.gitea/workflows/deploy.yaml

@@ -88,8 +88,9 @@ jobs:
           # so the firewalld rich rule admits it. lair/quantus's SCRAPE_MINERS
           # must list it so Prometheus scrapes it.
           #
-          # Mainnet call 2026-09-09 (quantus/miner#1): all three hosts mine;
-          # neuron (cortex inference) is disabled on each of them.
+          # Mainnet call 2026-09-09 (quantus/miner#1): all three hosts mine
+          # when neuron (helexa inference) is not enabled on them. A host with
+          # neuron enabled keeps its miner files current but is not started.
           # `kernel` is the kernel id validate expects on the per-device metric:
           # cuda (engine-cuda, #3) on every NVIDIA host once the build carries
           # the fat binary; u64 would mean the miner silently fell back to wgpu.
@@ -263,6 +264,20 @@ jobs:
             run "sudo firewall-cmd --zone=$zone --add-rich-rule='$mrich'"
           fi
 
+          # A host whose neuron.service is enabled is serving LLM inference.
+          # neuron conflicts with the miner (lair/quantus drop-in), so enabling
+          # or starting the miner here would stop inference mid-request and put
+          # the host back to mining behind the operator's back. Ship the files,
+          # reload so the next deliberate start sees them, and leave it there.
+          # Switching a host is `systemctl disable --now neuron && systemctl
+          # enable --now quantus-miner`, done on purpose.
+          if run systemctl is-enabled --quiet neuron.service; then
+            run sudo systemctl daemon-reload
+            echo "neuron.service is enabled on ${{ matrix.host }}: inference host, miner left stopped"
+            echo "restarted=0" >> "$GITHUB_OUTPUT"
+            exit 0
+          fi
+
           run sudo systemctl enable quantus-miner.service   # idempotent
           if [ "$RESTART" = 1 ]; then
             echo "changes applied — restarting"
@@ -284,6 +299,14 @@ jobs:
           run() { ssh $SSHOPTS gitea_ci@"${{ matrix.host }}" "$@"; }
           fail=0
 
+          # Deploy leaves the miner stopped on an inference host (see above);
+          # there is nothing to validate there, and failing would make every
+          # miner deploy red for as long as the host serves.
+          if run systemctl is-enabled --quiet neuron.service; then
+            echo "neuron.service is enabled on ${{ matrix.host }}: inference host, miner not expected to run"
+            exit 0
+          fi
+
           echo "--- unit (${{ matrix.host }} -> ${{ matrix.node }}) ---"
           run systemctl is-active quantus-miner.service
 

crates/bench-harness/bench-on-host.sh

@@ -22,10 +22,15 @@ fi
 
 echo "--- host ---"
 hostname -f
-limit=$(nvidia-smi --query-gpu=power.limit --format=csv,noheader,nounits | awk 'NR==1{printf "%d", $1}')
-echo "power limit: ${limit} W"
 "$BIN" --version
 
+# A host serving inference is not a bench host, even when idle: the window
+# locks the memory clock, which would cripple any request that lands in it.
+if systemctl is-active --quiet neuron.service; then
+  echo "neuron.service is active on this host; refusing to measure" >&2
+  exit 1
+fi
+
 echo "--- pause miner ---"
 was_active=0
 if systemctl is-active --quiet quantus-miner.service; then
@@ -37,8 +42,12 @@ fi
 resume() {
   if [ "$was_active" = 1 ]; then
     echo "--- resume miner ---"
+    # Its ExecStartPre applies the miner profile again.
     sudo systemctl start quantus-miner.service
     systemctl is-active quantus-miner.service
+  else
+    echo "--- restore default GPU profile ---"
+    sudo /usr/local/bin/nvidia-power-limit.sh default
   fi
 }
 trap resume EXIT
@@ -53,6 +62,14 @@ if [ "$util" -gt 5 ]; then
   exit 1
 fi
 
+# Stopping the miner reset the card to its default profile (ExecStopPost).
+# Measure under the profile the miner actually runs with, and read the limit
+# the harness asserts only after applying it.
+echo "--- apply miner GPU profile ---"
+sudo /usr/local/bin/nvidia-power-limit.sh miner
+limit=$(nvidia-smi --query-gpu=power.limit --format=csv,noheader,nounits | awk 'NR==1{printf "%d", $1}')
+echo "power limit: ${limit} W"
+
 echo "--- measure ---"
 cd "$DIR"
 RUST_LOG=info "$BIN" \

deploy/README.md

@@ -37,6 +37,18 @@ deploy on every run. Nothing secret lives here.
   advances and `miner_gpu_devices` matches the matrix.
 - **Binaries must be built on `cuda-13.0`** (Fedora 43, like the hosts). The
   `rust` runner is Fedora 44; its binaries fail with `GLIBC_2.43 not found`.
+- **The GPU profile lives and dies with the unit.** `quantus-miner.service`
+  applies the power limit and 810 MHz memory lock in `ExecStartPre` and resets
+  to driver defaults in `ExecStopPost`, via `nvidia-power-limit.sh` from
+  lair/quantus. The lock cuts LLM inference to a sixth of its speed with nothing
+  reporting as throttled, so it must not outlive the miner. Stopping the unit
+  therefore also resets the clocks — the benchmark re-applies the profile for
+  its window.
+- **An inference host is left alone.** When `neuron.service` is enabled on a
+  host, the deploy ships the miner's files but does not enable or start it, and
+  validate passes without checking hashing. neuron conflicts with the miner, so
+  starting it would stop inference. Switch hosts deliberately:
+  `systemctl disable --now neuron && systemctl enable --now quantus-miner`.
 - **A benchmark (`bench.yaml`) stops the miner on its host.** A deploy landing
   on the same host during a measurement would find the unit down and start it
   mid-window. Both are serialised only by not running them together.

deploy/infra-setup.sh

@@ -110,6 +110,11 @@ gitea_ci ALL=(root) NOPASSWD: /usr/bin/systemctl restart quantus-miner.service
 # mining for a measurement window and resume it afterwards.
 gitea_ci ALL=(root) NOPASSWD: /usr/bin/systemctl stop quantus-miner.service
 gitea_ci ALL=(root) NOPASSWD: /usr/bin/systemctl start quantus-miner.service
+# The benchmark measures under the miner's GPU profile, which stopping the unit
+# resets (its ExecStopPost). bench-on-host.sh re-applies it for the window and
+# restores whichever profile the host was in afterwards.
+gitea_ci ALL=(root) NOPASSWD: /usr/local/bin/nvidia-power-limit.sh miner
+gitea_ci ALL=(root) NOPASSWD: /usr/local/bin/nvidia-power-limit.sh default
 # Rollback: the deploy keeps the previous binary as .prev (cp) and restores it
 # with install when validate fails; cp back would hit "Text file busy" on the
 # running binary, install unlinks the destination first. Deploying from main means a bad commit reaches production;

deploy/quantus-miner.service

@@ -9,8 +9,13 @@
 #     finds no adapter, silently falling back to nothing.
 #
 # Poseidon2-over-Goldilocks is compute-bound in registers, not memory-bound, so
-# there is no tuning knob here worth more than the GPU power limit — which is a
-# host-level concern (nvidia-smi -pl), not a unit-file one.
+# the tuning that matters is the GPU profile: a lower power limit and memory
+# locked at 810 MHz (lair/quantus readme, "GPU memory clock"). That profile is
+# applied here, for the lifetime of this unit, and reset when it stops — it must
+# never outlive the miner, because the same lock cuts LLM inference on the host
+# to a sixth of its speed. The script and its per-host config
+# (/etc/default/nvidia-power-limit) are installed by lair/quantus's
+# infra-setup.sh; neuron.service on the same host conflicts with this unit.
 #
 # --cpu-workers 0 is deliberate: a current-gen desktop CPU contributes ~4 MH/s
 # next to a 4090's ~183 MH/s, for a couple hundred watts. Measured, not assumed.
@@ -37,6 +42,12 @@ ExecStart=/usr/local/bin/quantus-miner serve \
     --metrics-port 9900
 EnvironmentFile=/etc/quantus-miner/miner.env
 
+# '+' runs these as root; the miner itself stays unprivileged. ExecStopPost runs
+# however the service ends — stop, crash, failed start — so the lock cannot be
+# left behind by a miner that is no longer running.
+ExecStartPre=+/usr/local/bin/nvidia-power-limit.sh miner
+ExecStopPost=+/usr/local/bin/nvidia-power-limit.sh default
+
 # The node may be down, still syncing, or mid-redeploy; reconnecting is normal
 # operation, not an error condition.
 Restart=always