CPU Frequency Logging Issue in Jetson Orin Nano 4G

Issue Overview

Users of the Jetson Orin Nano 4G with Jetson Linux 35.4.1 are experiencing an issue where the system continuously logs CPU frequency information in the dmesg output. This logging occurs endlessly, potentially filling up the system logs and making it difficult to identify other important messages. The issue appears to be present even when the system is functioning normally, particularly during resource-intensive tasks such as video capturing and processing.

The log entries follow a pattern similar to:

[timestamp] cpufreq: cpu0,cur:1387000,set:1510400,set ndiv:118

These entries show the current CPU frequency, the set frequency, and the set ndiv (presumably the clock divider) for different CPU cores.

Possible Causes

1. Software Bug: The primary cause of this issue is a known bug in CPU frequency sampling on older L4T (Linux for Tegra) releases.

2. Resource-Intensive Applications: While not the root cause, the presence of resource-intensive applications, such as video capturing and processing software, may exacerbate the logging issue by causing frequent CPU frequency changes.

3. Custom Board Configuration: The issue is reported on a custom board using the Jetson Orin Nano 4G module. It’s possible that specific configurations or modifications in the custom board design could contribute to the frequency of these log entries.

4. Outdated Software: The problem is associated with older versions of the Jetson software stack, indicating that running an outdated version is the primary reason for encountering this issue.

Troubleshooting Steps, Solutions & Fixes

1. Upgrade to JetPack 6:
   The most straightforward and recommended solution is to upgrade the system to JetPack 6. This update includes fixes for the CPU frequency sampling bug present in older L4T releases.

   Steps to upgrade:

   • Visit the NVIDIA Developer website to download JetPack 6.
   • Follow the official NVIDIA documentation for upgrading your Jetson device.
   • After upgrading, reboot the system and check if the excessive CPU frequency logging has stopped.

2. Monitor System Performance:
   While the logging itself may not indicate a performance issue, it’s worth monitoring the system to ensure that the frequent CPU frequency changes are not impacting performance.

   Use the following commands to monitor CPU usage and frequency:

   top
   cat /sys/devices/system/cpu/cpu*/cpufreq/scaling_cur_freq
   

3. Analyze Resource-Intensive Applications:
   If the issue persists or if you’re unable to upgrade immediately, consider optimizing the resource-intensive applications running on the device.

   • Profile the applications using tools like perf or vtune to identify any inefficiencies.
   • Consider implementing more efficient algorithms or utilizing hardware acceleration where possible.

4. Custom Board Considerations:
   For users with custom boards, ensure that:

   • The power management configurations are correctly set up.
   • Thermal management is adequate to prevent excessive thermal throttling.
   • The custom board design follows NVIDIA’s guidelines for Jetson module integration.

5. Temporary Log Filtering:
   As a temporary measure, you can filter out these specific log messages to prevent them from overwhelming your log files:

   dmesg | grep -v "cpufreq: cpu"
   

   To make this permanent, you can modify the kernel’s log level for the cpufreq subsystem, but this should be done cautiously and is not recommended as a long-term solution.

6. Consult NVIDIA Developer Support:
   If the issue persists after upgrading to JetPack 6, or if upgrading is not possible due to custom board constraints:

   • Reach out to NVIDIA Developer Support for further assistance.
   • Provide detailed information about your custom board configuration and any modifications made to the standard Jetson setup.

Remember that while these log messages may be annoying, they don’t necessarily indicate a functional problem with your system. However, addressing the root cause by upgrading to the latest software version is the best long-term solution for maintaining a healthy and efficient Jetson development environment.