11590Srgrimes/*- 21590Srgrimes * Copyright (c) 1990, 1993 31590Srgrimes * The Regents of the University of California. All rights reserved. 41590Srgrimes * 51590Srgrimes * Redistribution and use in source and binary forms, with or without 61590Srgrimes * modification, are permitted provided that the following conditions 71590Srgrimes * are met: 81590Srgrimes * 1. Redistributions of source code must retain the above copyright 91590Srgrimes * notice, this list of conditions and the following disclaimer. 101590Srgrimes * 2. Redistributions in binary form must reproduce the above copyright 111590Srgrimes * notice, this list of conditions and the following disclaimer in the 121590Srgrimes * documentation and/or other materials provided with the distribution. 131590Srgrimes * 4. Neither the name of the University nor the names of its contributors 141590Srgrimes * may be used to endorse or promote products derived from this software 151590Srgrimes * without specific prior written permission. 161590Srgrimes * 171590Srgrimes * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 181590Srgrimes * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 191590Srgrimes * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 201590Srgrimes * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 211590Srgrimes * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 221590Srgrimes * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 231590Srgrimes * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 241590Srgrimes * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 251590Srgrimes * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 261590Srgrimes * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 271590Srgrimes * SUCH DAMAGE. 281590Srgrimes */ 291590Srgrimes 30128231Sbde#if 0 31128231Sbde#ifndef lint 32128231Sbdestatic char sccsid[] = "@(#)proc_compare.c 8.2 (Berkeley) 9/23/93"; 33128231Sbde#endif /* not lint */ 34128231Sbde#endif 35128231Sbde 3687674Smarkm#include <sys/cdefs.h> 3787674Smarkm__FBSDID("$FreeBSD$"); 3887674Smarkm 391590Srgrimes#include <sys/param.h> 40128231Sbde#include <sys/proc.h> 411590Srgrimes#include <sys/time.h> 4269896Smckusick#include <sys/user.h> 431590Srgrimes 441590Srgrimes#include "extern.h" 451590Srgrimes 461590Srgrimes/* 471590Srgrimes * Returns 1 if p2 is "better" than p1 481590Srgrimes * 491590Srgrimes * The algorithm for picking the "interesting" process is thus: 501590Srgrimes * 511590Srgrimes * 1) Only foreground processes are eligible - implied. 521590Srgrimes * 2) Runnable processes are favored over anything else. The runner 531590Srgrimes * with the highest cpu utilization is picked (p_estcpu). Ties are 541590Srgrimes * broken by picking the highest pid. 551590Srgrimes * 3) The sleeper with the shortest sleep time is next. With ties, 56128231Sbde * we pick out just "short-term" sleepers (TDF_SINTR == 0). 571590Srgrimes * 4) Further ties are broken by picking the highest pid. 581590Srgrimes * 591590Srgrimes * If you change this, be sure to consider making the change in the kernel 601590Srgrimes * too (^T in kern/tty.c). 611590Srgrimes * 621590Srgrimes * TODO - consider whether pctcpu should be used. 631590Srgrimes */ 641590Srgrimes 65243183Sed#define ISRUN(p) (((p)->ki_stat == SRUN) || ((p)->ki_stat == SIDL)) 66243183Sed#define TESTAB(a, b) ((a)<<1 | (b)) 67243183Sed#define ONLYA 2 68243183Sed#define ONLYB 1 69243183Sed#define BOTH 3 701590Srgrimes 711590Srgrimesint 7297981Sjmallettproc_compare(struct kinfo_proc *p1, struct kinfo_proc *p2) 731590Srgrimes{ 741590Srgrimes 751590Srgrimes if (p1 == NULL) 761590Srgrimes return (1); 771590Srgrimes /* 781590Srgrimes * see if at least one of them is runnable 791590Srgrimes */ 801590Srgrimes switch (TESTAB(ISRUN(p1), ISRUN(p2))) { 811590Srgrimes case ONLYA: 821590Srgrimes return (0); 831590Srgrimes case ONLYB: 841590Srgrimes return (1); 851590Srgrimes case BOTH: 861590Srgrimes /* 871590Srgrimes * tie - favor one with highest recent cpu utilization 881590Srgrimes */ 8969896Smckusick if (p2->ki_estcpu > p1->ki_estcpu) 901590Srgrimes return (1); 9169896Smckusick if (p1->ki_estcpu > p2->ki_estcpu) 921590Srgrimes return (0); 93128231Sbde return (p2->ki_pid > p1->ki_pid); /* tie - return highest pid */ 941590Srgrimes } 951590Srgrimes /* 96243183Sed * weed out zombies 971590Srgrimes */ 9869896Smckusick switch (TESTAB(p1->ki_stat == SZOMB, p2->ki_stat == SZOMB)) { 991590Srgrimes case ONLYA: 1001590Srgrimes return (1); 1011590Srgrimes case ONLYB: 1021590Srgrimes return (0); 1031590Srgrimes case BOTH: 10469896Smckusick return (p2->ki_pid > p1->ki_pid); /* tie - return highest pid */ 1051590Srgrimes } 1061590Srgrimes /* 1071590Srgrimes * pick the one with the smallest sleep time 1081590Srgrimes */ 10969896Smckusick if (p2->ki_slptime > p1->ki_slptime) 1101590Srgrimes return (0); 11169896Smckusick if (p1->ki_slptime > p2->ki_slptime) 1121590Srgrimes return (1); 1131590Srgrimes /* 1141590Srgrimes * favor one sleeping in a non-interruptible sleep 1151590Srgrimes */ 11683366Sjulian if (p1->ki_tdflags & TDF_SINTR && (p2->ki_tdflags & TDF_SINTR) == 0) 1171590Srgrimes return (1); 11883366Sjulian if (p2->ki_tdflags & TDF_SINTR && (p1->ki_tdflags & TDF_SINTR) == 0) 1191590Srgrimes return (0); 12087674Smarkm return (p2->ki_pid > p1->ki_pid); /* tie - return highest pid */ 1211590Srgrimes} 122