profile-performance-certus-api-bench

The purpose of this skill is to capture a snapshot of performance by running certus-server (release build) and certus-api-bench.py.

Create the output directory from the output-dir argument, for example: mkdir -p <output-dir> Write PROFILE.md to <output-dir>/PROFILE.md.

Collect data for combinations of the following parameters:

1. SSD device count D (1..N), where N is the number of detected SSD PCI devices. Detect available SSDs via lspci -d <vendor>:<device> or equivalent, sort PCI addresses lexicographically, and use the first D addresses. Pass each selected device as repeated flags: --device-pci <PCI1> --device-pci <PCI2> ... --device-pci <PCID> If D > N, skip that combination and record SKIPPED: requested D > available N in PROFILE.md.
2. Memory tier size: 4GB, 8GB, 16GB with --memory-tier-size <bytes> (use bytes, e.g. 4294967296).
3. Number of clients: 1, 2, 4, 8, 16 with certus-api-bench --clients <count>.
4. Cache block size: 1MB, 2MB, 4MB, 5MB with certus-api-bench --block-size <bytes> (use bytes, e.g. 1048576).
5. Batch size: 8, 16, 32, 64 with certus-api-bench --batch-size <count>.
6. Objects per lookup batch: 16, 32 with certus-api-bench --num-objects <count>.
7. Iterations: 10, 20, 50 with certus-api-bench --iterations <count>.

Other requirements:

• Run certus-server with --format.
• Run a full factorial Cartesian product across the listed values. If the total number of combinations exceeds 200, sample uniformly at random to 200 combinations and document the strategy in PROFILE.md.
• Execute experiments sequentially by default, restarting certus-server between combinations and avoiding parallel runs.
• For each combination: a. Stop any running certus-server. b. Start certus-server with the selected --device-pci flags, --memory-tier-size, and --format. c. Retry startup up to 3 times with a 5s delay if it fails. If startup still fails, record the combination as FAILED in PROFILE.md with stderr and continue. d. After a healthy start, run a 1-iteration warm-up of certus-api-bench before measurement. e. Run the measured iterations. f. If certus-api-bench exits non-zero, capture stdout/stderr to <output-dir>/logs/<run-name>.log, mark the run as ERROR in PROFILE.md, retry once, and if still failing continue to the next combination. g. Stop certus-server and collect logs.
• For each run write raw JSON to: <output-dir>/results/devicecount-<D>_mem-<M>_clients-<C>_bs-<B>_batch-<X>_objs-<O>_iter-<I>.json and a human-readable log to: <output-dir>/logs/devicecount-<D>_mem-<M>_clients-<C>_bs-<B>_batch-<X>_objs-<O>_iter-<I>.log

Run combinatorial experiments and build a result table in <output-dir>/PROFILE.md.

PROFILE.md must include a table with columns: device_count | pci_list | memory_tier_size_bytes | clients | block_size_bytes | batch_size | num_objects | iterations | throughput_GB_per_sec (populate) | throughput_GB_per_sec (hot lookup) | throughput_GB_per_sec (cold lookup) | notes

Include raw output file links and log links in PROFILE.md.

Summarize the data and identify performance anomalies.

Create a plot with Y-axis throughput, X-axis device_count for:

1. Populate
2. Lookup (hot)
3. Lookup (cold)

Save plot in output directory.