Histogram triggers

modulename: trace_events_hist.ko


Linux Kernel Configuration
└─>Kernel hacking
└─>Histogram triggers
In linux kernel since version 3.10 (release Date: 2013-06-30)  
Hist triggers allow one or more arbitrary trace event fields
to be aggregated into hash tables and dumped to stdout by
reading a debugfs/tracefs file. They're useful for
gathering quick and dirty (though precise) summaries of
event activity as an initial guide for further investigation
using more advanced tools.

Inter-event tracing of quantities such as latencies is also
supported using hist triggers under this option.

source code: