Date: Wed, 05 Nov 2008 22:57:55 +0200 From: Alexander Motin <mav@FreeBSD.org> To: freebsd-mobile@FreeBSD.org Subject: RFC: powerd algorithms enhancements Message-ID: <491208D3.2050901@FreeBSD.org>
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Hi.
I would like to propose the patch for powerd that fixes some issues,
makes it more universal and on my opinion more usable. The main ideas of
mine were:
1. To make it more SMP polite. Previous version uses average CPU load
that leads to the often load underestimation. It make powerd with
default configuration unusable on systems with more then 2 CPUs. I
propose to use summary load instead of average one. IMO this is the best
we can do without specially tuned scheduler. Also as soon as measuring
total load on SMP systems is more useful then total idle, I have
switched to it.
2. To make powerd's operation independent from number and size of
frequency levels I have added internal frequency counter which
translated into real frequencies only on a last stage and only as good
as gone. Some systems may have only several power levels, while mine has
17 of them, so adaptation time in completely different. It would be good
if algorithm was not depending on it.
3. As part of previous I have changed adaptive mode to rise frequency on
demand up to 2 times and fall on 1/8 per time internal.
4. For desktop (AC-powered) systems I have added one more mode -
"hiadaptive". It rises frequency twice faster, drops it 4 times slower,
prefers twice lower CPU load and has additional delay before leaving the
highest frequency after the period of maximum load. This mode was
specially made to improve interactivity of the systems where operation
capabilities are more significant then power consumption, but keeping
maximum frequency all the time is not needed.
5. I have reduced polling interval from 1/2 to 1/4 of second. It is not
important for algorithm math now, but gives better system interactivity.
--
Alexander Motin
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Content-Type: text/plain;
name="powerd.c.hadp.patch"
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Content-Disposition: inline;
filename="powerd.c.hadp.patch"
--- powerd.c.prev 2008-07-29 21:51:52.000000000 +0300
+++ powerd.c 2008-11-05 22:51:35.000000000 +0200
@@ -50,13 +50,14 @@ __FBSDID("$FreeBSD: src/usr.sbin/powerd/
#include <machine/apm_bios.h>
#endif
-#define DEFAULT_ACTIVE_PERCENT 65
-#define DEFAULT_IDLE_PERCENT 90
-#define DEFAULT_POLL_INTERVAL 500 /* Poll interval in milliseconds */
+#define DEFAULT_ACTIVE_PERCENT 75
+#define DEFAULT_IDLE_PERCENT 50
+#define DEFAULT_POLL_INTERVAL 250 /* Poll interval in milliseconds */
typedef enum {
MODE_MIN,
MODE_ADAPTIVE,
+ MODE_HIADAPTIVE,
MODE_MAX,
} modes_t;
@@ -77,7 +78,7 @@ const char *modes[] = {
#define DEVDPIPE "/var/run/devd.pipe"
#define DEVCTL_MAXBUF 1024
-static int read_usage_times(long *idle, long *total);
+static int read_usage_times(int *load);
static int read_freqs(int *numfreqs, int **freqs, int **power);
static int set_freq(int freq);
static void acline_init(void);
@@ -89,7 +90,7 @@ static void parse_mode(char *arg, int *m
static void usage(void);
/* Sysctl data structures. */
-static int cp_time_mib[2];
+static int cp_times_mib[2];
static int freq_mib[4];
static int levels_mib[4];
static int acline_mib[3];
@@ -119,27 +120,49 @@ static int devd_pipe = -1;
static struct timeval tried_devd;
static int
-read_usage_times(long *idle, long *total)
+read_usage_times(int *load)
{
- static long idle_old, total_old;
- long cp_time[CPUSTATES], i, total_new;
- size_t cp_time_len;
- int error;
+ static long *cp_times = NULL, *cp_times_old = NULL;
+ static int ncpus = 0;
+ size_t cp_times_len;
+ int error, cpu, i, total;
+
+ if (cp_times == NULL) {
+ cp_times_len = 0;
+ error = sysctl(cp_times_mib, 2, NULL, &cp_times_len, NULL, 0);
+ if (error)
+ return (error);
+ if ((cp_times = malloc(cp_times_len)) == NULL)
+ return (errno);
+ if ((cp_times_old = malloc(cp_times_len)) == NULL) {
+ free(cp_times);
+ cp_times = NULL;
+ return (errno);
+ }
+ ncpus = cp_times_len / (sizeof(long) * CPUSTATES);
+ }
- cp_time_len = sizeof(cp_time);
- error = sysctl(cp_time_mib, 2, cp_time, &cp_time_len, NULL, 0);
+ cp_times_len = sizeof(long) * CPUSTATES * ncpus;
+ error = sysctl(cp_times_mib, 2, cp_times, &cp_times_len, NULL, 0);
if (error)
return (error);
- for (total_new = 0, i = 0; i < CPUSTATES; i++)
- total_new += cp_time[i];
-
- if (idle)
- *idle = cp_time[CP_IDLE] - idle_old;
- if (total)
- *total = total_new - total_old;
+
+ if (load) {
+ *load = 0;
+ for (cpu = 0; cpu < ncpus; cpu++) {
+ total = 0;
+ for (i = 0; i < CPUSTATES; i++) {
+ total += cp_times[cpu * CPUSTATES + i] -
+ cp_times_old[cpu * CPUSTATES + i];
+ }
+ if (total == 0)
+ continue;
+ *load += 100 - (cp_times[cpu * CPUSTATES + CP_IDLE] -
+ cp_times_old[cpu * CPUSTATES + CP_IDLE]) * 100 / total;
+ }
+ }
- idle_old = cp_time[CP_IDLE];
- total_old = total_new;
+ memcpy(cp_times_old, cp_times, cp_times_len);
return (0);
}
@@ -190,6 +213,21 @@ read_freqs(int *numfreqs, int **freqs, i
}
static int
+get_freq(void)
+{
+ size_t len;
+ int curfreq;
+
+ len = sizeof(curfreq);
+ if (sysctl(freq_mib, 4, &curfreq, &len, NULL, 0) != 0) {
+ if (vflag)
+ warn("error reading current CPU frequency");
+ curfreq = 0;
+ }
+ return (curfreq);
+}
+
+static int
set_freq(int freq)
{
@@ -201,6 +239,19 @@ set_freq(int freq)
return (0);
}
+static int
+get_freq_id(int freq, int *freqs, int numfreqs)
+{
+ int i = 1;
+
+ while (i < numfreqs) {
+ if (freqs[i] < freq)
+ break;
+ i++;
+ }
+ return (i - 1);
+}
+
/*
* Try to use ACPI to find the AC line status. If this fails, fall back
* to APM. If nothing succeeds, we'll just run in default mode.
@@ -341,6 +392,8 @@ parse_mode(char *arg, int *mode, int ch)
*mode = MODE_MAX;
else if (strcmp(arg, "adaptive") == 0 || strcmp(arg, "adp") == 0)
*mode = MODE_ADAPTIVE;
+ else if (strcmp(arg, "hiadaptive") == 0 || strcmp(arg, "hadp") == 0)
+ *mode = MODE_HIADAPTIVE;
else
errx(1, "bad option: -%c %s", (char)ch, optarg);
}
@@ -369,14 +422,14 @@ main(int argc, char * argv[])
int nfds;
struct pidfh *pfh = NULL;
const char *pidfile = NULL;
- long idle, total;
- int curfreq, *freqs, i, *mwatts, numfreqs;
+ int freq, curfreq, *freqs, i, j, *mwatts, numfreqs, load;
int ch, mode, mode_ac, mode_battery, mode_none;
uint64_t mjoules_used;
size_t len;
/* Default mode for all AC states is adaptive. */
- mode_ac = mode_battery = mode_none = MODE_ADAPTIVE;
+ mode_ac = mode_none = MODE_HIADAPTIVE;
+ mode_battery = MODE_ADAPTIVE;
cpu_running_mark = DEFAULT_ACTIVE_PERCENT;
cpu_idle_mark = DEFAULT_IDLE_PERCENT;
poll_ival = DEFAULT_POLL_INTERVAL;
@@ -418,7 +471,7 @@ main(int argc, char * argv[])
break;
case 'r':
cpu_running_mark = atoi(optarg);
- if (cpu_running_mark < 0 || cpu_running_mark > 100) {
+ if (cpu_running_mark <= 0 || cpu_running_mark > 100) {
warnx("%d is not a valid percent",
cpu_running_mark);
usage();
@@ -438,8 +491,8 @@ main(int argc, char * argv[])
/* Look up various sysctl MIBs. */
len = 2;
- if (sysctlnametomib("kern.cp_time", cp_time_mib, &len))
- err(1, "lookup kern.cp_time");
+ if (sysctlnametomib("kern.cp_times", cp_times_mib, &len))
+ err(1, "lookup kern.cp_times");
len = 4;
if (sysctlnametomib("dev.cpu.0.freq", freq_mib, &len))
err(1, "lookup freq");
@@ -447,8 +500,8 @@ main(int argc, char * argv[])
if (sysctlnametomib("dev.cpu.0.freq_levels", levels_mib, &len))
err(1, "lookup freq_levels");
- /* Check if we can read the idle time and supported freqs. */
- if (read_usage_times(NULL, NULL))
+ /* Check if we can read the load and supported freqs. */
+ if (read_usage_times(NULL))
err(1, "read_usage_times");
if (read_freqs(&numfreqs, &freqs, &mwatts))
err(1, "error reading supported CPU frequencies");
@@ -483,6 +536,9 @@ main(int argc, char * argv[])
signal(SIGINT, handle_sigs);
signal(SIGTERM, handle_sigs);
+ freq = get_freq();
+ if (freq < 1)
+ freq = 1;
/* Main loop. */
for (;;) {
FD_ZERO(&fdset);
@@ -522,37 +578,30 @@ main(int argc, char * argv[])
}
/* Read the current frequency. */
- len = sizeof(curfreq);
- if (sysctl(freq_mib, 4, &curfreq, &len, NULL, 0) != 0) {
- if (vflag)
- warn("error reading current CPU frequency");
+ if ((curfreq = get_freq()) == 0)
continue;
- }
+ i = get_freq_id(curfreq, freqs, numfreqs);
+
if (vflag) {
- for (i = 0; i < numfreqs; i++) {
- if (freqs[i] == curfreq)
- break;
- }
-
/* Keep a sum of all power actually used. */
- if (i < numfreqs && mwatts[i] != -1)
+ if (mwatts[i] != -1)
mjoules_used +=
(mwatts[i] * (poll_ival / 1000)) / 1000;
}
/* Always switch to the lowest frequency in min mode. */
if (mode == MODE_MIN) {
- if (curfreq != freqs[numfreqs - 1]) {
+ freq = freqs[numfreqs - 1];
+ if (curfreq != freq) {
if (vflag) {
printf("now operating on %s power; "
"changing frequency to %d MHz\n",
- modes[acline_status],
- freqs[numfreqs - 1]);
+ modes[acline_status], freq);
}
- if (set_freq(freqs[numfreqs - 1]) != 0) {
+ if (set_freq(freq) != 0) {
warn("error setting CPU freq %d",
- freqs[numfreqs - 1]);
+ freq);
continue;
}
}
@@ -561,16 +610,16 @@ main(int argc, char * argv[])
/* Always switch to the highest frequency in max mode. */
if (mode == MODE_MAX) {
- if (curfreq != freqs[0]) {
+ freq = freqs[0];
+ if (curfreq != freq) {
if (vflag) {
printf("now operating on %s power; "
"changing frequency to %d MHz\n",
- modes[acline_status],
- freqs[0]);
+ modes[acline_status], freq);
}
- if (set_freq(freqs[0]) != 0) {
+ if (set_freq(freq) != 0) {
warn("error setting CPU freq %d",
- freqs[0]);
+ freq);
continue;
}
}
@@ -578,44 +627,59 @@ main(int argc, char * argv[])
}
/* Adaptive mode; get the current CPU usage times. */
- if (read_usage_times(&idle, &total)) {
+ if (read_usage_times(&load)) {
if (vflag)
warn("read_usage_times() failed");
continue;
}
-
- /*
- * If we're idle less than the active mark, bump up two levels.
- * If we're idle more than the idle mark, drop down one level.
- */
- for (i = 0; i < numfreqs - 1; i++) {
- if (freqs[i] == curfreq)
- break;
- }
- if (idle < (total * cpu_running_mark) / 100 &&
- curfreq < freqs[0]) {
- i -= 2;
- if (i < 0)
- i = 0;
- if (vflag) {
- printf("idle time < %d%%, increasing clock"
- " speed from %d MHz to %d MHz\n",
- cpu_running_mark, curfreq, freqs[i]);
+
+ if (mode == MODE_ADAPTIVE) {
+ if (load > cpu_running_mark) {
+ if (load > 95 || load > cpu_running_mark * 2)
+ freq *= 2;
+ else
+ freq = freq * load / cpu_running_mark;
+ if (freq > freqs[0])
+ freq = freqs[0];
+ } else if (load < cpu_idle_mark &&
+ curfreq * load < freqs[get_freq_id(
+ freq * 7 / 8, freqs, numfreqs)] *
+ cpu_running_mark) {
+ freq = freq * 7 / 8;
+ if (freq < freqs[numfreqs - 1])
+ freq = freqs[numfreqs - 1];
}
- if (set_freq(freqs[i]))
- warn("error setting CPU frequency %d",
- freqs[i]);
- } else if (idle > (total * cpu_idle_mark) / 100 &&
- curfreq > freqs[numfreqs - 1]) {
- i++;
+ } else { /* MODE_HIADAPTIVE */
+ if (load > cpu_running_mark / 2) {
+ if (load > 95 || load > cpu_running_mark)
+ freq *= 4;
+ else
+ freq = freq * load * 2 / cpu_running_mark;
+ if (freq > freqs[0] * 2)
+ freq = freqs[0] * 2;
+ } else if (load < cpu_idle_mark / 2 &&
+ curfreq * load < freqs[get_freq_id(
+ freq * 31 / 32, freqs, numfreqs)] *
+ cpu_running_mark / 2) {
+ freq = freq * 31 / 32;
+ if (freq < freqs[numfreqs - 1])
+ freq = freqs[numfreqs - 1];
+ }
+ }
+ if (vflag) {
+ printf("load %3d%%, current freq %4d MHz (%2d), wanted freq %4d MHz\n",
+ load, curfreq, i, freq);
+ }
+ j = get_freq_id(freq, freqs, numfreqs);
+ if (i != j) {
if (vflag) {
- printf("idle time > %d%%, decreasing clock"
+ printf("changing clock"
" speed from %d MHz to %d MHz\n",
- cpu_idle_mark, curfreq, freqs[i]);
+ freqs[i], freqs[j]);
}
- if (set_freq(freqs[i]) != 0)
+ if (set_freq(freqs[j]))
warn("error setting CPU frequency %d",
- freqs[i]);
+ freqs[j]);
}
}
free(freqs);
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