Freq sysctls are quite heavy due to set of malloc()/free() calls. Avoid

reading current frequency on every period. Instead do it only after
changing and periodically from time to time if somebody else change it.

Also dynamically decrease sampling frequency up to 4 times on inactivity,

1 files changed, 21 insertions, 9 deletions

diff --git a/usr.sbin/powerd/powerd.c b/usr.sbin/powerd/powerd.c
index b4ba05d7a963..7192bddbbe95 100644
--- a/usr.sbin/powerd/powerd.c
+++ b/usr.sbin/powerd/powerd.c
@@ -435,7 +435,7 @@ main(int argc, char * argv[])
 	struct pidfh *pfh = NULL;
 	const char *pidfile = NULL;
 	int freq, curfreq, initfreq, *freqs, i, j, *mwatts, numfreqs, load;
-	int ch, mode, mode_ac, mode_battery, mode_none;
+	int ch, mode, mode_ac, mode_battery, mode_none, idle, to;
 	uint64_t mjoules_used;
 	size_t len;
 
@@ -548,9 +548,11 @@ main(int argc, char * argv[])
 	signal(SIGINT, handle_sigs);
 	signal(SIGTERM, handle_sigs);
 
-	freq = initfreq = get_freq();
+	freq = initfreq = curfreq = get_freq();
+	i = get_freq_id(curfreq, freqs, numfreqs);
 	if (freq < 1)
 		freq = 1;
+	idle = 0;
 	/* Main loop. */
 	for (;;) {
 		FD_ZERO(&fdset);
@@ -560,8 +562,14 @@ main(int argc, char * argv[])
 		} else {
 			nfds = 0;
 		}
-		timeout.tv_sec = poll_ival / 1000000;
-		timeout.tv_usec = poll_ival % 1000000;
+		if (mode == MODE_HIADAPTIVE || idle < 120)
+			to = poll_ival;
+		else if (idle < 360)
+			to = poll_ival * 2;
+		else
+			to = poll_ival * 4;
+		timeout.tv_sec = to / 1000000;
+		timeout.tv_usec = to % 1000000;
 		select(nfds, &fdset, NULL, &fdset, &timeout);
 
 		/* If the user requested we quit, print some statistics. */
@@ -590,11 +598,12 @@ main(int argc, char * argv[])
 		}
 
 		/* Read the current frequency. */
-		if ((curfreq = get_freq()) == 0)
-			continue;
-
-		i = get_freq_id(curfreq, freqs, numfreqs);
-	
+		if (idle % 32 == 0) {
+			if ((curfreq = get_freq()) == 0)
+				continue;
+			i = get_freq_id(curfreq, freqs, numfreqs);
+		}
+		idle++;
 		if (vflag) {
 			/* Keep a sum of all power actually used. */
 			if (mwatts[i] != -1)
@@ -611,6 +620,7 @@ main(int argc, char * argv[])
 					    "changing frequency to %d MHz\n",
 					    modes[acline_status], freq);
 				}
+				idle = 0;
 				if (set_freq(freq) != 0) {
 					warn("error setting CPU freq %d",
 					    freq);
@@ -629,6 +639,7 @@ main(int argc, char * argv[])
 					    "changing frequency to %d MHz\n",
 					    modes[acline_status], freq);
 				}
+				idle = 0;
 				if (set_freq(freq) != 0) {
 					warn("error setting CPU freq %d",
 				    	    freq);
@@ -689,6 +700,7 @@ main(int argc, char * argv[])
 				    " speed from %d MHz to %d MHz\n",
 				    freqs[i], freqs[j]);
 			}
+			idle = 0;
 			if (set_freq(freqs[j]))
 				warn("error setting CPU frequency %d",
 				    freqs[j]);