Using blktrace

There are a few tools available to perform block devices I/O monitoring and profiling.

iotop, which we mentioned in the Exploring Yocto's tracing and profiling tools recipe, gives a general idea of the throughput on a system and a particular process. iostat provides many more statistics regarding CPU usage and device utilization, but does not provide per process details. Finally, blktrace, a GPLv2 licensed tool that monitors specific block devices' I/O at a low level, and can also compute I/O operations per second (IOPS).

This recipe will explain how to use blktrace to trace block devices and blkparse, to convert the traces into human readable format.

Flash filesystems, even if they are presented to the user space as block devices, cannot be profiled with blktrace.

Getting ready

To use blktrace and blkparse, you can add them to the target image by adding them specifically to your conf/local.conf file as in the following:

IMAGE_INSTALL_append = " blktrace" 

Alternatively, you can...