xref: /external/ltp/testcases/kernel/controllers/io-throttle

TEST SUITE:

The directory io-throttle contains the tests related to block device I/O
bandwdith controller.

More testcases are expected to be added in future.

TESTS AIM:

The aim of the tests is to check the block device I/O throttling functionality
for cgroups.

FILES DESCRIPTION:

iobw.c
---------------
Simple benchmark to generate parallel streams of direct I/O (O_DIRECT). This
benchmark fork()s one task per stream. Each task creates a separate file in the
current working directory, fills it with data using O_DIRECT writes and re-read
the whole file always in O_DIRECT mode. Different timestamps are used to
evaluate per-task I/O rate and total I/O rate (seen by the parent).

myfunctions.sh
----------
This file contains the functions which are common for the io-throttle tests.
For ex.  the setup and cleanup functions which do the setup for running the
test and do the cleanup once the test finishes. The setup() function creates
/dev/blockioctl directory and mounts cgroup filesystem on it with memory
controller. It then creates a number(n) of groups in /dev/blockioctl. The
cleanup function does a complete cleanup of the system.

Most of the error scenarios have been taken care of for a sane cleanup of the
system. However if cleanup fails in any case, just manually execute the
commands written in cleanup function in myfunctions.sh.
One of the most common causes of failed cleanup is that you have done cd into
any of the groups in controller dir tree.

run_io_throttle_test.sh
------------------
This script creates different scenarios for I/O bandwidth controller testing
and fires (n) tasks in different groups to write and read different I/O streams
etc. It waits for the return status from tasks and reports test pass/fail
accordingly.

Makefile
--------
The usual makefile for this directory

PASS/FAIL CRITERION:
==================
The test cases are intelligent enough in deciding the pass or failure of a
test.

README:
--------
This file.