The unit mentioned in the documentation of scheduler statistics is
outdated which may mislead the readers.
The unit of statistics that is reported by /proc/schedstat is modified
to nanosecond, and the unit of statistics that is reported by
/proc/PID/schedstat is provided as well to make the context consistent.
The rq_cpu_time and the rq_sched_info.run_delay of a run queue, and the
sched_info.run_delay of a task are all updated based on the clock of the
run queue, while the se.sum_exec_runtime of a task is updated based on
the clock_task of the run queue of the task. Both the clock and
clock_task are relied on the return value of the function sched_clock()
which is in the unit of nanosecond.
Signed-off-by: Jui-Tse Huang <[email protected]>
---
Documentation/scheduler/sched-stats.rst | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/Documentation/scheduler/sched-stats.rst b/Documentation/scheduler/sched-stats.rst
index dd9b99a025f7..03c062915998 100644
--- a/Documentation/scheduler/sched-stats.rst
+++ b/Documentation/scheduler/sched-stats.rst
@@ -56,9 +56,9 @@ Next two are try_to_wake_up() statistics:
Next three are statistics describing scheduling latency:
- 7) sum of all time spent running by tasks on this processor (in jiffies)
+ 7) sum of all time spent running by tasks on this processor (in nanoseconds)
8) sum of all time spent waiting to run by tasks on this processor (in
- jiffies)
+ nanoseconds)
9) # of timeslices run on this cpu
@@ -155,8 +155,8 @@ schedstats also adds a new /proc/<pid>/schedstat file to include some of
the same information on a per-process level. There are three fields in
this file correlating for that process to:
- 1) time spent on the cpu
- 2) time spent waiting on a runqueue
+ 1) time spent on the cpu (in nanoseconds)
+ 2) time spent waiting on a runqueue (in nanoseconds)
3) # of timeslices run on this cpu
A program could be easily written to make use of these extra fields to
--
2.25.1
Jui-Tse Huang <[email protected]> writes:
> The unit mentioned in the documentation of scheduler statistics is
> outdated which may mislead the readers.
>
> The unit of statistics that is reported by /proc/schedstat is modified
> to nanosecond, and the unit of statistics that is reported by
> /proc/PID/schedstat is provided as well to make the context consistent.
>
> The rq_cpu_time and the rq_sched_info.run_delay of a run queue, and the
> sched_info.run_delay of a task are all updated based on the clock of the
> run queue, while the se.sum_exec_runtime of a task is updated based on
> the clock_task of the run queue of the task. Both the clock and
> clock_task are relied on the return value of the function sched_clock()
> which is in the unit of nanosecond.
>
> Signed-off-by: Jui-Tse Huang <[email protected]>
> ---
> Documentation/scheduler/sched-stats.rst | 8 ++++----
> 1 file changed, 4 insertions(+), 4 deletions(-)
Part of this had already been fixed by a previous patch, but git was
able to figure it out...this one's applied as well, thanks.
jon