Loading from squashfs with zstd compression slower than ext4

[Jonathan Liu]

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)

Regards,
Jonathan