Re: bug in sched.c:activate_task()

[Nick Piggin <nickpiggin@yahoo.com.au>]

Con Kolivas wrote:
> Ingo Molnar writes:
> 
>>
>> On Tue, 5 Oct 2004, Con Kolivas wrote:
>>
>>>     unsigned long long delta = now - next->timestamp;
>>>
>>>     if (next->activated == 1)
>>>         delta = delta * (ON_RUNQUEUE_WEIGHT * 128 / 100) / 128;
>>>
>>> is in schedule() before we update the timestamp, no?
>>
>>
>> indeed ... so the patch is just random incorrect damage that happened to
>> distrub the scheduler fixing some balancing problem. Kenneth, what
>> precisely is the balancing problem you are seeing?
> 
> 
> We used to compare jiffy difference in can_migrate_task by comparing it to
> cache_decay_ticks. Somewhere in the merging of sched_domains it was 
> changed to task_hot which uses timestamp.
> 

It always used ->timestamp though, even when that was in jiffies.
sched domains didn't change anything there (and IIRC it used
task_hot before sched domains).