linux-kernel - Re: [PATCH] kbuild: use smaller dictionary size for zstd module compression

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Date:   Fri, 17 Sep 2021 17:07:06 +0200
From:   Piotr Górski <lucjan.lucjanov@...il.com>
To:     Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Cc:     Linux Kbuild mailing list <linux-kbuild@...r.kernel.org>,
        Michal Marek <michal.lkml@...kovi.net>,
        Masahiro Yamada <masahiroy@...nel.org>,
        Nick Desaulniers <ndesaulniers@...gle.com>
Subject: Re: [PATCH] kbuild: use smaller dictionary size for zstd module compression

Ping...

pt., 10 wrz 2021 o 15:10 Piotr Gorski <lucjan.lucjanov@...il.com> napisał(a):
>
> By default, zstd without parameters uses a dictionary size of 8 MB.
> However, most modules are much smaller than that.
> Use a dictionary size of 2 MB for module compression, resulting in
> slightly higher compression speed while still maintaining a good
> compression ratio.
> The --zstd=wlog=21 option is equivalent to --lzma2=dict=2MiB used in XZ compression.
>
> Signed-off-by: Piotr Gorski <lucjan.lucjanov@...il.com>
> ---
>  scripts/Makefile.modinst | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/scripts/Makefile.modinst b/scripts/Makefile.modinst
> index ff9b09e4cfca..c3475e5aca7c 100644
> --- a/scripts/Makefile.modinst
> +++ b/scripts/Makefile.modinst
> @@ -97,7 +97,7 @@ quiet_cmd_gzip = GZIP    $@
>  quiet_cmd_xz = XZ      $@
>        cmd_xz = $(XZ) --lzma2=dict=2MiB -f $<
>  quiet_cmd_zstd = ZSTD    $@
> -      cmd_zstd = $(ZSTD) -T0 --rm -f -q $<
> +      cmd_zstd = $(ZSTD) --zstd=wlog=21 -T0 --rm -f -q $<
>
>  $(dst)/%.ko.gz: $(dst)/%.ko FORCE
>         $(call cmd,gzip)
> --
> 2.33.0.142.ge0a2f5cbc5
>