Re: [PATCH v2 0/8] scheduler tinification

From: Ingo Molnar
Date: Tue Jun 13 2017 - 03:12:42 EST



* Nicolas Pitre <nicolas.pitre@xxxxxxxxxx> wrote:

> > A series that shrinks the .text size of the allnoconfig core Linux kernel from 1MB
> > to 9.9MB in isolation is not proof.
>
> I assume you meant 0.9MB.

0.992 MB actually if we apply the ~8k .text savings. 0.9MB would imply 100k of
savings on an allnoconfig kernel.

> It is no proof of course. But I'm following the well known and proven
> "release early, release often" mantra here... unless this is no longer
> promoted?

I'm following that same pattern: I gave you negative review feedback as early as
possible. Fragmention of the scheduler ABI increases complexity and has knock-on
costs - and the kernel size reduction for the usecase you cited are still 1-2
orders of magnitude away from making a practical difference.

> > There will literally have to be two orders of magnitude more patches than that
> > to reach the 32K size envelope, if I (very) optimistically assume that the
> > difficulty to shrink code is constant (which it most certainly is not).
>
> Once again, my goal is _not_ 32KB.
>
> And I don't intend to shrink code. Most of the time I just want to
> _remove_ code. Compiling it out to be precise. The goal of this series
> is all about compiling out code. And to achieve that with the scheduler,
> I simply moved some code to different source files and not including
> those source files in the final build. That keeps the number of #ifdef's
> to a minimum but it makes a big diffstat due to the code movement.

So I'm fine with most of the code movement - let's try this series without any of
the more controversial bits which should make future arguments easier.

Thanks,

Ingo