Re: [RFC][PATCH 6/6] automatic tuning applied to some kernel components

[Nadia Derbey <Nadia.Derbey@bull.net>]

Eric W. Biederman wrote:
> Nadia Derbey <Nadia.Derbey@bull.net> writes:
>
>
> > So, should I understand from this that automatic tuning and the AKT framework
> > itself would make sense, given that I find the rigth tunables it should be
> > applied to?
>
>
> Sort of.  The concept of things tuning themselves automatically makes
> a lot of sense.
>
> I'm not at all certain about tunables being exported just to be hidden
> again.  Ideally you don't even want the fact that these things are
> varying visible to the user.
>
> So I think that if you can find a good example that cannot be solved
> better another way, you can build a case for your framework.
> Currently I am doubt you can find such a case.
>
>
> > Actually, dont' know if you had the opportunity to read all the patches, but
> > there are 2 other tunables AKT is proposed to be applied to:
> > . max_threads, the tunable limit on nr_threads
> > . max_files, the tunable limit on nr_files
>
>
> At a quick glance max_threads and max_files appear even more to be
> DOS limits and not tunables and even less applicable to needing any
> tuning at all.  My gut feel is at worst these values may need a little
> better boot time defaults but otherwise they the should be good.
But, what do you do with Oracle that's asking maxfiles to be set to 
0x10000, while the default value might be enough for a system that's not 
running Oracle.
I'm afraid that giving boot time values to the max_* tunables we will 
loose all the benefits from /proc (or /sys): it is impossible to 
anticipate what an OS will be used for. So allowing such things to be 
changed without having to reboot the machine is in my mind quite a 
powerful feature we should keep taking adavntage of.

Regards,
Nadia
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