[OE-core] wic creates ext4 images that read really slow in u-boot

[Leon Woestenberg]

Hello Mike, all,

On Wed, Feb 20, 2019 at 11:42 AM Mike Looijmans <mike.looijmans at topic.nl> wrote:
>
> On 19-02-19 21:45, Leon Woestenberg wrote:
> > Hello all,
> >
> > On Tue, Feb 19, 2019 at 8:28 PM Andre McCurdy <armccurdy at gmail.com> wrote:
> >> On Tue, Feb 19, 2019 at 9:13 AM Leon Woestenberg <leon at sidebranch.com> wrote:
> >>>
> >>> Hello Mike,
> >>>
> >>> sounds familiar.
> >>>
> >>> On Tue, 19 Feb 2019 at 17:55, Mike Looijmans <mike.looijmans at topic.nl> wrote:
> >>>>
> >>>> Took me a while to figure out why my board took 90 seconds to boot suddenly.
> >>>> The issue turned out to be the ext4 partition created by wic.
> >>>
> >>> I suspect it's not WIC's fault.
> >>>>
> >>> I am aware of two fixes for U-Boot. I will look them up, and reply again to this thread.
> >
> > Google for these two commits. I cherry-picked the first one for my
> > project and can confirm it brings back the desired performance. (Still
> > assuming this is the identical cause as for TO/Mike.)
> >
> > commit 855b8e4f9f255415a7753819e392e4b5d984f35c
> > Author: Matt Madison <matt at madison.systems>
> > Date:   Sat Aug 19 08:46:46 2017 -0700
> >
> >      ext4: cache extent blocks during file reads
> >
> >      A simpler and less-efficient approach to solving
> >      the problem with extent index blocks than what
> >      was in fc0fc50f38a4d7d0554558076a79dfe8b0d78cd5,
> >      but one that does not break write operations.
> >
> >      Signed-off-by: Matt Madison <matt at madison.systems>
>
> I'll give it a try...
>
> You mentioned "two" commits?

Yes the commit above, and *another* approach referred to and mentioned
in the commit message (also with hash).

The block cache feature may solve the problem in a more generic way
(also caching things like directory lookups), whereas the ext4 extent
patches are more specific to ext4 only.

I found the ext4 fixes starting from here:
https://github.com/madisongh/meta-tegra/issues/42

Regards,

Leon.