Support for tracing block io actions

modulename: blktrace.ko

configname: CONFIG_BLK_DEV_IO_TRACE

Linux Kernel Configuration
└─>Tracers
└─>Support for tracing block io actions
In linux kernel since version 2.6.17 (release Date: 2006-06-17)  
Say Y here if you want to be able to trace the block layer actions
on a given queue. Tracing allows you to see any traffic happening
on a block device queue. For more information (and the userspace
support tools needed), fetch the blktrace tools from:

git://git.kernel.dk/blktrace.git

Tracing also is possible using the ftrace interface, e.g.:

echo 1 > /sys/block/sda/sda1/trace/enable
echo blk > /sys/kernel/debug/tracing/current_tracer
cat /sys/kernel/debug/tracing/trace_pipe

If unsure, say N.

source code: