RPi Clock Frequency Test

Clock frequency is the number of times the CPU “ticks” per second. As the CPU is a synchronized circuit, the performance depends directly on it.

None of the Raspberry Pi models have a built-in real-time clock. When booting, the time is set either manually, or configured from a previously saved state at shutdown to provide relative consistency for the file system. The Network Time Protocol is used to update the system time when connected to a network. You should run the device at a decent clock speed to ensure that the responsiveness of the system is good, and then put the system in sleep mode when there is no processing to do. Sometimes you might have to do some benchmarking to decide if you should run the system faster and then enter sleep, or run it slower to keep the active current down. This is why, it is important for administrators to periodically check the clock frequency of the device. This can be easily done using the RPi Clock Frequency test.

This test reports the current clock frequency of the Raspberry Pi and alerts administrators, if abnormalities are detected.

Target of the test : A Raspberry Pi Device

Agent deploying the test : An external agent

Outputs of the test : One set of results for the Raspberry Pi device is being monitored.

Configurable parameters for the test
Parameter Description

Test period

How often should the test be executed

Host

The IP address of the that is being monitored.

Use Sudo

The eG agent runs native Linux commands to pull metrics from the Raspberry Pi system. By default, the eG agent does not require any special permissions to execute these commands. In some highly-secure Linux environments however, the eG agent install user may not have the permissions to execute these commands directly. To grant permission to eG agent install user for command execution, first, perform the following steps:

  • Edit the SUDOERS file on the target host and append an entry of the following format to it:

    <eG_agent_install_user> ALL=(ALL) NOPASSWD

  • For instance, if the eG agent install user is eguser, then the entry in the SUDOERS file should be:

    eguser ALL=(ALL) NOPASSWD

  • Finally, save the file.

Then, when configuring this test using the eG admin interface, set the USE SUDO parameter to Yes. This will enable the eG agent to execute the Linux commands and retrieve the metrics.

Sudo Path

This parameter is relevant only when the USE SUDO parameter is set to ‘Yes’. By default, the SUDO PATH is set to none. This implies that the sudo command is in its default location – i.e., in the /usr/bin or /usr/sbin folder of the target host. In this case, once the Use Sudo flag is set to Yes, the eG agent automatically runs the sudo command from its default location. However, if the sudo command is available in a different location in your environment, you will have to explicitly specify the full path to the sudo command in the Sudo Path text box.

Measurements made by the test
Measurement Description Measurement Unit Interpretation

Frequency

Indicates the current clock frequency of this device.

MHz

By reading the clock frequency, you can figure out if overclocking is required or not. Overclocking is the process of forcing a GPU core/memory to run faster than its manufactured frequency.

Overclocking can have both positive and negative effects on GPU performance. For instance, memory overclocking helps on cards with low memory bandwidth, and with games with a lot of post-processing/textures/filters like AA that are VRAM intensive. On the other hand, you should be aware of few risks that occurs due to overclocking. They are:

  1. Life reduction - components may fail sooner
  2. Heat generation - operating at higher speeds generate more heat (heat sinks are recommended)
  3. File corruption - many have observed file corruptions at unoptimized overclocking settings Warranty-Voiding - forced overvolting will void your warranty

In the context of Overclocking, overvolting refers to raising the ON-CHIP generated voltage driving the System-on Chip Processor. Pi 1 and Pi 2 have a default clock speed of 250 MHz, whereas the Pi 3 and Pi Zero have a default clock speed of 400 MHz.

Forcing the Pi to run above 400MHz or turbo mode removes its ability to throttle its clock if it detects that the processor is overheating. This will damage your Pi and can also affect your warranty on the Pi.

An appropriately sized heat sink is needed to protect the chip from serious overheating and monitoring your results with the right tools and doing the necessary research are all critical steps on the path to safe and successful overclocking.