# Ling-3.0-flash Q6_K Trial on Dankclaw

> **RETIRED 2026-08-17.** The `frank-large-ling` unit is disabled under the boot policy. `frank-default-large` now runs the Qwen3.8-27B PP head, not the Qwen3.6-27B config described in the (obsolete) switch-back section below.

This page records the Ling-3.0-flash trial that temporarily replaced
`frank-default-large` on Dankclaw. It replaces the Qwen3.6-27B service on
port 7770 under the same API alias.

## Status

- Service: `frank-large-ling` (systemd).
- Model: `inclusionAI/Ling-3.0-flash` Q6_K (MoE, ~118B total params).
- Runtime: llama.cpp **fork** `aetherbird/llama.cpp` branch
  `bailingmoe3-support` (commit `db4480bc8`, build b10411) at
  `/home/dank/llama.cpp-ling`. Stock llama.cpp cannot load the
  `bailingmoe3` architecture.
- Backend: `Vulkan0` (RADV) with AMD GTT.
- Spec: `draft-mtp` `n_max 3`. The MTP block is bundled in the Ling GGUF
  itself (block 42) - no separate drafter file.
- Context: 262144 total, 2 slots x 131072, batch 512 / ubatch 256.
- Measured: load ~45s, generation ~7.7 t/s (cold, 4k prompt) to ~36 t/s
  (tiny cached prompt). Concurrent streams both complete.

## Why Vulkan + GTT

The Strix Halo APU has 8 x 16 GB LPDDR5 modules = **128 GB physical
shared memory**. The firmware carves ~96 GiB as dedicated iGPU VRAM; the
kernel sees the remainder (~30 GiB, `MemTotal`). GRUB adds no memory
options (`iommu=pt` only).

The ROCm runtime reports 96 GiB VRAM. **Vulkan (RADV) reports a
111.2 GiB heap** (113910 MiB) because it can also reach system memory
through the GTT. For a model near 100 GiB, Vulkan is the only backend
with room. `--list-devices` shows the heap:

```
ROCm0:   AMD Radeon Graphics (98304 MiB)
Vulkan0: AMD Radeon Graphics (RADV STRIX_HALO) (113910 MiB)
```

## Memory Fit (Q6_K = 98.26 GiB)

| Item | Size |
| ---- | ---- |
| Vulkan heap (llama.cpp view) | ~111.2 GiB |
| Model Q6_K file | 98.26 GiB |
| Model + MTP + graphs in heap | ~98.7 GiB |
| Free heap after load | ~10 GiB |

Ling uses gated MLA and KDA attention. KV cache stays tiny: 256k total
context costs only ~2.5 GiB. This is why 256k context fits.

## Freeze Bug (2026-08-14) - Spec Path Deadlock

### Symptom

Under 2+ concurrent streams with speculative decoding, one stream hard-freezes
mid-generation (zero output for minutes; a deadlock, not slowness). Freeze
point varies (385-1588 tokens). Single streams never freeze.

### Isolated cause

- Not context exhaustion: `truncated = 0`, under 131072 ctx.
- Not batch (3072 and 8192 both froze) and not log verbosity (0 and 4 both).
- `parallel=2` + `draft-mtp,ngram-mod` -> freeze.  SPEC OFF -> no freeze.
- Culprit: the speculative-decode / context-checkpoint path in llama-server
  with multiple slots on the Vulkan backend. Known bug family: PR #24891,
  #24797 (server checkpoint fixes), #25144 (MTP draft crash), plus a
  ggml-vulkan hang-under-sustained-compute class.

### Resolution: SPEC OFF

`SPEC_TYPE=none`, `PARALLEL=2`.  All concurrent streams complete (EOS).
Speed cost: ~10-13 t/s under contention vs ~28-32 t/s single-stream with
MTP.  Fallback chain if spec-off regresses: A) `PARALLEL=1` keep MTP,
B) switch back to Qwen3.6-27B (frank-default-large, MTP n_max 3).

## Files

- `scripts/frank-large-ling.service` - systemd unit.
- `scripts/serve-ling-flash.sh` - serve script (fork binary, Vulkan,
  draft-mtp).
- `scripts/frank-default-large.ling.env` - tunables.

Passwordless management is installed:
`/usr/local/sbin/frank-restart-ling.sh` and `/etc/sudoers.d/frank-ling`.

## Switch Back (obsolete)

The switch-back commands below are obsolete. `frank-default-large` now
runs the Qwen3.8-27B pipeline-parallel head. To restore a Ling trial,
re-enable `frank-large-ling` from the repo unit
(`scripts/frank-large-ling.service`) and serve script
(`scripts/serve-ling-flash.sh`), then start it on a non-conflicting port.

## Caveats

- The `bailingmoe3` fork validates CPU and CUDA upstream. Vulkan was
  validated here (load + generation + concurrent streams) on 2026-08-14.
- The tokenizer logs `special_eos_id is not in special_eog_ids` at load.
  It is a warning; generation stops correctly at EOS.
- Physical RAM pressure stays low because the model fits in the UMA
  carve-out. Generation speed on this APU is below the Qwen3.6-27B MTP
  config (~7.7 vs ~15-19 t/s at 4k).
- The heap is effectively full (98.7 of 111.2 GiB). Do not raise the
  context much without checking `--list-devices` free MiB.

## See Also

- [[frank-default-large-benchmark]]
- [[DFlash DSpark Speculative Decoding]]
- [[deployment]]