IONICE(1) IONICE(1) (NAME) ionice - / (SYNOPSIS) ionice [-c class] [-n level] [-t] -p PID ionice [-c class] [-n level] [-t] -P PGID ionice [-c class] [-n level] [-t] -u UID ionice [-c class] [-n level] [-t] command [argument] ... (DESCRIPTION) / (I/O) . -p ionice / . command ionice . class command "best-effort" . . : (Idle) / idle (grace period) / . / idle . . ( 2.6.25 ). (Best-effort) / . 0-7 . best-effort (round-robin) . 2.6.26 / "none" / best-effort . best-effort CPU nice : io_priority = (cpu_nice + 20) / 5. 2.6.26 / CFQ / CPU . / CPU nice ( 2.6.26). (Realtime) RT . RT (starvation) . best-effort . ( /non-root) . (OPTIONS) -c, --class class 0 none 1 realtime 2 best-effort 3 idle. -n, --classdata level . . realtime best-effort 0-7 ( ) 0 . -p, --pid PID... (PID) . -P, --pgid PGID... (PGID) . -t, --ignore . command ( ) . -u, --uid UID... (UID) . -h, --help . -V, --version . (NOTES) 2.6.13 / CFQ / . (EXAMPLES) o # ionice -c 3 -p 89 PID 89 / (idle) . o # ionice -c 2 -n 0 bash 'bash' best-effort . o # ionice -p 89 91 PID 89 91 . (AUTHORS) Jens Axboe , Karel Zak (SEE ALSO) ioprio_set(2) (REPORTING BUGS) . (AVAILABILITY) ionice util-linux . . util-linux 2.41.5 2026-03-31 IONICE(1)