Profiling

Use profiling to diagnose CPU, memory, or contention issues in Smart Router. The router can send continuous profiles to Pyroscope, or expose Go's pprof server for one-off captures.

Continuous profiling (Pyroscope)

When you give the router a Pyroscope server address, it streams CPU, heap, goroutine, mutex, and block profiles to it continuously:

smartrouter config.yml --use-static-spec specs/ \
  --pyroscope-address http://pyroscope:4040 \
  --pyroscope-app-name smartrouter \
  --pyroscope-tags "instance=router-1,region=us-east"

Flag	Default	Purpose
--pyroscope-address	-	Pyroscope server URL. Profiling is off until this is set.
--pyroscope-app-name	smartrouter	Application name shown in Pyroscope.
--pyroscope-tags	-	Comma-separated key=value tags (instance, region, …) for filtering.
--pyroscope-mutex-profile-fraction	5	Mutex profile sampling rate (1 in N events).
--pyroscope-block-profile-rate	1	Block profile rate (ns; 1 records all blocking events).

Use the tags to tell replicas apart in the Pyroscope UI. When you run more than one router, set at least instance.

One-off profiling (pprof)

If you do not have a Pyroscope server, expose Go's standard pprof HTTP server and capture profiles when you need them:

smartrouter config.yml --use-static-spec specs/ --pprof-address localhost:6060

# capture a 30s CPU profile
go tool pprof http://localhost:6060/debug/pprof/profile?seconds=30

Bind it to localhost (or put it behind your network controls), because the pprof endpoints have no authentication.