Best way to measure performance and efficiency

Hello,
Because im parsing big amount of logs, i want to reduce the time it takes to parse them with logstash.

Most of the configuration im using grok, so i want to compare it in different ways on different log files sizes.

What is the best way to measure the lines per second logstash is parsing?

I tried:
metrics {
meter => "events"
add_tag => "metric"
}

but i cant figure what the output is telling me?( it also changes it values every second).
output:
"events" => {
"rate_1m" => 0.4848158243742716,
"rate_15m" => 47.6986304224836,
"count" => 331, ----(This is number of lines in the log file)
"rate_5m" => 24.762913972657874

Thanks for the help.

You are looking at the per-second event rates over sliding windows of 1, 5, and 15 minutes.

The latest version of Logstash exposes a monitoring API which can give you better insight into how different parts of the pipeline performs.