Messages in this thread | | | Date | Mon, 27 Mar 2017 10:20:28 +0200 | From | Luca Abeni <> | Subject | Re: [RFC v5 2/9] sched/deadline: improve the tracking of active utilization |
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On Fri, 24 Mar 2017 22:31:46 -0400 Steven Rostedt <rostedt@goodmis.org> wrote:
> On Fri, 24 Mar 2017 22:47:15 +0100 > luca abeni <luca.abeni@santannapisa.it> wrote: > > > Ok... Since I am not good at ascii art, would it be ok to add a > > textual description? If yes, I'll add a comment like: > > " > > The utilization of a task is added to the runqueue's active > > utilization when the task becomes active (is enqueued in the > > runqueue), and is removed when the task becomes inactive. A task > > does not become immediately inactive when it blocks, but becomes > > inactive at the so called "0 lag time"; so, we setup the "inactive > > timer" to fire at the "0 lag time". When the "inactive timer" > > fires, the task utilization is removed from the runqueue's active > > utilization. If the task wakes up again on the same runqueue before > > the "0 lag time", the active utilization must not be changed and > > the "inactive timer" must be cancelled. If the task wakes up again > > on a different runqueue before the "0 lag time", then the task's > > utilization must be removed from the previous runqueue's active > > utilization and must be added to the new runqueue's active > > utilization. In order to avoid races between a task waking up on a > > runqueue while the "inactive timer" is running on a different CPU, > > the "dl_non_contending" flag is used to indicate that a task is not > > on a runqueue but is active (so, the flag is set when the task > > blocks and is cleared when the "inactive timer" fires or when the > > task wakes up). > > Sure, the above is great if you never want anyone to read it ;) > > Can you please break it up a little. My head starts to spin by the > third line down.
Ok... Maybe finding a clean and understandable way to explain the above sentence is something that can be done at the OSPM summit?
Thanks, Luca
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