我是 Linux 新手。我对线程优先级感到困惑。
top PR和ps PRI有什么区别，为什么不一样。</p>
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
1 root 20 0 2804 1664 1220 S 0.0 0.3 0:01.30 init
2 root 20 0 0 0 0 S 0.0 0.0 0:00.00 kthreadd
3 root RT 0 0 0 0 S 0.0 0.0 0:00.00 migration/0
4 root 20 0 0 0 0 S 0.0 0.0 0:00.00 ksoftirqd/0
5 root RT 0 0 0 0 S 0.0 0.0 0:00.00 watchdog/0
6 root 20 0 0 0 0 S 0.0 0.0 0:00.02 events/0
c@c-desktop:~$ ps -el
F S UID PID PPID C PRI NI ADDR SZ WCHAN TTY TIME CMD
4 S 0 1 0 0 80 0 - 701 poll_s ? 00:00:01 init
1 S 0 2 0 0 80 0 - 0 kthrea ? 00:00:00 kthreadd
1 S 0 3 2 0 -40 - - 0 migrat ? 00:00:00 migration/0
1 S 0 4 2 0 80 0 - 0 ksofti ? 00:00:00 ksoftirqd/0
5 S 0 5 2 0 -40 - - 0 watchd ? 00:00:00 watchdog/0
1 S 0 6 2 0 80 0 - 0 worker ? 00:00:00 events/0
我在源文件 procps/output.c 中找到了答案
In linux procps, the column labeled "PRI" in ps -l is -o opri
// # ps -C19,_20 -o pri,opri,intpri,priority,ni,pcpu,pid,comm
// PRI PRI PRI PRI NI %CPU PID COMMAND
// 0 99 99 39 19 10.6 8686 19
// 34 65 65 5 -20 94.7 8687 _20
// "priority" (was -20..20, now -100..39)
static int pr_priority(char *restrict const outbuf, const proc_t *restrict const pp){ /* -20..20 */
return snprintf(outbuf, COLWID, "%ld", pp->priority);
}
// "intpri" and "opri" (was 39..79, now -40..99)
static int pr_opri(char *restrict const outbuf, const proc_t *restrict const pp){ /* 39..79 */
return snprintf(outbuf, COLWID, "%ld", 60 + pp->priority);
}
// "pri_foo" -- match up w/ nice values of sleeping processes (-120..19)
// "pri_bar" -- makes RT pri show as negative (-99..40)
// "pri_baz" -- the kernel's ->prio value, as of Linux 2.6.8 (1..140)
// "pri" (was 20..60, now 0..139)
// "pri_api" -- match up w/ RT API (-40..99)
顶部的 PR 等于“优先级”
ps 中的 PRI 等于“opri”