Re: Scheduler balancing statistics

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

Rick Lindsley wrote:
> 	From an analysis standpoint it would be nice to know which of
> 	the major features are being activated for a particular load.
> 	So imbalance-driven moves, power-driven moves, and the number of
> 	times each domain tried to balance and failed would all be useful.
> 	I think your output covered those.
> 
>     It doesn't get into the finer points of how the imbalance is derived,
>     but maybe it should...
> 
> It's ok to wait and see if those are useful before implementing them. I
> suspect they would be relatively easily added if they were needed.
> One reason there are 6 versions of scheduler statistics is that the
> information needed kept changing, both due to a better understanding of
> bottlenecks and due to changing code.
> 

Yep.

>     Well, every domain that is reported here will cover the entire system
>     because it simply takes the sum of statistics from all domains.
> 
> I would suggest creating an output format that gives you all this
> information (since we have it anyway) but I think it is quite reasonable
> for the program which *interprets* this information to summarize it.
> 

OK, yeah that is a fine idea.

> 	Would you say these would be in addition to the schedstats or
> 	would these replace them?
> 
>     It will replace some of them, I think.
> 
> That's my thought too.	I would suggest that we merge them into one patch.
> Much as I'd like to see my schedstats hit the mainline, I think it
> is prudent to separate the major architectural changes sched-domains
> introduces from statistics both related and unrelated to them --
> and having two statistics patches for the scheduler, even if they are
> complementary, makes it harder on Andrew and more confusing for users.
> 

No, I started with your sources, and the plan has always
been to merge my changes back to you where possible.