mo-service profiling flags

Starting in v3.0.11, mo-service accepts --block-profile-rate and --mutex-profile-fraction command-line flags that drive the Go runtime block and mutex profilers, and can be scraped via the /debug/pprof/block and /debug/pprof/mutex endpoints exposed by --debug-http.

mo-service is the executable that runs a MatrixOne node. Starting with v3.0.11, mo-service accepts two command-line flags that enable the Go runtime’s block and mutex profilers. They are intended for continuous profiling setups (for example, Pyroscope or go tool pprof collection against the /debug/pprof/block and /debug/pprof/mutex endpoints exposed by --debug-http).

Either flag can be disabled by passing 0.

Flags

Flag

Default

Effect

--block-profile-rate

5

Controls the fraction of goroutine blocking events that are reported in the block profile. Internally calls Go’s runtime.SetBlockProfileRate(rate). 0 disables the block profile. Recommended values: 100 for production, 1 for debugging.

--mutex-profile-fraction

100

Controls the fraction of mutex contention events that are reported in the mutex profile. Internally calls Go’s runtime.SetMutexProfileFraction(rate). 0 disables the mutex profile. Recommended values: 100 for production, 1 for debugging.

When a positive value is applied at startup, mo-service logs a line such as Block profiling enabled with rate: 5 or Mutex profiling enabled with fraction: 100.

Example

# Enable both profiles with debugging-level granularity while keeping the HTTP
# debug server available for pprof collection.
mo-service \
  --cfg etc/launch-with-dnservice/cn.toml \
  --debug-http 0.0.0.0:12345 \
  --block-profile-rate 1 \
  --mutex-profile-fraction 1

See also

  • --debug-http: listen address for the Go pprof HTTP handlers.

  • --profile-interval: duration for periodic profile rotation.