Re: [PATCH] drm: Reduce object size of DRM_ERROR and DRM_DEBUG uses

From: Joe Perches
Date: Thu Mar 15 2018 - 12:30:07 EST


On Thu, 2018-03-15 at 18:14 +0200, Ville Syrjälä wrote:
> > There's no trade-off in this patch for faster/larger.
> > This patch is simply smaller. Smaller is better.
>
> This feels a bit like saying pink is better than red because it's
> more pink.

Silly. If you can't say smaller total object code that
performs the same task identically is better, I think
we can't discuss much of anything about code together.

Any printk related mechanism is not fast-path so any
icache dilution isn't an issue.

> That said, I'm not arguing against this patch as such. Making things
> smaller "just because" usually doesn't cause problems.

It seems more like you haven't read the patch.

> But I was
> hoping that we might be after some more tangible gains here, and
> thus pointed out that there may be a better way to achieve even
> bigger gains.

Sure, it's just any such a discussion should not affect
this patch being applied.

This patch reduces the argument count of the drm_printk
(now drm_dbg) call and so is faster to execute even if
the emit test is internal to the drm_dbg function.