Performance

These statistics can be enabled by setting enable_dispatcher_stats to true.

Warning

Note that enabling dispatcher stats records a value for each iteration of the event loop on every thread. This should normally be minimal overhead, but when using , it will send each observed value over the wire individually because the statsd protocol doesn’t have any way to represent a histogram summary. Be aware that this can be a very large volume of data.

The event dispatcher for the main thread has a statistics tree rooted at server.dispatcher., and the event dispatcher for each worker thread has a statistics tree rooted at listener_manager.worker_.dispatcher., each with the following statistics:

Note that any auxiliary threads are not included here.

Watchdog

In addition to event loop statistics, Envoy also include a configurable system that can increment statistics when Envoy is not responsive and optionally kill the server. The statistics are useful for understanding at a high level whether Envoy’s event loop is not responsive either because it is doing too much work, blocking, or not being scheduled by the OS.