Tag: Stability Testing

Overclocking and Stability Testing the Raspberry Pi 2 – Part 4: SD Storage Testing

Stability Testing an Overclocked Raspberry Pi
 

In the final part of the series of posts concerning Overclocking and Stability Testing the Raspberry Pi, we will be checking SD Card Storage reliability with the elinux.org Stability Test Script.

Smashed Hard Drive – Image: thefileroom.com
Smashed Hard Drive – Image: thefileroom.com

Introducing the Overclocking Stability Test Script

The Stability Test Script is a program from elinux.org, described on that site as:

…a script to stress-test the stability of the system, specifically the SD card. If this script runs to completion, without any errors showing in dmesg, then the Raspberry Pi is probably stable with these settings

Why Stability Test the Pi’s SD Storage?

As noted in Part One of this series, in the early days (and years) of the Pi’s existence there were apparently widespread issues whereby overclocked machines experienced corrupted SD card data. The official, definitive, information on this issue comes from elinux.org: SD Card Usage with Overclocking

Stability of SD card operations when using overclocking is independent of:

  • Filesystem type, ext4, NTFS or other.
  • SD card vendor.
  • The Raspberry Pi model.
  • SD card size – verified for 16 GB and up.

What does matter is when you under-power your Raspberry Pi (that is, less than the Raspberry Pi base setup specifications!).

There initially was an increased likelihood of SD card corruption when using overclocking. This is no longer an issue (with firmware from Nov 11 2013 or later).

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Overclocking and Stability Testing the Raspberry Pi 2 – Part 2: Stability Testing

Stability Testing an Overclocked Raspberry Pi
 

Checking that the system is reliable after applying overclocking

Overclocking is nothing without Stability. Image - www.wallpaper.ge/
Overclocking is nothing without Stability. Image – http://www.wallpaper.ge/

Following on from Part 1 of this post on Overclocking, we turn our attention to stability testing the system; this process is crucial, as simply witnessing the Pi boot to the command shell, or a Graphical User Interface (GUI) isn’t proof that a given combination of overclock settings is stable.

Sometimes an instability will only become apparent after several hours of intensive activity on the system (which is highly likely if using the system for gaming with an installation such as RetroPie).

There are three tools / scripts which I have used in the stability testing processes. For each I will provide instructions on obtaining and installing (or running, as appropriate):

  • MPrime.py
    – Python script to search for prime numbers, which heavily loads the CPU
    – User selectable numeric range to test
    – User selectable number of cores to run upon simultaneously.
  • Memtester
    – Tests the stability of the RAM
    – Natively runs on a single CPU core, but can be run on all cores using multiple remote SSH sessions, or the Screen tool
  • Stability Test Script
    – Reads the entire SD card 10x. Tests RAM and I/O
    – Writes 512 MB test file, 10x.
    – Script can be easily updated to change the number of reads/writes etc.

This post covers the use of mprime. Subsequent posts covers the use of Memtester and the Stability Test Script. Please use the links in the above list to access the relevant information.

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Overclocking and Stability Testing the Raspberry Pi 2 – Part 1: Overclocking in Depth

More speed for free?

Silhouette Clockwork - Image Original: andreakihlstedt.com
Silhouette Clockwork – Original Image: andreakihlstedt.com

Overclocking and Stability Testing – Part 1

When using the Raspberry Pi 2 to run any sort of intensive software, which certainly includes emulating classic video games systems using RetroPie, you really need all the processing and graphical horsepower you can get. Luckily there’s more available under the bonnet of the Pi with a little tweaking.

Note: For additional considerations when overclocking the Raspberry Pi 3, please see Overclocking the Raspberry Pi 3: Thermal Limits and Optimising for Single vs Multicore Performance, in addition to the current post.

Topics Covered In Part 1

Topics Covered In Parts 2, 3, and 4

Disclaimer

Overclocking the Pi is supported by tools provided with standard operating system distributions, such as Raspbian, and sanctioned by the manufacturer (with some caveats, as discusssed below). That said, the following details only my own research and experiences with a single Raspberry Pi 2 device; as always, your mileage may vary.

Assistance for those new to Linux

Making changes to the Overclock settings on the Pi, and testing the changes for stability, requires a little knowledge of the Linux command shell.

Please see my related posts for a basic guide which should help those new to Linux and/or Raspbian get started:

Overclocking and Power – Use a Quality PSU

When overclocking it is worth ensuring that your Pi is serviced by a good quality Power Supply Unit (PSU), as this is often a point of failure. Not all micro usb supplies, or cables, are up to the task.

Please see my earlier post covering this topic here.

Why Overclock?

The Raspberry Pi 2, as with the predecessor Pi, can be setup to run faster than the default system, effectively giving extra processing and graphical capabilities for free. For retro gaming this can be critical, and is especially true of the N64 emulators, as well as when running more demanding PlayStation releases such as Gran Turismo 2.

Raspberry Pi System Architecture

The Raspberry Pi 2 contains a System on a Chip (SoC), which integrates a quad-core ARM CPU and a Broadcom VideoCore IV Graphics processing unit (GPU), alongside 1GB of SDRAM memory.

Raspberry Pi 2 Model 2
Raspberry Pi 2

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