stats: don't query battery and temp as often when using acpi

Querying battery (or temperature) using ACPI takes quite some
resources, which makes the battery discharge faster.  It doesn't make
much sense to have it queried as often either.  So, when using ACPI:

1) set battery query period to 10s minimum
2) set temperature query period to 5s minimum

1 files changed, 27 insertions, 7 deletions

diff --git a/sys/src/cmd/stats.c b/sys/src/cmd/stats.c
index ac5f9b448..e62735dc0 100644
--- a/sys/src/cmd/stats.c
+++ b/sys/src/cmd/stats.c
@@ -219,7 +219,9 @@ int	ngraph;	/* totaly number is ngraph*nmach */
 double	scale = 1.0;
 int	logscale = 0;
 int	ylabels = 0;
-int 	sleeptime = 1000;
+int	sleeptime = 1000;
+int	batteryperiod = 1000;
+int	tempperiod = 1000;
 
 char	*procnames[NPROC] = {"main", "input"};
 
@@ -625,6 +627,7 @@ initmach(Machine *m, char *name)
 	}
 	m->bitsybatfd = -1;
 	if(m->batteryfd >= 0){
+		batteryperiod = 10000;
 		if(loadbuf(m, &m->batteryfd) && readnums(m, nelem(m->batterystats), a, 0))
 			memmove(m->batterystats, a, sizeof(m->batterystats));
 	}else{
@@ -636,6 +639,7 @@ initmach(Machine *m, char *name)
 	snprint(buf, sizeof buf, "%s/dev/cputemp", mpt);
 	m->tempfd = open(buf, OREAD);
 	if(m->tempfd < 0){
+		tempperiod = 5000;
 		snprint(buf, sizeof buf, "%s/mnt/acpi/cputemp", mpt);
 		m->tempfd = open(buf, OREAD);
 	}
@@ -679,7 +683,14 @@ needether(int init)
 int
 needbattery(int init)
 {
-	return init | present[Mbattery];
+	static uint step = 0;
+
+	if(++step*sleeptime >= batteryperiod){
+		step = 0;
+		return init | present[Mbattery];
+	}
+
+	return 0;
 }
 
 int
@@ -691,7 +702,14 @@ needsignal(int init)
 int
 needtemp(int init)
 {
-	return init | present[Mtemp];
+	static uint step = 0;
+
+	if(++step*sleeptime >= tempperiod){
+		step = 0;
+		return init | present[Mtemp];
+	}
+
+	return 0;
 }
 
 void
@@ -737,10 +755,12 @@ readmach(Machine *m, int init)
 	if(needsignal(init) && loadbuf(m, &m->ifstatsfd) && strncmp(m->buf, "Signal: ", 8)==0 && readnums(m, nelem(m->netetherifstats), a, 1)){
 		memmove(m->netetherifstats, a, sizeof m->netetherifstats);
 	}
-	if(needbattery(init) && loadbuf(m, &m->batteryfd) && readnums(m, nelem(m->batterystats), a, 0))
-		memmove(m->batterystats, a, sizeof(m->batterystats));
-	if(needbattery(init) && loadbuf(m, &m->bitsybatfd) && readnums(m, 1, a, 0))
-		memmove(m->batterystats, a, sizeof(m->batterystats));
+	if(needbattery(init)){
+		if(loadbuf(m, &m->batteryfd) && readnums(m, nelem(m->batterystats), a, 0))
+			memmove(m->batterystats, a, sizeof(m->batterystats));
+		else if(loadbuf(m, &m->bitsybatfd) && readnums(m, 1, a, 0))
+			memmove(m->batterystats, a, sizeof(m->batterystats));
+	}
 	if(needtemp(init) && loadbuf(m, &m->tempfd))
 		for(n=0; n < nelem(m->temp) && readnums(m, 2, a, 0); n++)
 			 m->temp[n] = a[0];