cpud.c

控制CPU的linux程序cpud、cpuctl

/*
 * Copyright (c) 2004 Alf Schlichting [e-mail]
 * Copyright (c) 2004 Laurence Tratt
 * http://tratt.net/laurie/
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR OR HIS EMPLOYER BE LIABLE FOR ANY DIRECT,
 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include <sys/types.h>
#include <sys/param.h>
#include <sys/stat.h>
#include <sys/un.h>
#include <fcntl.h>

#include <sys/sysctl.h>
#include <sys/dkstat.h>
#include <sys/socket.h>

#include <string.h>
#include <poll.h>
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <math.h>
#include <err.h>
#include <errno.h>
#include <time.h>
#include <syslog.h>
#include <stdarg.h>
#include <sys/ioctl.h>
#include <machine/apmvar.h>

#include "common.h"
#include "pathnames.h"
#include "util.h"


/* This value is the threshold CPU utilization has to reach to force cpud
   to increase system performance; if CPU utilization falls below this value
   then system performance is decreased. */

#define ACTIVITY_THRESHOLD 80

/* This is the value that hw.setperf is incremented when necessary. */

#define PERF_INCREMENT 15

/* This is the value that hw.setperf is decremented when necessary. */

#define PERF_DECREMENT 15

/* Sleep interval is in microseconds. */

#define SLEEP_INTERVAL 50000

/* setperf can sometimes return an incorrect figure (e.g. after a machine has
   woken from hibernation, the hardware may put the processor in high power
   mode, but setperf may still be set to 0). Every n cycles we update setperf
   regardless of what value it claims to be. */

#define FORCE_SET_PERF_UPDATE 20

/* APM check is only exceuted every n cycles. */

#define APM_CHECK_INTERVAL 25

int debug = 0;
extern char *__progname;

void usage(void);
static int 	create_socket(char *);

void
usage(void)
{
    fprintf(stderr, "usage: %s [-d]\n", __progname);
    exit(1);
}

static int
create_socket(char *path)
{
	int s;
	struct sockaddr_un sun;

	if ((s = socket(AF_UNIX, SOCK_STREAM, 0)) == -1)
		err(1, "socket()");

	memset(&sun, 0, sizeof (sun));
	sun.sun_family = AF_UNIX;

	if (strlcpy(sun.sun_path, path, sizeof (sun.sun_path)) >=
	    sizeof (sun.sun_path))
		errx(1, "Path too long: %s", path);

	if (bind(s, (struct sockaddr*) &sun, sizeof(sun)) == -1)
		err(1, "bind()");

 	if (chmod(path, S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP) == -1) 
 		err(1, "chmod()"); 

	if (listen(s, 5) == -1)
		err(1, "listen()");

	return s;
}

int
main(int argc, char *argv[])
{
	struct perf_command 	*pc_new, *pc_cur;
	struct apm_power_info 	 apm_info;
	char 			 line[SOCKET_LINE_LEN]; /* socket read buf   */
	char			*sockpath;
	static int cp_time_mib[] = {CTL_KERN, KERN_CPTIME};
	static int hw_perf_mib[] = {CTL_HW, HW_SETPERF};
	long 			 cp_time[CPUSTATES];
	long			 cp_idletime_old,  diff;
	size_t 			 size;
	uid_t			 uid;
	gid_t			 gid;
	int			 max_perf, new_perf, perf, next_apm_check;
	int			 active;
	int			 fcn_val;		/* fcntl value 	     */
	int			 next_forced_setperf;
	int			 scheme_isset;	       /* do we have a scheme*/
	int			 treshhold;	/* When to change cpu_rate   */
	int			 stepup, stepdown;	/* how much change   */
	int			 sleeptime;		/* loop sleep value  */
	int 			 is_said;		/* did we tell syslog*/
    	int 			 ch, fd, fds, s, r, plen;

	/* Initialize pc_cur in case we are asked for our current scheme when
	*  we haven't loaded one
	*/

	sockpath                = PATH_CPUD_UNIX_SOCKET;
	pc_cur 			= calloc(1, sizeof(struct perf_command));
	pc_new 			= NULL;
	plen 			= sizeof(struct perf_command);
	/* Force APM's state to be read on the first iteration */
	next_apm_check 		= 0;
	sleeptime		= SLEEP_INTERVAL;
	treshhold		= ACTIVITY_THRESHOLD;
	stepup			= PERF_INCREMENT;
	stepdown		= PERF_DECREMENT;
	max_perf 		= 100;
	is_said			= 0;
	scheme_isset		= 0;
	next_forced_setperf 	= FORCE_SET_PERF_UPDATE;

    	while ((ch = getopt(argc, argv, "d")) != -1) {
       		switch(ch) {
       	     	case 'd':
             		debug = 1; 
                	break;
                case '?':
            	default:
               		usage();
        	}
    	}

	size = sizeof(cp_time);

	if (sysctl(cp_time_mib, 2, &cp_time, &size, NULL, 0) < 0)
		err(1, "sysctl kern.cp_time failed");

	cp_idletime_old = cp_time[CP_IDLE];

	if ((fd = open(PATH_APM_NORMAL, O_RDONLY)) == -1)
		err(1, "opening /dev/apm failed");

	s = create_socket(sockpath);

	if ((fcn_val = fcntl(s, F_GETFL, O_NONBLOCK)) == -1)
		err(1, NULL);

	if (fcntl(s, F_SETFL, fcn_val | O_NONBLOCK) == -1)
		err(1, "Couldn't set socket to NONBLOCK mode");

	if (!debug) {
		daemon(0, 1);
		openlog("cpud", LOG_PID, LOG_DAEMON);
		syslog(LOG_INFO, "starting...");
	}

	for (;;) {
		usleep(sleeptime);

		if ((fds = accept(s, NULL, NULL)) == -1) {
			if (errno != EAGAIN) {
				syslog(LOG_ERR, "accept failed: %m");
				exit(1);
			}
		} else {
			if ((r = read_sock(fds, line, plen)) != plen) {
				syslog(LOG_ERR, "read failed: %m, exiting");
				exit(1);
			}

			if (debug)
				fprintf(stdout, "cpud: read %d bytes\n", r);
			else {
				getpeereid(fds, &uid, &gid);
				syslog(LOG_INFO, "Connection from UID %d: "
					"GID %d",\
				       uid, gid);
			}
			pc_new = (struct perf_command *)line;

			if (pc_new->command == SET_SCHEME) {
				memcpy(pc_cur, pc_new, plen);

				scheme_isset = 1;

				stepup = pc_cur->s.stepup;
				stepdown = pc_cur->s.stepdown;
				sleeptime = pc_cur->s.sleep;
				treshhold = pc_cur->s.treshhold;
				syslog(LOG_INFO, "Loaded scheme %s",          \
				       pc_cur->s.name);
			} else {
				if ((r = write_sock(fds, (char *)pc_cur,      \
						    plen)) != plen) {
					if (debug)
						warn("write");
					syslog(LOG_ERR, 		      \
					       "write failed: %m, exiting");
					exit(1);
				}
			}
		}

		/* Look if we have a scheme else do nothing	*/

		if (!scheme_isset)
			continue;

		/* Checking the APM state is an expensive operation which we
		*  only do every APM_CHECK_INTERVAL cycles.
		*/

		if (next_apm_check == 0) {
			if (ioctl(fd, APM_IOC_GETPOWER, &apm_info) == -1) {
				syslog(LOG_WARNING, "ioctl apm failed");
				continue;
			}
			next_apm_check = APM_CHECK_INTERVAL;
		} else {
			next_apm_check -= 1;
		}
		if (apm_info.ac_state == APM_AC_ON) {
			if (apm_info.battery_state == APM_BATT_CHARGING)
				new_perf = pc_cur->s.ac_con_charging.\
					cpu_rate_full_power;
			else
				new_perf = pc_cur->s.ac_con.cpu_rate_full_power;
		} else {
			if (apm_info.battery_life >= pc_cur->                \
				s.ac_discon.borderline) {
			       		max_perf = pc_cur->		     \
					s.ac_discon.cpu_rate_full_power;
					is_said = 0;
			} else {
				max_perf = pc_cur->			     \
					s.ac_discon.cpu_rate_low_power;
				if (!is_said) {
					syslog(LOG_INFO, "Reached borderline "
					"at %d%%: Switching to %d",          \
					pc_cur->s.ac_discon.borderline,      \
						max_perf);
					is_said = 1;
				}
			}
		}

		size = sizeof(int);
		if (sysctl(hw_perf_mib, 2, &perf, &size, NULL, 0) < 0) {
			syslog(LOG_WARNING, "sysctl hw.setperf failed");
			continue;
		}

		new_perf = perf;

	/*  Read the processor stats. */

		size = sizeof(cp_time);

		if (sysctl(cp_time_mib, 2, &cp_time, &size, NULL, 0) < 0) {
			syslog(LOG_WARNING, "sysctl kern.cp_time failed");
			continue;
		}

	/* active is set to the percentage of processor time spent perfoming
	* any kind of activity since the last time we polled.
	*/
		diff = (cp_time[CP_IDLE] - cp_idletime_old);

		if (diff == 0)
			active = 100;
		else
			active = 100 - (((diff * 1000 + (diff / 2l)) /        \
					 diff) / 10);

		cp_idletime_old = cp_time[CP_IDLE];

		if (active > treshhold)
			new_perf = perf + stepup;
		else if (active < treshhold)
			new_perf = perf - stepdown;

	/* Enforce the upper and lower bounds. */

		if (new_perf < 0)
			new_perf = 0;
		else if (new_perf > max_perf)
			new_perf = max_perf;

        /* Because we can't always trust the value given to us for setperf,
	*  every FORCE_SET_PERF_UPDATE cycles we forcibly update its value,
	*  even if we don't think it's changed.
	*/

		next_forced_setperf--;

		if (new_perf == perf && next_forced_setperf > 0)
			continue;
		else if (next_forced_setperf == 0)
			next_forced_setperf = FORCE_SET_PERF_UPDATE;

		if (debug)
			fprintf(stderr, "setting perf to %d from %d [max %d]\n",
				new_perf, perf, max_perf);

		size = sizeof(int);

		if (sysctl(hw_perf_mib, 2, &perf, &size, &new_perf, \
			sizeof(int)) < 0) {
			syslog(LOG_WARNING, "sysctl hw.setperf failed");
			continue;
		}
	}
}