Parse the output from the excellent iotop (https://github.com/Tomas-M/iotop) tool and produce graphs showing the per-process I/O
- Install iotop either from your distribution's package manager or from building from source
- Launch iotop with the below arguments
# iotop -o --batch -t -k -P -q > /tmp/ioresults.txt
This will record the I/O usage of active processes once a second and print the results to /tmp/ioresults.txt (obviously use whatever path you wish)
- Parse the results with the parser script from this repo
$ python ./iotop_parser.py /tmp/ioresults.txr
The script will produce graphs in the ./output directory. Each process seen performing I/O during the iotop run will have its own graph
The resulting graphs will have two Y axis:
- The left axis shows how much data the process is reading/writing in KB/s
- The right axis shows the amount of time (%) the process is delayed waiting for IO to complete or waiting for page fault I/O (swapping data in)
iotop reads this data over netlink using the taskstats interface, see https://www.kernel.org/doc/Documentation/accounting/taskstats.txt and https://docs.kernel.org/accounting/taskstats-struct.html for more details