RE: [PATCH] sched: recover sched_yield task running time increase

[Shi, Alex]

>> > NACK
>> >
>> > This was switched off by default and under
>> > the sysctl sched_compat_yield for a reason.
>> >
>> > Reintroducing it under that sysctl option
>> > may be acceptable, but by default it would
>> > be doing the wrong thing for other workloads.
>>
>> I can implement this as sysctl option. But when I checked again the man
>> page of sched_yield. I have some concerns on this.
>>
>> ----
>>        int sched_yield(void);
>>
>> DESCRIPTION
>>        A  process  can  relinquish  the processor voluntarily without blocking by calling sched_yield().
>>        The process will then be moved to the end of the queue for its static priority and a new  process
>>        gets to run.
>> ----
>>
>> If a application calls sched_yield system call, most of time it is not
>> want to be launched again right now. so the man page said "the caller
>> process will then be moved to the _end_ of the queue..."
>
>Moving a yielding nice 0 task behind a SCHED_IDLE (or nice 19) task
>could be incredibly painful.

Good reminder! Do you have more detailed idea on this? 
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