Benchmarking

SAPL Node includes two commands for measuring PDP performance: sapl benchmark for embedded evaluation throughput, and sapl loadtest for remote server load testing.

Embedded Benchmark

The benchmark command measures policy evaluation throughput and latency of an embedded PDP using a built-in timing harness. It runs entirely in-process without a server.

sapl benchmark --rbac -o ./results

The --rbac flag uses a built-in RBAC scenario that requires no policy files. Alternatively, point at your own policies:

sapl benchmark --dir ./policies -s '"alice"' -a '"read"' -r '"doc"' -o ./results

Options

Option	Default	Description
--rbac		Use built-in RBAC benchmark (no files needed)
--dir, --bundle	~/.sapl/	Policy source
-s, -a, -r		Subscription components (JSON values)
-b, --benchmark	decideOnceBlocking	Method: decideOnceBlocking, decideStreamFirst, noOp
-t, --threads	1	Concurrent benchmark threads
--warmup-iterations	3	Number of warmup iterations
--warmup-time	45	Seconds per warmup iteration
--measurement-iterations	5	Number of measurement iterations
--measurement-time	45	Seconds per measurement iteration
--latency	true	Run a latency measurement pass after throughput
-o, --output		Output directory for Markdown, CSV, and JSON reports
--machine-readable	false	Output single-line parseable results for scripts

For rigorous benchmarks with JIT isolation across forked JVMs, convergence checking, and advanced JVM tuning, use the sapl-benchmark-sapl4 module instead. The embedded sapl benchmark command is designed for quick assessments.

Remote Load Test

The loadtest command measures throughput and per-request latency of a running SAPL Node server. It supports both HTTP/JSON and RSocket/protobuf transports.

HTTP

sapl loadtest --url http://localhost:8443 -s '"alice"' -a '"read"' -r '"doc"'

RSocket

sapl loadtest --rsocket --host localhost --port 7000 -s '"alice"' -a '"read"' -r '"doc"'

Options

Option	Default	Description
--url	http://localhost:8443	HTTP server URL
--rsocket		Use RSocket/protobuf transport instead of HTTP
--host	localhost	RSocket server host
--port	7000	RSocket server port
--socket-path		Unix domain socket path (alternative to host/port)
--concurrency	64	Concurrent in-flight requests (HTTP)
--connections	8	Number of TCP connections (RSocket)
--vt-per-connection	512	Virtual threads per RSocket connection
--rate	0	Target req/s (0 = saturation mode)
--warmup-seconds	5	Warmup duration
--measurement-seconds	10	Measurement duration
-o, --output		Output directory for reports
--label		Label for the report
--machine-readable	false	Output single-line parseable results for scripts

Saturation vs Paced Mode

By default (--rate 0), the load generator sends requests as fast as possible (saturation mode) to find the server’s throughput ceiling. When --rate is set, it sends requests at a fixed rate with coordinated omission correction for accurate latency measurement under controlled load.

RSocket Connection Tuning

RSocket mode distributes load across multiple TCP connections. Each connection runs a configurable number of virtual threads. The total concurrency is --connections multiplied by --vt-per-connection. For example, 8 connections with 512 virtual threads each gives 4096 concurrent in-flight requests.

sapl loadtest --rsocket --connections 8 --vt-per-connection 512 -s '"alice"' -a '"read"' -r '"doc"'

For the full option reference, see the CLI Reference.