Loading from squashfs with zstd compression slower than ext4

[Jonathan Liu]

Hi Simon,

On Thu, 1 Jun 2023 at 11:27, Jonathan Liu <net147 at gmail.com> wrote:
>
> Hi Simon,
>
> On Thu, 1 Jun 2023 at 03:13, Simon Glass <sjg at chromium.org> wrote:
> >
> > Hi Jonathan,
> >
> > On Wed, 31 May 2023 at 06:52, Jonathan Liu <net147 at gmail.com> wrote:
> > >
> > > Hi All,
> > >
> > > I noticed that loading from squashfs with zstd compression is
> > > significantly slower than ext4 on RK3399 using U-Boot 2022.01. The
> > > filesystem is located on eMMC.
> > >
> > > I have CONFIG_BLOCK_CACHE=y in .config and am using the generic load command.
> > >
> > > ext4:
> > > 15682578 bytes read in 366 ms (40.9 MiB/s)
> > >
> > > SquashFS with zstd compression:
> > > 15685001 bytes read in 2339 ms (6.4 MiB/s)
> > >
> > > Any suggestions on how to speed up loading from SquashFS with zstd compression?
>
> >
> > Could it just be that zstd is slow? Have you tried lz4?
> >

>
> I tried LZ4 but get "Error: unknown compression type."
> It seems the SquashFS decompressor only supports lzo, gzip and zstd -
> https://source.denx.de/u-boot/u-boot/-/blob/master/fs/squashfs/sqfs_decompressor.c
>
> ext4:
> 15682578 bytes read in 366 ms (40.9 MiB/s)
>
> SquashFS with lzo compression (~129 MiB squashfs):
> 15686657 bytes read in 1032 ms (14.5 MiB/s)
>
> SquashFS with gzip compression (~116 MiB squashfs):
> 15686657 bytes read in 1494 ms (10 MiB/s)
>
> SquashFS with zstd compression (~107 MiB squashfs):
> 15685001 bytes read in 2339 ms (6.4 MiB/s)

SquashFS with zstd compression seems to be even slower after zstd was
updated to 1.5.2 in U-Boot.

SquashFS with zstd compression (~107 MiB squashfs), with zstd 1.5.2
update cherry-picked from
https://source.denx.de/u-boot/u-boot/-/commit/4b9b25d943ff95c7421cab261333fc29852fe3b1:
15686657 bytes read in 2726 ms (5.5 MiB/s)

Regards,
Jonathan