Re: BFS 420: cleanup in tick handling

[Hillf Danton]

On Tue, May 22, 2012 at 10:07 PM, Chen <hi3766691@xxxxxxxxx> wrote:
>
> å 2012-5-22 äå10:04ï"Hillf Danton" <dhillf@xxxxxxxxx>åéï
>
>
>>
>> On Tue, May 22, 2012 at 10:00 PM, Chen <hi3766691@xxxxxxxxx> wrote:
>> >
>> > å 2012-5-22 äå9:50ï"Hillf Danton" <dhillf@xxxxxxxxx>åéï
>> >>
>> >> On Tue, May 22, 2012 at 9:45 PM, Chen <hi3766691@xxxxxxxxx> wrote:
>> >> > Actually the lowest deadline task selection algorithm now BFS used is
>> >> > O(n).
>> >> > I have already had an idea to enhance the lowest deadline task
>> >> > selection
>> >> > algorithm to O(1)
>> >>
>> >> Would you please announce it on LKML?
>> >
>> > First of all let me talk how to do it .We can use 40 list_head instead
>> > of
>> > the single list for time sharing scheduling policy.
>> > Then for task selection we will select the task from these 40
>> > list_head(actually not 40, just decide by next_sched_bit), then make a
>> > comparsion of these tasks(actually in the worse case we just need to do
>> > 40
>> > times of comparsion) and pick the lowest task. If a task wake, it would
>> > be
>> > the first node of (queue + p->prio). If a task run out of its timeslice,
>> > it
>> > will become the last node of(queue + p->prio). This is a concept of BFS
>> > deadline presort algorithm and the time complexity is O(1)
>>
>> Thank you for shedding light, I will study it soon.
> If you are free could you also help me to maintain my cpu scheduler, thanks.
> . :-)
No promise but try my best, ok?
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