[PATCH] kbuild: Add KDEB_COMPRESS_LEVEL to control compression level

[PATCH] kbuild: Add KDEB_COMPRESS_LEVEL to control compression level

[Matt Fleming]

From: Matt Fleming <mfleming@cloudflare.com>

Give users more control to tradeoff compression time vs compressed size
when building debian packages with a new KDEB_COMPRESS_LEVEL option.

Here are some examples of using KDEB_COMPRESS=xz with
KDEB_COMPRESS_LEVEL=1 through to KDEB_COMPRESS_LEVEL=6 with the
bindeb-pkg target:

  Level Time to compress Compressed size (bytes)
  ----- ---------------- -----------------------
      1        0m36.771s               476909176
      2        0m40.335s               474832644
      3        0m43.635s               473845600
      4        1m13.839s               472260012
      5        1m18.657s               464442676
      6        1m20.658s               464355000

Signed-off-by: Matt Fleming <mfleming@cloudflare.com>
---
 scripts/package/debian/rules | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/scripts/package/debian/rules b/scripts/package/debian/rules
index ca07243bd5cd..616ecf1d4d1b 100755
--- a/scripts/package/debian/rules
+++ b/scripts/package/debian/rules
@@ -52,7 +52,7 @@ define binary
 	$(Q)dh_fixperms $(DH_OPTIONS)
 	$(Q)dh_gencontrol $(DH_OPTIONS) -- -f$(call mk-files,$@)
 	$(Q)dh_md5sums $(DH_OPTIONS)
-	$(Q)dh_builddeb $(DH_OPTIONS) -- $(addprefix -Z,$(KDEB_COMPRESS))
+	$(Q)dh_builddeb $(DH_OPTIONS) -- $(addprefix -Z,$(KDEB_COMPRESS)) $(addprefix -z,$(KDEB_COMPRESS_LEVEL))
 endef
 
 .PHONY: $(binary-targets)
-- 
2.34.1

Re: [PATCH] kbuild: Add KDEB_COMPRESS_LEVEL to control compression level

[Matt Fleming]

On Fri, Mar 7, 2025 at 3:09 PM Matt Fleming <matt@readmodwrite.com> wrote:
>
> From: Matt Fleming <mfleming@cloudflare.com>
>
> Give users more control to tradeoff compression time vs compressed size
> when building debian packages with a new KDEB_COMPRESS_LEVEL option.

Ping? Any feedback on this patch?

Re: [PATCH] kbuild: Add KDEB_COMPRESS_LEVEL to control compression level

[Masahiro Yamada]

On Thu, Mar 13, 2025 at 9:38 PM Matt Fleming <matt@readmodwrite.com> wrote:
>
> On Fri, Mar 7, 2025 at 3:09 PM Matt Fleming <matt@readmodwrite.com> wrote:
> >
> > From: Matt Fleming <mfleming@cloudflare.com>
> >
> > Give users more control to tradeoff compression time vs compressed size
> > when building debian packages with a new KDEB_COMPRESS_LEVEL option.
>
> Ping? Any feedback on this patch?

Sorry, I missed this.
I would have missed this completely without your ping
because this was not sent to linux-kbuild ML.
(sometimes I still notice, but sometimes I do not.
Including linux-kbuild ML increases the probability of my notice)


"man dpkg-deb" describes

       DPKG_DEB_COMPRESSOR_LEVEL
           Sets the compressor level to use (since dpkg 1.21.10).

           The -z option overrides this value.


This provides the same functionality as KDEB_COMPRESS_LEVEL
you are adding.


If you use dpkg>=1.21.10, you can do

 $  DPKG_DEB_COMPRESSOR_LEVEL=1 make bindeb-pkg


KDEB_COMPRESS_LEVEL might be useful for users of old dpkg
versions, but I do not want to add an option which we know is already
duplicated, since we would end up with removing it again sooner or later.


I even want to remove the currently-supported KDEB_COMPRESS
at some point in the future.
So, I submitted a patch as a reminder for myself:
https://lore.kernel.org/linux-kbuild/20250314095337.2209653-1-masahiroy@kernel.org/T/#u





--
Best Regards
Masahiro Yamada

Re: [PATCH] kbuild: Add KDEB_COMPRESS_LEVEL to control compression level

[Matt Fleming]

On Fri, Mar 14, 2025 at 10:07 AM Masahiro Yamada <masahiroy@kernel.org> wrote:
>
> Sorry, I missed this.
> I would have missed this completely without your ping
> because this was not sent to linux-kbuild ML.
> (sometimes I still notice, but sometimes I do not.
> Including linux-kbuild ML increases the probability of my notice)

My mistake. I will include linux-kbuild in future.

> If you use dpkg>=1.21.10, you can do
>
>  $  DPKG_DEB_COMPRESSOR_LEVEL=1 make bindeb-pkg
>
>
> KDEB_COMPRESS_LEVEL might be useful for users of old dpkg
> versions, but I do not want to add an option which we know is already
> duplicated, since we would end up with removing it again sooner or later.

OK makes sense.

Thanks,
Matt