Re: Why we are going to have to go DirectIO

On Wed, Dec 4, 2013 at 2:31 PM, Jonathan Corbet <corbet(at)lwn(dot)net> wrote:
> For those interested in the details... (1) It's not quite 50/50, that's one
> bound for how the balance is allowed to go. (2) Anybody trying to add
> tunables to the kernel tends to run into resistance. Exposing thousands of
> knobs tends to lead to a situation where you *have* to be an expert on all
> those knobs to get decent behavior out of your system. So there is a big
> emphasis on having the kernel tune itself whenever possible. Here is a
> situation where that is not always happening, but a fix (which introduces
> no knob) is in the works.

I think there are interesting parallels here with the 'query plan
hints' debate. In both cases I think the conservative voices are
correct: better not to go crazy adding knobs.

merlin