Interrupts-off Latency Tracer

modulename: trace_irqsoff.ko


Linux Kernel Configuration
└─>Kernel hacking
└─>Interrupts-off Latency Tracer
In linux kernel since version 2.6.27 (release Date: 2008-10-09)  
This option measures the time spent in irqs-off critical
sections, with microsecond accuracy.

The default measurement method is a maximum search, which is
disabled by default and can be runtime (re-)started

echo 0 > /sys/kernel/debug/tracing/tracing_max_latency

(Note that kernel size and overhead increase with this option
enabled. This option and the preempt-off timing option can be
used together or separately.)

source code: