perftok 0.1.1

Lightweight benchmarking tool for OpenAI-compatible LLM endpoints

perftok

Lightweight benchmarking tool for OpenAI-compatible LLM endpoints.

perftok gives you the same metrics as aiperf (TTFT, ITL, throughput, latency percentiles) with a simple pip-installable CLI — no ZMQ services, no Ray dependency, no special binaries.

Installation

pip install perftok

Or from source:

git clone https://github.com/timsleeper/perftok.git
cd perftok
pip install -e ".[dev]"

Requires Python 3.10+.

Quick Start

# Benchmark a local vLLM / TGI / Ollama endpoint
perftok \
  --url http://localhost:8000 \
  --num-requests 100 \
  --concurrency 10

# Specify model explicitly
perftok \
  --model meta-llama/Meta-Llama-3-8B-Instruct \
  --url http://localhost:8000 \
  --num-requests 100 \
  --concurrency 10

# Hosted endpoint with API key
perftok \
  --url https://api.example.com \
  --api-key $API_KEY \
  --num-requests 50 \
  --concurrency 5 \
  --output-format json \
  --output-file results.json

If --model is omitted, perftok queries /v1/models and prompts you to confirm.

CLI Options

perftok [OPTIONS]

  --model TEXT                    Model name (auto-discovered if omitted)
  --url TEXT                      Base URL of the endpoint [required]
  --api-key TEXT                  API key (or set API_KEY env var)
  --concurrency INTEGER           Max concurrent requests [default: 1]
  --num-requests INTEGER          Total number of requests [default: 1]
  --mean-input-tokens INTEGER     Mean input prompt tokens [default: 550]
  --stddev-input-tokens INTEGER   Stddev of input tokens [default: 150]
  --mean-output-tokens INTEGER    Mean output tokens [default: 150]
  --stddev-output-tokens INTEGER  Stddev of output tokens [default: 10]
  --timeout INTEGER               Request timeout in seconds [default: 300]
  --streaming / --no-streaming    Use streaming SSE responses [default: streaming]
  --output-format [table|json|csv]  Output format [default: table]
  --output-file TEXT              Write results to file

Metrics

Metric	Unit	Aggregation
TTFT (Time to First Token)	ms	p50 / p75 / p90 / p95 / p99 / min / max / mean / stddev
ITL (Inter-Token Latency)	ms	same
E2E Request Latency	ms	same
Output Token Throughput	tokens/s	system-wide aggregate
Output Throughput Per Request	tokens/s	per-request with percentiles
Request Throughput	req/s	aggregate
Error Rate	%	aggregate

Output Formats

Table (default) — Rich-formatted summary printed to the terminal.

JSON — Full report as structured JSON, suitable for programmatic consumption.

CSV — Flattened single-row CSV with all metrics, handy for appending to spreadsheets.

Use --output-file to write results to disk in any format.

TLS/SSL

If TLS certificate verification fails, perftok exits with a clear error message. Pass --insecure to bypass verification — common with local inference servers behind self-signed certs.

Architecture

• Concurrency: asyncio + aiohttp + Semaphore — no threads, no Ray, no ZMQ
• Token counting: tiktoken (cl100k_base) for exact prompt-length targeting
• Models: Pydantic v2 for config validation and report serialization
• CLI: Click single-command interface
• Output: Rich tables, JSON, CSV

Development

pip install -e ".[dev]"
pytest -v              # 89 tests
ruff check src/ tests/ # lint

License

Apache 2.0