting #10411 (and only
#10411) restores a working load.
Gate the parallel-slot default on the same per-device headroom predicate as the
batch boost: when a large context already fills a single card
(largeContextForDevice), keep n_parallel=1. A user running one big-context model
that barely fits across two consumer GPUs is not serving four concurrent
tenants. Small contexts and large unified-memory devices (GB10) keep full
concurrency. Applied on both the single-host path and the distributed router.
Also make the auto-tuning visible and reversible (the debugging here needed
DEBUG logs and a git bisect):
- Log the effective performance-relevant runtime options at INFO once per
model load ("effective runtime tuning …": context, n_batch, n_gpu_layers,
parallel, flash_attention, f16) so an admin can see what will run and pin or
override any value in the model YAML.
- LOCALAI_DISABLE_HARDWARE_DEFAULTS=true skips the hardware auto-tuning
entirely (mirrors LOCALAI_DISABLE_GUESSING) for stock llama.cpp behavior.
Assisted-by: Claude:opus-4.8 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
Co-authored-by: Ettore Di Giacinto <mudler@localai.io>
The hardware-tuned defaults from #10411 were measured on a GB10 / DGX Spark
(128 GiB unified memory) and over-provisioned multi-GPU consumer Blackwell
(e.g. 2x16 GiB RTX 50-series) into CUDA OOM during model init:
- The Blackwell physical batch (512 -> 2048) sets both n_batch and n_ubatch.
The compute buffer scales ~n_ubatch * n_ctx and is allocated PER DEVICE
(it can't be split across GPUs), so a large context turns ub2048 into
multi-GiB of scratch that must fit one 16 GiB card.
- The VRAM-scaled parallel-slot default tiered off TotalAvailableVRAM(),
which SUMS all GPUs (2x16 -> "32 GiB" -> 8 slots), but the allocations
are per-device.
Make both decisions per-device and context-aware:
- xsysinfo.MinPerGPUVRAM() reports the smallest device's VRAM; localGPU()
uses it so the parallel tier and batch guard reason about one card.
- PhysicalBatchForContext(gpu, ctx) raises the batch only when the extra
compute buffer fits VRAM/4 at this model's context (16 GiB crosses over
~174k ctx, 32 GiB ~349k; GB10 reports system RAM so it still clears it).
- Apply hardware defaults AFTER runBackendHooks in SetDefaults so the
GGUF-guessed context is resolved before the batch decision.
- The distributed router gates the node batch the same way.
Unified-memory devices (GB10, Apple) report system RAM as their single
device's VRAM, so they keep the prefill win.
Assisted-by: Claude:opus-4.8 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
Co-authored-by: Ettore Di Giacinto <mudler@localai.io>
* feat(config): node-aware hardware defaults — larger physical batch on Blackwell
A larger physical batch (n_batch/n_ubatch) materially lifts MoE prefill on
NVIDIA Blackwell consumer GPUs (sm_120/121, incl. GB10 / DGX Spark) — measured
on a GB10 with Qwen3-Coder-30B-A3B, the prefill ceiling rises (ub512 ~2994 ->
ub2048 ~3316 t/s) and saturates around 2048.
The heuristic lives in core/config alongside the other config overriders
(ApplyInferenceDefaults, guessDefaultsFromFile/NGPULayers) — they all fill the
ModelConfig from heuristics, so hardware tuning is the same domain and stays in
one place. It is parameterized on a GPU descriptor (not direct detection) so it
works in both deployment shapes:
- Single host: SetDefaults applies it with the LocalGPU.
- Distributed: only the worker sees the GPU, so the worker reports its compute
capability on registration (gpu_compute_capability -> BackendNode), and the
router re-applies the SAME core/config heuristic for the SELECTED node before
loading — fixing the case where the frontend has no GPU at all.
Explicit `batch:` always wins (only managed default values are touched).
xsysinfo gains NVIDIAComputeCapability() (detection only); all interpretation
lives in core/config. Tests: core/config, pkg/xsysinfo, core/services/nodes.
Assisted-by: Claude:opus-4.8 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
* test(config): injectable local-GPU seam + single-instance coverage
Make local GPU detection an injectable package var (localGPU) so the
single-instance path (SetDefaults -> ApplyHardwareDefaults) is deterministically
testable without a real GPU, mirroring the distributed override's coverage.
Adds specs asserting SetDefaults sets the Blackwell physical batch, leaves it
unset on non-Blackwell, and never overrides an explicit batch.
Assisted-by: Claude:opus-4.8 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
* feat(config): default concurrent serving (n_parallel) by GPU VRAM
The llama.cpp backend defaults n_parallel=1, which serializes multi-user requests
and leaves continuous batching off (it auto-enables only at n_parallel>1). Fold a
VRAM-scaled parallel-slot default into the hardware-config path so multi-user
serving works out of the box: >=32GiB->8, >=8GiB->4, >=4GiB->2, else unchanged.
With the backend's unified KV the slots SHARE the context budget, so this adds
concurrency without multiplying KV memory. Explicit parallel/n_parallel always
wins. EnsureParallelOption is shared by the single-host path (ApplyHardwareDefaults
with the local GPU) and the distributed router (per selected node's reported VRAM,
since the frontend may have no GPU). LocalGPU now also reports VRAM.
Assisted-by: Claude:opus-4.8 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
---------
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
Co-authored-by: Ettore Di Giacinto <mudler@localai.io>
