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