nice¶

Intro¶

nice - Change the nice value of the current process, influence scheduling priority

Description¶

The nice() system call can be used to change the nice value of the current process, which influences its scheduling priority. A lower nice value causes more favorable scheduling, and a process with a "high" nice value will be scheduled less often than other processes. A process must be privileged to raise its nice value (i.e., to decrease its priority).

There are some edge-cases with nice(): if a privileged process calls nice() with a non-zero value, then it might cause the scheduling priority to drop too far or become too favorable; this could put system instability. Additionally, even a process with the correct privileges cannot raise its nice value above its current value.

Arguments¶

inc:int - The 'inc' argument specifies an increment to be added to the nice value of the current process. A positive value adds to the nice value and a negative value subtracts from it. For the superuser, the range of valid nice values is from -20 (most favorable) to +19 (least favorable). For a normal process, the range is from 0 to PRIO_MAX (usually 20).

Hooks¶

sys_nice¶

Type¶

kprobe

Purpose¶

To monitor and log when the nice syscall is used.

Example Use Case¶

Nice() can be used to measure the relative performance of two applications running against each other on a system. By setting one application to a slightly higher nice value, you can prioritize the other application, thus obtaining an accurate performance measurement.

Issues¶

No known issues.

The sched_setscheduler function can be used to change the scheduling policy and priority of a process. This event is typically a better option than the nice() system call if you want to tailor the scheduling priority of a process.

This document was automatically generated by OpenAI and needs review. It might not be accurate and might contain errors. The authors of Tracee recommend that the user reads the "events.go" source file to understand the events and their arguments better.