glances shows my 5800X3D with iowait @ ~20% (min / max = 7 / 37%). The LLM tells me: The Kyber scheduler is the cause. It is designed to prevent disk congestion by limiting how many requests are sent to the drive. Because your Btrfs setup is configured to commit data every 90 seconds, it creates a massive burst of data. Kyber detects this burst, hits its internal latency limit, and forces the CPU to pause. This pause is the iowait you are seeing. The following command disables kernel-level...