Reserved for the bravest of tinkerers, this section provides direct access to low level system controls that affect storage behaviour, power suspension, and process scheduling.
These settings are powerful but risky!
Altering them without a clear understanding can impact stability, performance, or data integrity. Adjust only if you know what you are doing or if you like a bit of excitement in your life.
Controls how aggressively the system moves inactive memory pages to swap storage. Lower values keep data in RAM longer, improving performance at the cost of higher memory use.
Write Back Threshold
Defines the percentage of system memory that can contain unwritten (dirty) data before the kernel forces it to be written to disk. Higher values delay writes but risk larger bursts of I/O.
Background Write Back
Sets the memory percentage that triggers background write-back activity. Lower values reduce latency by keeping storage more up-to-date but may increase write frequency.
Cache Reclamation
Determines how aggressively the kernel reclaims cached file data. Higher values free cache space quickly, while lower values improve access times for frequently used files.
I/O Merge Policy
Configures how the kernel merges adjacent I/O requests into single operations. Disabling merges may improve responsiveness on flash storage with low latency.
Queue Depth
Sets the maximum number of pending I/O operations allowed per device. Higher values increase throughput for heavy workloads but also raise memory usage.
Read Ahead Size
Specifies how much data the kernel preloads before an application requests it. Larger read-ahead values benefit sequential reads, while smaller ones suit random access patterns.
Swap Read-Ahead
Defines how many memory pages are prefetched from swap during reads. Lower values reduce latency; higher values improve performance for sustained swap activity.
Realtime Timeslice
Determines how long real time tasks can run before being rescheduled. Lower values enhance responsiveness, while higher values favour long, continuous processing.
I/O Stats
Enables or disables kernel level tracking of per-device I/O statistics. Disabling this feature can slightly improve performance by reducing overhead.
Idle Flush Mode
When enabled, the system flushes dirty data during idle periods instead of waiting for write thresholds. Useful for flash storage and reducing power draw while inactive.
Fork Optimisation
Prioritises newly created (forked) processes to run before their parent. Can improve perceived load times in some applications.
Scheduler Scaling
Adjusts kernel scheduler behaviour dynamically based on CPU core count. Disabling this keeps tuning consistent across multi-core and single-core systems.
Disk Tuning
Switches between predefined disk or card performance profiles. Useful for optimising behaviour on specific SD cards or external storage.
Suspend Power State
Changes how the system enters and resumes from sleep mode. Different suspend states balance between faster wake-up and lower idle power consumption.
