[PATCH v2] doc: Clarify rate-monotonic statistics

[Joel Sherrill]

Apply it

On 12/12/2014 08:48 AM, Sebastian Huber wrote:
> ---
>   doc/user/rtmon.t | 19 +++++++++++++++----
>   1 file changed, 15 insertions(+), 4 deletions(-)
>
> diff --git a/doc/user/rtmon.t b/doc/user/rtmon.t
> index 7786e76..a816962 100644
> --- a/doc/user/rtmon.t
> +++ b/doc/user/rtmon.t
> @@ -52,10 +52,10 @@ A clock tick is required to support the functionality provided by this manager.
>
>   @subsection Period Statistics
>
> -This manager maintains a set of statistics on each period.  These
> -statistics are reset implictly at period creation time and may be
> -reset or obtained at any time by the application.  The following
> -is a list of the information kept:
> +This manager maintains a set of statistics on each period object.  These
> +statistics are reset implictly at period creation time and may be reset or
> +obtained at any time by the application.  The following is a list of the
> +information kept:
>
>   @itemize @bullet
>   @item @code{owner}
> @@ -93,6 +93,17 @@ during executions of the periodic loop.
>
>   @end itemize
>
> +Each period is divided into two consecutive phases.  The period starts with the
> +active phase of the task and is followed by the inactive phase of the task.  In
> +the inactive phase the task is blocked and waits for the start of the next
> +period.  The inactive phase is skipped in case of a period miss.  The wall time
> +includes the time during the active phase of the task on which the task is not
> +executing on a processor.  The task is either blocked (for example it waits for
> +a resource) or a higher priority tasks executes, thus preventing it from
> +executing.  In case the wall time exceeds the period time, then this is a
> +period miss.  The gap between the wall time and the period time is the margin
> +between a period miss or success.
> +
>   The period statistics information is inexpensive to maintain
>   and can provide very useful insights into the execution
>   characteristics of a periodic task loop.  But it is just information.