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34 static char sccsid[] = "@(#)proc_compare.c 8.2 (Berkeley) 9/23/93";
38 #include <sys/cdefs.h>
39 __FBSDID("$FreeBSD$");
41 #include <sys/param.h>
49 * Returns 1 if p2 is "better" than p1
51 * The algorithm for picking the "interesting" process is thus:
53 * 1) Only foreground processes are eligible - implied.
54 * 2) Runnable processes are favored over anything else. The runner
55 * with the highest cpu utilization is picked (p_estcpu). Ties are
56 * broken by picking the highest pid.
57 * 3) The sleeper with the shortest sleep time is next. With ties,
58 * we pick out just "short-term" sleepers (TDF_SINTR == 0).
59 * 4) Further ties are broken by picking the highest pid.
61 * If you change this, be sure to consider making the change in the kernel
62 * too (^T in kern/tty.c).
64 * TODO - consider whether pctcpu should be used.
67 #define ISRUN(p) (((p)->ki_stat == SRUN) || ((p)->ki_stat == SIDL))
68 #define TESTAB(a, b) ((a)<<1 | (b))
74 proc_compare(struct kinfo_proc *p1, struct kinfo_proc *p2)
80 * see if at least one of them is runnable
82 switch (TESTAB(ISRUN(p1), ISRUN(p2))) {
89 * tie - favor one with highest recent cpu utilization
91 if (p2->ki_estcpu > p1->ki_estcpu)
93 if (p1->ki_estcpu > p2->ki_estcpu)
95 return (p2->ki_pid > p1->ki_pid); /* tie - return highest pid */
100 switch (TESTAB(p1->ki_stat == SZOMB, p2->ki_stat == SZOMB)) {
106 return (p2->ki_pid > p1->ki_pid); /* tie - return highest pid */
109 * pick the one with the smallest sleep time
111 if (p2->ki_slptime > p1->ki_slptime)
113 if (p1->ki_slptime > p2->ki_slptime)
116 * favor one sleeping in a non-interruptible sleep
118 if (p1->ki_tdflags & TDF_SINTR && (p2->ki_tdflags & TDF_SINTR) == 0)
120 if (p2->ki_tdflags & TDF_SINTR && (p1->ki_tdflags & TDF_SINTR) == 0)
122 return (p2->ki_pid > p1->ki_pid); /* tie - return highest pid */