3.2.3. LTP-DDT Validation

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LTP-DDT Overview

LTP-DDT is a test application used by Texas Instruments to validate Linux releases.

It is based on LTP.
LTP validates many kernel areas, such as memory management, scheduler and system calls. LTP-DDT extends LTP’s core Kernel tests with tests to validate Kernel drivers developed by Texas Instruments. LTP-DDT focuses on embedded device driver tests. It contains hundreds of tests that validate functionality and performance of device drivers. LTP-DDT also contains tests to validate System’s use cases and overall System’s stability.

LTP-DDT uses LTP’s test infrastructure, such as:

  • Test execution drivers (PAN)

  • Top-level test scripts (i.e. runltp)

  • Same Folder Hierarchy and test case definition format

LTP-DDT test cases are LTP test cases and vice-versa.

The main additions or ‘enhacements’ of LTP-DDT compared to LTP are:

  • PLATFORM files. LTP-DDT uses PLATFORM files to identify platform hardware and software features.

  • OVERRIDE mechanism. Default test case parameters are automatically overridden based on PLATFORM features.

  • ATOMIC scripts. Code reuse is foster by writing scripts that implement small well-defined actions. Test scripts rely on these atomic scripts to execute their actions.

  • AUTOMATIC FILTERING. Test cases are filtered based on the test requirements and the PLATFORM features.

  • TESTCASE ANNOTATIONS. Test scenario files are annotated with following annotations @name, @desc, @requires and @setup_requires. The @requires and @setup_requires are used to select test cases at run time based on the PLATFORM features.

  • All LTP-DDT test cases and test code reside in <testcases-root>/ddt/ and <testcode-root>/ddt/ folders respectively.

LTP-DDT Highlights

  • Easy to use (automatically filter test cases not applicable for platform)

  • Easy to support new platforms (just define the platform file)

  • Test cases can be easily wrap or imported to Test Management Systems (Use of testcase annotations facilitates this)

  • High Code Reuse (atomic scripts and test scripts are reused and parameters are adjusted on the fly)

Test Suites

LTP-DDT contains tests cases that uses other open source tools such as iperf, evtest, rt-tests (cyclictest), lmbench and others.
Test suites currently available include among others:
  • alsa

  • cpu hotplug

  • crypto

  • timers

  • emmc

  • mmc/sd

  • ethernet

  • fbdev

  • gpio

  • gstreamer (multimedia)

  • hdmi

  • i2c

  • ipc

  • latency under different use cases (important for RT kernel)

  • lmbench

  • memory tests

  • mm (ltp’s memory management)

  • msata

  • nand

  • nor

  • pci

  • pipes (ltp)

  • power management

  • programmable real-time unit (PRU)

  • pwm

  • qspi

  • realtime (ltp)

  • rng

  • rtc

  • sata

  • scheduler (ltp)

  • sgx (graphics)

  • smp

  • spi

  • syscalls (ltp)

  • system (use-cases, e.g. multiple tests running in parallel)

  • thermal

  • timers (ltp)

  • touchscreen

  • uart

  • usb host (multiple tests with different classes)

  • usb device

  • v4l2

  • vlan

  • dwt

  • wlan

Device Under Tests Supported

Supported platforms with LTP-DDT - can be found here

Host Platform Requirements

Linux host is required :

  • for compiling LTP-DDT.

  • to host the NFS server to boot the EVM with NFS as root filesystem

  • to run host utilities - e.g.iperf

Host Software Requirements

  • GCC Tool chain for ARM

  • Serial console terminal application

  • TFTP and NFS servers. NFS server is required only in case of NFS boot.

  • iperf utility on the host.

Filesystem Requirements

LTP-DDT relies on other open source test tools. The following test tools must be available in the target filesystem to run ltp-ddt:

  • alsa utilities

  • evtest

  • hdparm

  • iperf

  • lmbench

  • rt-tests (cyclictest)

There is an Arago/OE recipe here that builds a filesystem image w/ the above tools plus:

  • bonnie++

  • iozone3

  • ltp-ddt


Clone the project

git clone https://git.ti.com/git/test-automation/ltp-ddt.git
Installation instructions are in the README-DDT file. Check sections 6) and 7)
There is also an Arago/OE recipe to build ltp-ddt here

Running Tests

  • Run DDT tests the same way you run LTP tests. Use ltprun program and pass to

it the test scenario file in the runtest directory (option -f) to run and the platform (option -P) to use. For example:

./runltp -P am180x-evm -f ddt/lmbench
The platform name specified with -P option must exist in the platforms/ dir.
It is also possible to run tests without -P option, in such case the ltprun script won’t filter test cases and it is possible that tests cases not supported by the platform you are running on will be called.
  • In addition to selecting test scenarios using -f option, users can also

filter test cases using -s PATTERN option. These option select test cases based on the test case TAG specified in the test scenario file.
  • The runltp script have lot of options. Some useful ones for stress tests are:

-t DURATION: Define duration of the test in s,m,h,d.
-x INSTANCES: Run multiple test instances in parallel.
-c <options>: Run test under additional background CPU load
-D <options>: Run test under additional background load on Secondary storage
-m <options>: Run test under additional background load on Main memory
-i <options>: Run test under additional background load on IO Bus
-n          : Run test with network traffic in background.

Please refer to README-DDT file section 8) for more details.

  • Running NAND Sanity Tests

– Run all NAND sanity tests

Using below command to run NAND sanity tests.

./runltp -P <platform> -s "NAND_S_" -S skiplist

If there are more than one flash filesystem supported, say, jffs2 and ubifs and you don’t run jffs2 test cases. You need create a file called ‘skiplist’ (this filename could be anything) and put to-be-skipped test case tag in this file. Here is the content of skiplist to skip jffs2 test cases.

@ cat skiplist

– Run NAND performance test

./runltp -P <platform> -s "NAND_L_PERF" -S skiplist


LTP-DDT is an open source project.
The LTP-DDT sources are hosted here https://git.ti.com/git/test-automation/ltp-ddt.git
Developers are encouraged to join the Arago mailing list at meta-arago@lists.yoctoproject.org
Of course patches and comments are welcome, please send them to meta-arago@lists.yoctoproject.org mailing list.
Developers are encouraged to read sections 3) and 4) in the README-DDT file before submitting patches.