Reading patch v2 1/2 verbatim: amd_iommu_enable_perfopt() rehoming needs the
device ALREADY on the identity domain and switches ATS/PRI/PASID/GCR3 off via
the skip_caps path. So an iGPU in identity mode still pays a 1:1 page walk plus
those four capabilities until PerfOpt exists -- iommu=pt recovers most of the
gap, PerfOpt the last part. The first pass claimed pt alone already avoids the
cost; that was wrong and is retracted here and in the posted issue comment
(edit 23).
Also re-keys frank-npu.md, which carried the dead law 'iommu=pt is not a middle
ground' as its retirement rationale: identity mode + SVA is exactly the revival
path (amdxdna binds its own IOPT_TYPE_SVA domain), and the cost is single-digit
percent on this silicon class. Procedure step 2 now demands a local off-vs-pt
measurement instead of inheriting the vendor's 13-16%, whose slow-arm boot line
our record never identified.
Records the 2026-10-18 answer to 'does a recent kernel change retire
amd_iommu=off': PerfOpt (iommu tree 2026-09-24, Linux 7.4) stops GPA->SPA
translation for the privileged iGPU while the IOMMU stays enabled for every
other device, the NPU included. Local census proves the fix is absent here
(zero perfopt symbols in System.map-7.0.0-38, archive caps at 7.0.0-38.38),
and the September 13-16% figure was translated-domain cost, not strict-flush
cost -- lazy DMA is the Ubuntu default, so iommu=pt already avoids it. The
corrected procedure therefore flips to iommu=pt now and treats PerfOpt as a
2-4% later bonus on this silicon class (Phoronix desktop arm), with the NPU
legal under identity mode because amdxdna binds its own SVA domain.
Re-keys the AGENTS.md key-lesson bullet; no host change.
The 2026-10-09 wire aliases become the service names everywhere:
systemd units, serve scripts, env files and FRANK_* variables,
deploy-plan/deploy-remote service keys, container names, Prometheus
job names + alert rules, Grafana dashboard queries, bats seams,
runbook filenames, homepage/AGENTS lore, and historical prose.
Rollback tags renamed in lockstep. Residue in the tree: zero.
Retired frank-medium/small/npu names are history and stay.
Known casualty: scripts/patches/*.patch context lines were rewritten;
those retired-era vLLM-fork patches no longer apply byte-exact.
frank-large moves from the kingjones30/ROCmFPX llama.cpp build to
peonist-ai/halogen-flash-server 0.5.8 serving Qwen3.8-Flash-Next (w4b
.hgn 115.55 GiB + quality overlay). Upstream measures this engine at
roughly 4x the prefill throughput of the llama.cpp family on the same
gfx1151 silicon, and prefill dominates any prompt with real context.
Shape: a rootless Quadlet container (dankclaw/frank-large/quadlet/),
engine on container loopback :8730 (never published), OpenAI front-end
:8731 published as host 7770, HALOGEN_MODEL_ID=frank-large so no client
renamed anything. Context 262144, KV pool 262144 positions (~7.2 GiB,
conservative for a shared 121 GiB host), 4 slots, host reserve 24,
vision tower on, weights pinned, all other flags at vendor defaults.
Weights are fetched by HALOGEN_DOWNLOAD on first start into a writable
/home/dank/models/halogen.
The llama.cpp era (unit, env, serve script) is staged in .AGENTTRASH/
rather than deleted; the STRIX payload and the ROCmFPX build stay on
disk as the rollback target. deploy_llm_large becomes a user-quadlet
handler: it retires the old ROOT unit (moving its checkout symlink into
the home trash, never rm) and gates the first start on the download
rather than reporting a failure for a fetch that is working exactly as
designed.
frank-npu is retired in the same change. The kernel cmdline moves from
iommu=pt to amd_iommu=off for the 13-16% of prefill upstream measured,
and that takes the XDNA2 NPU with it: without PASID/SVA the driver
cannot open /dev/accel/accel0 (err=-19). Its five dependent routes are
repointed (Hermes vision -> frank-large, Hermes title generation ->
frank-small, harness vision -> frank-large, tiny -> frank-small, task ->
frank-large:medium) and its provider blocks are removed from both the
harness config and Hermes's live config. Audio input leaves the fleet
with no replacement; image input survives on halogen's vision tower.
Docs: new halogen-flash-server runbook, new IOMMU decision record, and
frank-npu rewritten as a retirement record. AGENTS.md topology, runtime
sections, benchmarking policy (frank-large is a user unit now) and the
harness model-config section are corrected.
Frank