[CPUFREQ] Resolve time unit thinko in ondemand/conservative govs
Pallipadi, Venkatesh [Thu, 12 Nov 2009 00:50:29 +0000 (16:50 -0800)]
ondemand and conservative governors are messing up time units in the
code path where NO_HZ is not enabled and ignore_nice is set. The walltime
idletime stored is in jiffies and nice time calculation is happening in
microseconds.

The problem was reported and diagnosed by Alexander here.
http://marc.info/?l=linux-kernel&m=125752550404513&w=2

The patch below fixes this thinko.

Reported-by: Alexander Miller <Miller@fmi.uni-stuttgart.de>
Tested-by: Alexander Miller <Miller@fmi.uni-stuttgart.de>
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Dave Jones <davej@redhat.com>

drivers/cpufreq/cpufreq_conservative.c
drivers/cpufreq/cpufreq_ondemand.c

index bc33ddc..c7b081b 100644 (file)
@@ -116,9 +116,9 @@ static inline cputime64_t get_cpu_idle_time_jiffy(unsigned int cpu,
 
        idle_time = cputime64_sub(cur_wall_time, busy_time);
        if (wall)
-               *wall = cur_wall_time;
+               *wall = (cputime64_t)jiffies_to_usecs(cur_wall_time);
 
-       return idle_time;
+       return (cputime64_t)jiffies_to_usecs(idle_time);;
 }
 
 static inline cputime64_t get_cpu_idle_time(unsigned int cpu, cputime64_t *wall)
index 071699d..4b34ade 100644 (file)
@@ -133,9 +133,9 @@ static inline cputime64_t get_cpu_idle_time_jiffy(unsigned int cpu,
 
        idle_time = cputime64_sub(cur_wall_time, busy_time);
        if (wall)
-               *wall = cur_wall_time;
+               *wall = (cputime64_t)jiffies_to_usecs(cur_wall_time);
 
-       return idle_time;
+       return (cputime64_t)jiffies_to_usecs(idle_time);
 }
 
 static inline cputime64_t get_cpu_idle_time(unsigned int cpu, cputime64_t *wall)