the prevalence of multi-core laptops revealed that taking the cpu average is

a poor way to adjust performance.  Even with a cpu pegged, apmd is quite slow
to react.  Change things to consider min idle time, not average.
Mostly from a diff by Laurence Tratt

1 files changed, 43 insertions, 95 deletions

diff --git a/usr.sbin/apmd/apmd.c b/usr.sbin/apmd/apmd.c
index 58ad09e088f..0eedae27feb 100644
--- a/usr.sbin/apmd/apmd.c
+++ b/usr.sbin/apmd/apmd.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: apmd.c,v 1.49 2007/11/24 14:58:44 deraadt Exp $	*/
+/*	$OpenBSD: apmd.c,v 1.50 2009/02/03 01:52:49 tedu Exp $	*/
 
 /*
  *  Copyright (c) 1995, 1996 John T. Kohl
@@ -61,12 +61,15 @@ const char sockfile[] = _PATH_APM_SOCKET;
 int debug = 0;
 
 int doperf = PERF_NONE;
-#define PERFINC 50
-#define PERFDEC 20
+#define PERFINC 15
+#define PERFDEC 15
 #define PERFMIN 0
 #define PERFMAX 100
 #define PERFINCTHRES 10
 #define PERFDECTHRES 30
+#define PERFTIMEOUTERR 999999999
+#define PERFTIMEOUTFAST 10000
+#define PERFTIMEOUTSLOW 25000
 
 extern char *__progname;
 
@@ -74,9 +77,8 @@ void usage(void);
 int power_status(int fd, int force, struct apm_power_info *pinfo);
 int bind_socket(const char *sn);
 enum apm_state handle_client(int sock_fd, int ctl_fd);
-int  get_avg_idle_mp(int ncpu);
-int  get_avg_idle_up(void);
-void perf_status(struct apm_power_info *pinfo, int ncpu);
+int  get_min_idle_mp(int ncpu);
+useconds_t perf_status(struct apm_power_info *pinfo, int ncpu);
 void suspend(int ctl_fd);
 void stand_by(int ctl_fd);
 void setperf(int new_perf);
@@ -195,13 +197,12 @@ power_status(int fd, int force, struct apm_power_info *pinfo)
 
 /* multi- and uni-processor case */
 int
-get_avg_idle_mp(int ncpu)
+get_min_idle_mp(int ncpu)
 {
 	static int64_t **cp_time_old;
 	static int64_t **cp_time;
-	static int *avg_idle;
 	int64_t change, sum, idle;
-	int i, cpu, min_avg_idle;
+	int i, cpu, min_idle;
 	size_t cp_time_sz = CPUSTATES * sizeof(int64_t);
 
 	if (!cp_time_old)
@@ -212,11 +213,7 @@ get_avg_idle_mp(int ncpu)
 		if ((cp_time = calloc(sizeof(int64_t *), ncpu)) == NULL)
 			return -1;
 
-	if (!avg_idle)
-		if ((avg_idle = calloc(sizeof(int), ncpu)) == NULL)
-			return -1;
-
-	min_avg_idle = 0;
+	min_idle = 100;
 	for (cpu = 0; cpu < ncpu; cpu++) {
 		int cp_time_mib[] = {CTL_KERN, KERN_CPTIME2, cpu};
 
@@ -230,14 +227,14 @@ get_avg_idle_mp(int ncpu)
 			    calloc(sizeof(int64_t), CPUSTATES)) == NULL)
 				return -1;
 
-		if (sysctl(cp_time_mib, 3, cp_time[cpu], &cp_time_sz, NULL, 0)
-		    < 0)
+		if (sysctl(cp_time_mib, 3, cp_time[cpu], &cp_time_sz, NULL, 0))
 			syslog(LOG_INFO, "cannot read kern.cp_time2");
 
 		sum = 0;
+		idle = 100;
 		for (i = 0; i < CPUSTATES; i++) {
-			if ((change = cp_time[cpu][i] - cp_time_old[cpu][i])
-			    < 0) {
+			change = cp_time[cpu][i] - cp_time_old[cpu][i];
+			if (change < 0) {
 				/* counter wrapped */
 				change = ((uint64_t)cp_time[cpu][i] -
 				    (uint64_t)cp_time_old[cpu][i]);
@@ -249,101 +246,52 @@ get_avg_idle_mp(int ncpu)
 		if (sum == 0)
 			sum = 1;
 
-		/* smooth data */
-		avg_idle[cpu] = (avg_idle[cpu] + (100 * idle) / sum) / 2;
-
-		if (cpu == 0)
-			min_avg_idle = avg_idle[cpu];
-
-		if (avg_idle[cpu] < min_avg_idle)
-			min_avg_idle = avg_idle[cpu];
+		if ((100 * idle) / sum < min_idle)
+			min_idle = (100 * idle) / sum;
 
 		memcpy(cp_time_old[cpu], cp_time[cpu], cp_time_sz);
 	}
 
-	return min_avg_idle;
-}
-
-int
-get_avg_idle_up(void)
-{
-	static long cp_time_old[CPUSTATES];
-	static int avg_idle;
-	long change, cp_time[CPUSTATES];
-	int cp_time_mib[] = {CTL_KERN, KERN_CPTIME};
-	size_t cp_time_sz = sizeof(cp_time);
-	int i, idle, sum = 0;
-
-	if (sysctl(cp_time_mib, 2, &cp_time, &cp_time_sz, NULL, 0) < 0)
-		syslog(LOG_INFO, "cannot read kern.cp_time");
-
-	for (i = 0; i < CPUSTATES; i++) {
-		if ((change = cp_time[i] - cp_time_old[i]) < 0) {
-			/* counter wrapped */
-			change = ((unsigned long)cp_time[i] -
-			    (unsigned long)cp_time_old[i]);
-		}
-		sum += change;
-		if (i == CP_IDLE)
-			idle = change;
-	}
-	if (sum == 0)
-		sum = 1;
-
-	/* smooth data */
-	avg_idle = (avg_idle + (100 * idle) / sum) / 2;
-
-	memcpy(cp_time_old, cp_time, sizeof(cp_time_old));
-
-	return avg_idle;
+	return min_idle;
 }
 
-void
+useconds_t
 perf_status(struct apm_power_info *pinfo, int ncpu)
 {
-	int avg_idle;
+	int avg_idle, min_idle;
 	int hw_perf_mib[] = {CTL_HW, HW_SETPERF};
 	int perf;
 	int forcehi = 0;
 	size_t perf_sz = sizeof(perf);
 
-	if (ncpu > 1) {
-		avg_idle = get_avg_idle_mp(ncpu);
-	} else {
-		avg_idle = get_avg_idle_up();
-	}
-
 	if (avg_idle == -1)
-		return;
+		return PERFTIMEOUTERR;
+
+	if (sysctl(hw_perf_mib, 2, &perf, &perf_sz, NULL, 0) < 0)
+		syslog(LOG_INFO, "cannot read hw.setperf");
 
 	switch (doperf) {
 	case PERF_AUTO:
-		/*
-		 * force setperf towards the max if we are connected to AC
-		 * power and have a battery life greater than 15%
-		 */
 		if (pinfo->ac_state == APM_AC_ON && pinfo->battery_life > 15)
-			forcehi = 1;		
-		break;
+			forcehi = 1;
 	case PERF_COOL:
-		forcehi = 0;
-		break;
-	}
-	
-	if (sysctl(hw_perf_mib, 2, &perf, &perf_sz, NULL, 0) < 0)
-		syslog(LOG_INFO, "cannot read hw.setperf");
-
-	if (forcehi || (avg_idle < PERFINCTHRES && perf < PERFMAX)) {
-		perf += PERFINC;
-		if (perf > PERFMAX)
-			perf = PERFMAX;
-		setperf(perf);
-	} else if (avg_idle > PERFDECTHRES && perf > PERFMIN) {
-		perf -= PERFDEC;
-		if (perf < PERFMIN)
-			perf = PERFMIN;
-		setperf(perf);
+		min_idle = get_min_idle_mp(ncpu);
+		if (forcehi || (min_idle < PERFINCTHRES && perf < PERFMAX)) {
+			perf += PERFINC;
+			if (perf > PERFMAX)
+				perf = PERFMAX;
+			setperf(perf);
+			return PERFTIMEOUTFAST;
+		} else if (min_idle > PERFDECTHRES && perf > PERFMIN) {
+			perf -= PERFDEC;
+			if (perf < PERFMIN)
+				perf = PERFMIN;
+			setperf(perf);
+			return PERFTIMEOUTSLOW;
+		} else
+			return PERFTIMEOUTSLOW;
 	}
+	return PERFTIMEOUTSLOW;
 }
 
 char socketname[MAXPATHLEN];
@@ -645,8 +593,8 @@ main(int argc, char *argv[])
 		sts = ts;
 
 		if (doperf == PERF_AUTO || doperf == PERF_COOL) {
-			sts.tv_sec = 1;
-			perf_status(&pinfo, ncpu);
+			sts.tv_sec = 0;
+			sts.tv_nsec = perf_status(&pinfo, ncpu);
 		}
 
 		apmtimeout += sts.tv_sec;