System information

Tuning the Task Scheduler 175
SCHED_OTHER policy, they will all be run on the same processor. The de-
fault value is 32. Increasing this value gives a performance boost to large
SCHED_OTHER threads at the expense of increased latencies for real-time
tasks.
14.4.7 Debugging Interface and
Scheduler Statistics
CFS comes with a new improved debugging interface, and provides runtime statistics
information. Relevant files were added to the /proc file system, which can be exam-
ined simply with the cat or less command. A list of the related /proc files fol-
lows with their short description:
/proc/sched_debug
Contains the current values of all tunable variables (see Section14.4.6, “Runtime
Tuning with sysctl” (page172)) that affect the task scheduler behavior,
CFS statistics, and information about the run queue on all available processors.
saturn.example.com:~ # less /proc/sched_debug
Sched Debug Version: v0.09, 2.6.32.8-0.3-default #1
now at 2413026096.408222 msecs
.jiffies : 4898148820
.sysctl_sched_latency : 5.000000
.sysctl_sched_min_granularity : 1.000000
.sysctl_sched_wakeup_granularity : 1.000000
.sysctl_sched_child_runs_first : 0.000000
.sysctl_sched_features : 15834238
.sysctl_sched_tunable_scaling : 1 (logaritmic)
cpu#0, 1864.411 MHz
.nr_running : 1
.load : 1024
.nr_switches : 37539000
.nr_load_updates : 22950725
[...]
cfs_rq[0]:/
.exec_clock : 52940326.803842
.MIN_vruntime : 0.000001
.min_vruntime : 54410632.307072
.max_vruntime : 0.000001
[...]
rt_rq[0]:/
.rt_nr_running : 0
.rt_throttled : 0
.rt_time : 0.000000
.rt_runtime : 950.000000