DwarfStar (antirez/ds4) as a backend: 1bit serve --device ds4 - #111

…erver directly (#475)

* serve --print-backend: one hop from Lemonade for GGUF models

A chat request through Lemonade went lemond -> 1bit serve -> llama-server: two HTTP hops and
three processes. `1bit serve ... --print-backend` makes every check serve makes before a load
(architecture, memory admission, placement flags, recipes, the HRX environment) and prints the
llama-server it would start, on the port the caller passed, as one JSON line, then exits:
0 printed, 3 does not fit, 5 the route needs serve in the request path (NPU directory or
--device npu, onnx, ds4, --pm, --laya, --embed/--rerank). Lemonade's onebit recipe (fork branch
1bit/one-hop) starts that llama-server itself and forwards to it directly.

The plan adds --alias (Lemonade's name) and, for chat models, --cache-reuse 256 unless a recipe
set it; env lists only variables the caller's environment does not already set, so a user value
still wins as under serve.

What serve did on the request path moves into the backend:
- llama.cpp pin 680933de1 (fork branch 1bit/one-hop, on #111): /health answers 503 while the
  main loop is stalled with work queued, so Lemonade's BackendWatchdog probe resets a hung GPU,
  and llama-server exits on a lost GPU (serve's #466 signal);
- --strict-device stays GGML_HRX_STRICT in the backend.

third_party/lemonade pins the fork's 1bit/one-hop commit 23972095. registry/architectures.json
regenerated for the new llama.cpp pin.

Test: tests/print_backend.sh (ctest print_backend, no GPU): the JSON plan, port, alias,
--cache-reuse, ctx, the embedding role, exit 5 for NPU/--pm/--embed, exit 3 for a model that does
not fit, nothing started.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* docs/serve.md: one hop measured on Strix Halo; tools/onehop_bench.py

tools/onehop_bench.py starts a private lemond (own cache/config dirs and port), loads one onebit
model on HRX and measures load time, /tokenize and a 1-token chat via Lemonade and direct, time to
first token, and (one-hop arm) a pinned reload beside a second model and an unload + load.

Qwen3-4B-Instruct-2507 Q4_K_M on hrx, six rounds per arm, same llama-server for both: the serve
hop cost about 0.2 ms a request (/tokenize 0.53-0.64 ms -> 0.36-0.39 ms via Lemonade, 0.11-0.15 ms
direct); load 1.62 s -> 1.35-1.56 s; chat and time to first token unchanged within noise. A pinned
reload keeps the same llama-server and its warm program cache (seen length 106-119 ms); an unload +
load starts cold (228-236 ms).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* Pin llama.cpp 3c24f910f (fork #112) and lemonade 80064ba7 (fork #15): the squash merges of the one-hop branches

Same trees as 680933de1 and 23972095, which the hw-gate run on this PR tested.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* registry: regenerated at llama.cpp 3c24f910f

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

---------

Co-authored-by: bong-water-water-bong <bong-water-water-bong@1bit.gg>
Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>