2 * Copyright (c) 2010 The DragonFly Project. All rights reserved.
4 * This code is derived from software contributed to The DragonFly Project
5 * by Matthew Dillon <dillon@backplane.com>
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in
15 * the documentation and/or other materials provided with the
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19 * from this software without specific, prior written permission.
21 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
22 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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36 * The powerd daemon monitors the cpu load and adjusts cpu frequencies
37 * via hw.acpi.cpu.px_dom*.
40 #include <sys/types.h>
41 #include <sys/sysctl.h>
42 #include <sys/kinfo.h>
50 static void usage(void);
51 static double getcputime(void);
52 static void acpi_setcpufreq(int nstate);
53 static void setupdominfo(void);
56 int CpuLimit; /* # of cpus at max frequency */
57 int DomLimit; /* # of domains at max frequency */
62 int CpuCount[256]; /* # of cpus in any given domain */
63 int CpuToDom[256]; /* domain a particular cpu belongs to */
64 double Trigger = 0.25; /* load per cpu to force max freq */
67 main(int ac, char **av)
75 while ((ch = getopt(ac, av, "d")) != -1) {
89 * Make sure powerd is not already running.
91 PowerFd = open("/var/run/powerd.pid", O_CREAT|O_RDWR, 0644);
94 "Cannot create /var/run/powerd.pid, "
95 "continuing anyway\n");
97 if (flock(PowerFd, LOCK_EX|LOCK_NB) < 0) {
98 fprintf(stderr, "powerd is already running\n");
104 * Demonize and set pid
108 openlog("powerd", LOG_CONS | LOG_PID, LOG_DAEMON);
112 ftruncate(PowerFd, 0);
113 snprintf(buf, sizeof(buf), "%d\n", (int)getpid());
114 write(PowerFd, buf, strlen(buf));
118 * Wait hw.acpi.cpu.px_dom* sysctl to be created by kernel
120 * Since hw.acpi.cpu.px_dom* creation is queued into ACPI
121 * taskqueue and ACPI taskqueue is shared across various
122 * ACPI modules, any delay in other modules may cause
123 * hw.acpi.cpu.px_dom* to be created at quite a later time
124 * (e.g. cmbat module's task could take quite a lot of time).
128 * Prime delta cputime calculation, make sure at least
135 if (DomBeg >= DomEnd) {
148 * Calculate nstate, the number of cpus we wish to run at max
149 * frequency. All remaining cpus will be set to their lowest
150 * frequency and mapped out of the user process scheduler.
154 savg = (savg * 7.0 + qavg) / 8.0;
156 nstate = savg / Trigger;
160 printf("\rqavg=%5.2f savg=%5.2f %2d/%2d ncpus=%d\r",
161 qavg, savg, CpuLimit, DomLimit, nstate);
164 if (nstate != CpuLimit)
165 acpi_setcpufreq(nstate);
171 * Figure out the domains and calculate the CpuCount[] and CpuToDom[]
185 for (i = 0; i < 256; ++i) {
186 snprintf(buf, sizeof(buf),
187 "hw.acpi.cpu.px_dom%d.available", i);
188 if (sysctlbyname(buf, NULL, NULL, NULL, 0) >= 0)
193 for (i = 255; i >= DomBeg; --i) {
194 snprintf(buf, sizeof(buf),
195 "hw.acpi.cpu.px_dom%d.available", i);
196 if (sysctlbyname(buf, NULL, NULL, NULL, 0) >= 0) {
203 for (i = DomBeg; i < DomEnd; ++i) {
204 snprintf(buf, sizeof(buf),
205 "hw.acpi.cpu.px_dom%d.members", i);
206 msize = sizeof(members);
207 if (sysctlbyname(buf, members, &msize, NULL, 0) == 0) {
209 for (str = strtok(members, " "); str;
210 str = strtok(NULL, " ")) {
212 sscanf(str, "cpu%d", &n);
224 * Return the one-second cpu load. One cpu at 100% will return a value
225 * of 1.0. On a SMP system N cpus running at 100% will return a value of N.
231 static struct kinfo_cputime ocpu_time[64];
232 static struct kinfo_cputime ncpu_time[64];
238 bcopy(ncpu_time, ocpu_time, sizeof(ncpu_time));
239 slen = sizeof(ncpu_time);
240 if (sysctlbyname("kern.cputime", &ncpu_time, &slen, NULL, 0) < 0) {
241 fprintf(stderr, "kern.cputime sysctl not available\n");
244 ncpu = slen / sizeof(ncpu_time[0]);
247 for (cpu = 0; cpu < ncpu; ++cpu) {
248 delta += (ncpu_time[cpu].cp_user + ncpu_time[cpu].cp_sys +
249 ncpu_time[cpu].cp_nice + ncpu_time[cpu].cp_intr) -
250 (ocpu_time[cpu].cp_user + ocpu_time[cpu].cp_sys +
251 ncpu_time[cpu].cp_nice + ocpu_time[cpu].cp_intr);
253 return((double)delta / 1000000.0);
257 * nstate is the requested number of cpus that we wish to run at full
258 * frequency. We calculate how many domains we have to adjust to reach
261 * This function also sets the user scheduler global cpu mask.
265 acpi_setcpufreq(int nstate)
268 int increasing = (nstate > CpuLimit);
280 cpumask_t global_cpumask;
283 * Calculate the ending domain if the number of operating cpus
286 * Calculate the starting domain if the number of operating cpus
289 for (dom = DomBeg; dom < DomEnd; ++dom) {
292 ncpus += CpuCount[dom];
295 syslog(LOG_INFO, "using %d cpus", nstate);
298 * Set the mask of cpus the userland scheduler is allowed to use.
300 global_cpumask = (1L << nstate) - 1;
301 sysctlbyname("kern.usched_global_cpumask", NULL, 0,
302 &global_cpumask, sizeof(global_cpumask));
315 * Adjust the cpu frequency
319 for (dom = domBeg; dom < domEnd; ++dom) {
321 * Retrieve availability list
323 asprintf(&sysid, "hw.acpi.cpu.px_dom%d.available", dom);
324 buflen = sizeof(buf) - 1;
325 v = sysctlbyname(sysid, buf, &buflen, NULL, 0);
332 * Parse out the highest and lowest cpu frequencies
335 highest = lowest = 0;
336 while (ptr && (v = strtol(ptr, &ptr, 10)) > 0) {
337 if (lowest == 0 || lowest > v)
339 if (highest == 0 || highest < v)
344 * Calculate the desired cpu frequency, test, and set.
346 desired = increasing ? highest : lowest;
348 asprintf(&sysid, "hw.acpi.cpu.px_dom%d.select", dom);
351 sysctlbyname(sysid, &v, &buflen, NULL, 0);
354 printf("dom%d set frequency %d\n",
357 sysctlbyname(sysid, NULL, NULL,
358 &desired, sizeof(desired));
368 fprintf(stderr, "usage: powerd [-d]\n");