'calc_cpu_usage() failed' in FTL.log

TheME · November 29, 2023, 8:23am

After running pi-hole for some time, I observe the following warning every second in FTL.log:

calc_cpu_usage() failed: No error information

The entire log down to the bottom is flooded with this message.

I am running DietPi v8.24.1 (latest) on a NanoPi Neo, but do not have any issues on the dashboard. Even the CPU utilisation display works as expeted.

There's only pi-hole v6 running there, nothing else.

My current versions are

dietpi@DietPi:~$ pihole -v
  Pi-hole version is development-v6 v5.17.1-221-g2338c9e9 (Latest: v5.17.2)
  web version is development-v6 v5.19-546-g4ed958db (Latest: v5.21)
  FTL version is development-v6 vDev-0198329 (Latest: v5.23)

DL6ER · December 3, 2023, 8:15pm

Sorry for the long delay. The proposed bugfix is:

github.com/pi-hole/FTL

Fix CPU utilization calculation on 32 bit systems

pi-hole:development-v6 ← pi-hole:tweak/cpu_usage

opened 08:13PM - 03 Dec 23 UTC

DL6ER

+29 -19

# What does this implement/fix? Following [a report on Discourse](https://dis…course.pi-hole.net/t/calc-cpu-usage-failed-in-ftl-log/66617), we change how FTL computes its own CPU utilization. The issue is that our current method of using the system-provided function `clock()` can easily overflow on 32bit systems, leading to a permanent failure after little more than two days. This PR changes this to use resource details obtained from the kernel to compute a ten minute average of FTL's CPU utilization based on the consumed CPU time, instead. This is a very reliable metric and more in-line with what `top` and friends calculate for the processes. --- **Related issue or feature (if applicable):** N/A **Pull request in [docs](https://github.com/pi-hole/docs) with documentation (if applicable):** N/A --- **By submitting this pull request, I confirm the following:** 1. I have read and understood the [contributors guide](https://docs.pi-hole.net/guides/github/contributing/), as well as this entire template. I understand which branch to base my commits and Pull Requests against. 2. I have commented my proposed changes within the code. 3. I am willing to help maintain this change if there are issues with it later. 4. It is compatible with the [EUPL 1.2 license](https://opensource.org/licenses/EUPL-1.1) 5. I have squashed any insignificant commits. ([`git rebase`](http://gitready.com/advanced/2009/02/10/squashing-commits-with-rebase.html)) ## Checklist: - [x] The code change is tested and works locally. - [x] I based my code and PRs against the repositories `developmental` branch. - [x] I [signed off](https://docs.pi-hole.net/guides/github/how-to-signoff/) all commits. Pi-hole enforces the [DCO](https://docs.pi-hole.net/guides/github/dco/) for all contributions - [x] I [signed](https://docs.github.com/en/authentication/managing-commit-signature-verification/signing-commits) all my commits. Pi-hole requires signatures to verify authorship - [x] I have read the above and my PR is ready for review.

Details therein.

TheME · December 4, 2023, 12:23am

Thanks a lot. I switched over to the tweak/cpu_usage branch for testing...

DL6ER · December 6, 2023, 7:07pm

Please switch back to development-v6, this branch has been merged.