Hi,
with dynticks and highres_timers enabled, cpufreq_ondemand makes mess here on
an AMD64 UP.
cpufreq_ondemand assumes that jiffies advance at exactly the same pace as the
sum of all kstat_cpu(cpu).cpustat.* members.
This isn't the case here as dmesg output from patch below shows.
Is cpufreq_ondemand correct assuming
"jiffies advance at exactly the same pace as the
sum of all kstat_cpu(cpu).cpustat.* members"?
Or is "dynticks and highres_timers"'s behaviour of incrementing the
sum of kstat_cpu(cpu).cpustat.* members faster than jiffies?
Karsten
diff -pur rc6-mm2/drivers/cpufreq/cpufreq_ondemand.c rc6-mm2-kw/drivers/cpufreq/cpufreq_ondemand.c
--- rc6-mm2/drivers/cpufreq/cpufreq_ondemand.c 2007-01-29 10:40:39.000000000 +0100
+++ rc6-mm2-kw/drivers/cpufreq/cpufreq_ondemand.c 2007-01-29 11:37:08.000000000 +0100
@@ -370,7 +370,15 @@ static void dbs_check_cpu(struct cpu_dbs
if (tmp_idle_ticks < idle_ticks)
idle_ticks = tmp_idle_ticks;
}
- load = (100 * (total_ticks - idle_ticks)) / total_ticks;
+ if (total_ticks < idle_ticks) {
+ static bool did;
+ if (!did) {
+ printk(KERN_INFO"%s: t%u < i%u\n", __FUNCTION__, total_ticks, idle_ticks);
+ did = true;
+ }
+ load = 0;
+ } else
+ load = (100 * (total_ticks - idle_ticks)) / total_ticks;
/* Check for frequency increase */
if (load > dbs_tuners_ins.up_threshold) {
-
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