Re: [PATCH] Revert "lib: sparse: Make CHUNK_TYPE_RAW buffer aligned"

Gary Bisson
2022-11-21T14:50:39Z

Hi,

On Fri, Nov 18, 2022 at 10:36:58AM -0500, Sean Anderson wrote:
> On 11/18/22 07:13, Gary Bisson wrote:
> > This reverts commit 62649165cb02ab95b57360bb362886935f524f26.
> >
> > The patch decreased the write performance quite a bit.
> > Here is an example on an i.MX 8M Quad platform.
> > - Before the revert:
> > Sending sparse 'vendor' 1/2 (516436 KB) OKAY [ 5.113s]
> > Writing 'vendor' OKAY [128.335s]
> > Sending sparse 'vendor' 2/2 (76100 KB) OKAY [ 0.802s]
> > Writing 'vendor' OKAY [ 27.902s]
> > - After the revert:
> > Sending sparse 'vendor' 1/2 (516436 KB) OKAY [ 5.310s]
> > Writing 'vendor' OKAY [ 18.041s]
> > Sending sparse 'vendor' 2/2 (76100 KB) OKAY [ 1.244s]
> > Writing 'vendor' OKAY [ 2.663s]
> >
> > Considering that the patch only moves buffer around to avoid a warning
> > message about misaligned buffers, let's keep the best performances.
>
> So what is the point of this warning?

Well the warning does say something true that the cache operation is not
aligned. Better ask Simon as he's the one who changed the print from a
debug to warn_non_spl one:
bcc53bf0958 arm: Show cache warnings in U-Boot proper only

BTW, in my case I couldn't see the misaligned messages, yet I saw the
performance hit described above.

Regards,
Gary