proc_compare.c revision 97981
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 * 3. All advertising materials mentioning features or use of this software 141590Srgrimes * must display the following acknowledgement: 151590Srgrimes * This product includes software developed by the University of 161590Srgrimes * California, Berkeley and its contributors. 171590Srgrimes * 4. Neither the name of the University nor the names of its contributors 181590Srgrimes * may be used to endorse or promote products derived from this software 191590Srgrimes * without specific prior written permission. 201590Srgrimes * 211590Srgrimes * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 221590Srgrimes * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 231590Srgrimes * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 241590Srgrimes * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 251590Srgrimes * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 261590Srgrimes * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 271590Srgrimes * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 281590Srgrimes * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 291590Srgrimes * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 301590Srgrimes * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 311590Srgrimes * SUCH DAMAGE. 321590Srgrimes */ 331590Srgrimes 3487674Smarkm#include <sys/cdefs.h> 3587674Smarkm 3687674Smarkm__FBSDID("$FreeBSD: head/usr.bin/w/proc_compare.c 97981 2002-06-07 01:41:54Z jmallett $"); 3787674Smarkm 381590Srgrimes#ifndef lint 3987674Smarkmstatic const char sccsid[] = "@(#)proc_compare.c 8.2 (Berkeley) 9/23/93"; 4069896Smckusick#endif 411590Srgrimes 421590Srgrimes#include <sys/param.h> 431590Srgrimes#include <sys/time.h> 4469896Smckusick#include <sys/user.h> 451590Srgrimes 461590Srgrimes#include "extern.h" 471590Srgrimes 481590Srgrimes/* 491590Srgrimes * Returns 1 if p2 is "better" than p1 501590Srgrimes * 511590Srgrimes * The algorithm for picking the "interesting" process is thus: 521590Srgrimes * 531590Srgrimes * 1) Only foreground processes are eligible - implied. 541590Srgrimes * 2) Runnable processes are favored over anything else. The runner 551590Srgrimes * with the highest cpu utilization is picked (p_estcpu). Ties are 561590Srgrimes * broken by picking the highest pid. 571590Srgrimes * 3) The sleeper with the shortest sleep time is next. With ties, 5871592Sjhb * we pick out just "short-term" sleepers (PS_SINTR == 0). 591590Srgrimes * 4) Further ties are broken by picking the highest pid. 601590Srgrimes * 611590Srgrimes * If you change this, be sure to consider making the change in the kernel 621590Srgrimes * too (^T in kern/tty.c). 631590Srgrimes * 641590Srgrimes * TODO - consider whether pctcpu should be used. 651590Srgrimes */ 661590Srgrimes 6787674Smarkm#include <sys/cdefs.h> 6887674Smarkm 6987674Smarkm__FBSDID("$FreeBSD: head/usr.bin/w/proc_compare.c 97981 2002-06-07 01:41:54Z jmallett $"); 7087674Smarkm 7169896Smckusick#define ISRUN(p) (((p)->ki_stat == SRUN) || ((p)->ki_stat == SIDL)) 721590Srgrimes#define TESTAB(a, b) ((a)<<1 | (b)) 731590Srgrimes#define ONLYA 2 741590Srgrimes#define ONLYB 1 751590Srgrimes#define BOTH 3 761590Srgrimes 771590Srgrimesint 7897981Sjmallettproc_compare(struct kinfo_proc *p1, struct kinfo_proc *p2) 791590Srgrimes{ 801590Srgrimes 811590Srgrimes if (p1 == NULL) 821590Srgrimes return (1); 831590Srgrimes /* 841590Srgrimes * see if at least one of them is runnable 851590Srgrimes */ 861590Srgrimes switch (TESTAB(ISRUN(p1), ISRUN(p2))) { 871590Srgrimes case ONLYA: 881590Srgrimes return (0); 891590Srgrimes case ONLYB: 901590Srgrimes return (1); 911590Srgrimes case BOTH: 921590Srgrimes /* 931590Srgrimes * tie - favor one with highest recent cpu utilization 941590Srgrimes */ 9569896Smckusick if (p2->ki_estcpu > p1->ki_estcpu) 961590Srgrimes return (1); 9769896Smckusick if (p1->ki_estcpu > p2->ki_estcpu) 981590Srgrimes return (0); 9969896Smckusick return (p2->ki_pid > p1->ki_pid); /* tie - return highest pid */ 1001590Srgrimes } 1011590Srgrimes /* 1021590Srgrimes * weed out zombies 1031590Srgrimes */ 10469896Smckusick switch (TESTAB(p1->ki_stat == SZOMB, p2->ki_stat == SZOMB)) { 1051590Srgrimes case ONLYA: 1061590Srgrimes return (1); 1071590Srgrimes case ONLYB: 1081590Srgrimes return (0); 1091590Srgrimes case BOTH: 11069896Smckusick return (p2->ki_pid > p1->ki_pid); /* tie - return highest pid */ 1111590Srgrimes } 1121590Srgrimes /* 1131590Srgrimes * pick the one with the smallest sleep time 1141590Srgrimes */ 11569896Smckusick if (p2->ki_slptime > p1->ki_slptime) 1161590Srgrimes return (0); 11769896Smckusick if (p1->ki_slptime > p2->ki_slptime) 1181590Srgrimes return (1); 1191590Srgrimes /* 1201590Srgrimes * favor one sleeping in a non-interruptible sleep 1211590Srgrimes */ 12283366Sjulian if (p1->ki_tdflags & TDF_SINTR && (p2->ki_tdflags & TDF_SINTR) == 0) 1231590Srgrimes return (1); 12483366Sjulian if (p2->ki_tdflags & TDF_SINTR && (p1->ki_tdflags & TDF_SINTR) == 0) 1251590Srgrimes return (0); 12687674Smarkm return (p2->ki_pid > p1->ki_pid); /* tie - return highest pid */ 1271590Srgrimes} 128