infra/assets/ai-optimizer/CRON_JOB_DRAFT.md

AI Model Optimization Cron Job

Goal: Find optimal configurations for maximum context size with full hardware utilization.

Hardware:

• 2× AMD MI50 GPUs (32GB VRAM each, 64GB total)
• 128GB system RAM
• ROCm: HSA_OVERRIDE_GFX_VERSION=9.0.6, HIP_VISIBLE_DEVICES=0,1

---

Model Queue

GPU-Optimized (Coding - prioritize speed + context on GPU)

1. devstral-small-2:24b - Best coding model
2. qwen2.5-coder:32b - Strong coder, fits on GPU+offload
3. codellama:34b-instruct - Legacy but solid

RAM-Optimized (Knowledge - prioritize max context, accept slower)

1. qwen2.5:72b - Best knowledge, needs heavy offload
2. nemotron-3-nano:30b - Good general knowledge
3. mixtral:8x7b-instruct - MoE, efficient for knowledge

---

Optimization Strategy

Two separate tracks:

Track A: GPU-Focused (Coding)

Baseline: num_ctx=32768, num_gpu=99, flash_attn=true
Steps:
1. Increase context: 32k → 65k → 98k → 131k → 163k
2. At each step, verify VRAM usage < 60GB (leave headroom)
3. If OOM: reduce num_gpu until stable, record best
4. Measure tokens/sec - if < 5 tok/s, consider context too high

Track B: RAM-Focused (Knowledge)

Baseline: num_ctx=65536, num_gpu=50, flash_attn=true
Steps:
1. Increase context: 65k → 131k → 200k → 262k → 327k
2. Allow heavy RAM offload (system RAM up to 100GB)
3. If OOM: reduce context or num_gpu
4. Speed less critical - focus on max stable context

---

Backend-Specific Configs

Ollama (Modelfile parameters)

PARAMETER num_ctx <value>
PARAMETER num_gpu <layers>
PARAMETER flash_attn true/false
PARAMETER num_predict 4096
PARAMETER num_keep 1024
PARAMETER repeat_penalty 1.1

Llama.cpp (CLI flags)

--ctx-size <value>
--n-gpu-layers <layers>
--flash-attn on/off
--n-predict 4096
--batch-size 4096
--ubatch-size 512
--cache-type-k f16
--cache-type-v f16
--split-mode layer
--no-mmap

---

Host Test Instructions

The cron runs inside the hermes container. Some tests require host access:

1. VRAM Monitoring (HOST)

# Run on host to check VRAM usage during/after benchmark
sudo rocm-smi --showmeminfo vram

# Or via docker exec if rocm-smi available in container
docker exec --privileged ollama rocm-smi --showmeminfo vram

2. Running Ollama Benchmarks (CONTAINER)

# Pull model
docker exec ollama ollama pull <model>

# Create custom modelfile
docker exec ollama bash -c 'cat <<EOF > /root/.ollama/test.modelfile
FROM <model>
PARAMETER num_ctx 65536
PARAMETER num_gpu 99
PARAMETER flash_attn true
EOF'

# Create model from modelfile
docker exec ollama ollama create test-model -f /root/.ollama/test.modelfile

# Run benchmark (warm model first)
docker exec ollama ollama run test-model "Write a Python async context manager with exponential backoff"

# Cleanup
docker exec ollama ollama rm test-model

3. Running Llama.cpp Benchmarks (CONTAINER - needs llama.cpp container)

# Uncomment llama_cpp_devstral in compose.yml first
# Then rebuild: sudo nh os switch --flake .#lazyworkhorse

# Test via HTTP API
curl http://localhost:8300/v1/completions \
  -H "Content-Type: application/json" \
  -d '{
    "model": "devstral-2-small-llama_cpp",
    "prompt": "Write a Python function",
    "max_tokens": 100
  }'

4. Deploying Changes (HOST via ai-worker)

# After optimization, commit results
cd /home/ai-worker/infra
git add assets/ai-optimizer/
git commit -m "ai-optimizer: new best config for <model>"
git push

# If config changes needed in ollama_init_custom_models.nix:
# 1. Edit the file
# 2. nixpkgs-fmt .
# 3. Show diff to user
# 4. Wait for confirmation
# 5. sudo nh os switch --flake .#lazyworkhorse

5. Accessing Host from Hermes Container

# SSH to host as ai-worker (key should be mounted)
ssh -i /path/to/key ai-worker@host.docker.internal

# Or via docker socket if mounted
# (not recommended for security)

---

Benchmark Prompts

Coding (Track A)

"Write a Python async context manager that retries a function with exponential backoff, max 5 retries, and logs each attempt using structlog. Include type hints and error handling."

Knowledge (Track B)

"Explain the complete memory hierarchy in modern GPUs, from registers through L1/L2 caches to VRAM, and how data moves between them during matrix multiplication. Include bandwidth considerations for each level."

Measurement

• Tokens per second (generation speed)
• Time to first token (latency)
• VRAM usage (via rocm-smi)
• System RAM usage (via free -h)
• Context success (did it complete without OOM?)

---

State File Structure

/opt/data/infra/assets/ai-optimizer/state.json

{
  "track": "gpu",
  "current_model": "devstral-small-2:24b",
  "model_index": 0,
  "phase": "context_scaling",
  "backend": "ollama",
  "current_config": {
    "num_ctx": 65536,
    "num_gpu": 99,
    "flash_attn": true
  },
  "best_configs": {
    "gpu": {
      "devstral-small-2:24b": {
        "backend": "ollama",
        "num_ctx": 131072,
        "num_gpu": 99,
        "flash_attn": true,
        "tokens_per_sec": 12.5,
        "vram_used_gb": 58.2,
        "tested_at": "2026-04-28T17:00:00Z"
      }
    },
    "ram": {}
  },
  "completed_models": [],
  "gpu_queue": ["devstral-small-2:24b", "qwen2.5-coder:32b", "codellama:34b-instruct"],
  "ram_queue": ["qwen2.5:72b", "nemotron-3-nano:30b", "mixtral:8x7b-instruct"]
}

---

Results CSV

/opt/data/infra/assets/ai-optimizer/results.csv

timestamp,track,model,backend,phase,num_ctx,num_gpu,flash_attn,tokens_per_sec,vram_gb,ram_gb,status,is_best
2026-04-28T17:00:00Z,gpu,devstral-small-2:24b,ollama,context_scaling,65536,99,true,15.2,52.1,18.4,success,false

---

Cron Job Flow

1. Read state.json
2. If both queues empty → STOP (all models tested)
3. Select next model from current track queue
4. Pull model if needed (docker exec ollama ollama pull)
5. Create Modelfile / llama.cpp config with current test params
6. Run benchmark (both prompts)
7. Measure: tokens/sec, VRAM (rocm-smi), RAM (free -h)
8. If successful:
   - Increase context (next step)
   - Update current_config in state
9. If OOM/error:
   - Record last good config as best_configs[track][model]
   - Move to next model in queue
10. Update state.json
11. Append to results.csv
12. Git commit + push to /opt/data/infra
13. Send Matrix notification if available, else silent

---

Matrix Notification (Optional)

# If matrix credentials available in environment
if os.getenv("MATRIX_HOME_SERVER") and os.getenv("MATRIX_ACCESS_TOKEN"):
    # Send completion notification
    # Room: !ai-optimizer:lazyworkhorse.net (or similar)
    pass
# Else: silent, just commit

---

Files to Create

/opt/data/infra/assets/ai-optimizer/
├── state.json           # Current progress
├── results.csv          # All test results
├── best_configs.json    # Final best configs (human-readable)
└── CRON_JOB_DRAFT.md    # This file

---

Notes

• No num_parallel: Removed to avoid limiting other settings
• Two tracks: GPU (coding/speed) vs RAM (knowledge/context)
• Both backends: Test ollama first, then llama.cpp if available
• Host tests: rocm-smi must run on host or privileged container
• Deploy: ai-worker has sudo for nh/nixos-rebuild, must ask user first