Re: [RFC PATCH] sched: Add cpu based entries to debugfs

[David Ahern <david.ahern@oracle.com>]

On 3/31/15 3:13 AM, Ingo Molnar wrote:
>
> * Peter Zijlstra <peterz@infradead.org> wrote:
>
>> On Mon, Mar 30, 2015 at 10:43:14AM +0200, Mike Galbraith wrote:
>>
>>> I think it would be a good thing if we can get away with it, but I
>>> also think you could safely bet your life that somebody will
>>> squeak.
>>
>> The thing I worry most about is that squeaking only happening 5
>> years later :/
>
> So lets start by keeping the sysctl thing with the very
> scheduler-internal names, but all zeroes and no effect of any change -
> i.e. a dead API in all but appearance. I don't think there's any
> legitimate use of those, beyond debugging, as we could change the
> internal implementation anymore and moot many of those flags.
>
> So lets trigger the squeaking that way. If any complaint comes in
> beyond 1-2 kernel releases then I don't think it's a regression, it
> turns into a feature request ...

Sorry to be so dense but I am not clear on what is acceptable and not. 
As mentioned in a previous response, these are the scheduler related 
files I am aware of:

- debufs file for sched_features (/sys/kernel/debug/sched_features)

- /proc/sys/kernel/sched_domain for tweaking scheduling parameters

- /proc/sched_debug - various internal stats

- /sys/devices/system/cpu entries. e.g., for cpu topology (physical 
package id, core id, sibling cores and threads)

None of them show the sched_domain information which is the subject of 
this patch.

Can someone clarify on the duplication concerns and such?

Thanks,
David