How to check Logstash speed?

WOW!! it helps Navneet, but I have a quick question . Since my prod LS thread is already running , so do I need to create another thread for metrics LS filter.

What I observe even if I stopped all LS , it still giving me the output.So my concern is if nothing is running then what is this output.

rate: 19618.364898825177
rate: 19630.425007634054
rate: 19627.912402753394
rate: 19632.04511484765
rate: 19659.802086904296
rate: 19677.951837923785
rate: 19690.09294661005
rate: 19685.11227759938
rate: 19692.81101880793
rate: 19706.99425863745
rate: 19687.549519329303