Received-SPF: pass (google.com: domain of linux-kernel+bounces-23803-linux.lists.archive=gmail.com@vger.kernel.org designates 2604:1380:4601:e00::3 as permitted sender) client-ip=2604:1380:4601:e00::3;
Date: Thu, 11 Jan 2024 16:37:28 +0100
From: Nicolas Schier <nicolas@fjasle.eu>
To: Mirsad Todorovac <mirsad.todorovac@alu.hr>
Cc: linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PROBLEM] Very long .deb package build times for bindeb-pkg
 build target
Message-ID: <ZaALOOhEdBP70lDH@bergen.fjasle.eu>
References: <c2adb439-0dea-4de1-996e-5a0caa5c729d@alu.unizg.hr>
Precedence: bulk
MIME-Version: 1.0
Content-Type: multipart/signed; micalg=pgp-sha256;
	protocol="application/pgp-signature"; boundary="RWLzT3EZlFqQQ5iv"
Content-Disposition: inline
In-Reply-To: <c2adb439-0dea-4de1-996e-5a0caa5c729d@alu.unizg.hr>


--RWLzT3EZlFqQQ5iv
Content-Type: text/plain; charset=iso-8859-1
Content-Disposition: inline
Content-Transfer-Encoding: quoted-printable

Hi Mirsad,

On Thu 11 Jan 2024 13:22:39 GMT, Mirsad Todorovac wrote:
> Hi,
>=20
> With this new release, it seems that Debian kernel build uses "xz" in sin=
gle-
> threaded mode:
>=20
> Tasks: 484 total,   2 running, 481 sleeping,   0 stopped,   1 zombie
> %Cpu(s):  2.5 us,  2.2 sy,  6.3 ni, 85.1 id,  2.3 wa,  0.0 hi,  1.7 si,  =
0.0 st
> MiB Mem :  64128.3 total,    524.3 free,   5832.0 used,  58540.9 buff/cac=
he
> MiB Swap:  32760.0 total,  32758.7 free,      1.2 used.  58296.3 avail Mem
>=20
>     PID USER      PR  NI    VIRT    RES    SHR S  %CPU  %MEM     TIME+
> COMMAND
>=20
>  978084 marvin    30  10  112440  97792   2432 R 100.0   0.1  29:30.23 xz
>=20
>=20
> Before dpkg-deb was using up to 3200% of CPU time on a 16 core SMT CPU.
>=20
> Can it be something with dpkg-deb --thread-max=3D%n option?

I cannot find any --thread-max option in Linux tree.  Do you call=20
dpkg-deb manually or somehow induce a thread maximum?

> Waiting for half an hour just for the build of linux-image-...-dbg package
> seems like an overkill ...

With current v6.7 release tree I do not see the reported slow-downs=20
when building bindeb-pkg; I tested by cross-compiling for arm64 on=20
amd64 with CONFIG_MODULE_COMPRESS_XZ=3Dy and =3Dn).

Both take roughly 5mins on my 24-core i9 system.

Kind regards,
Nicolas

--RWLzT3EZlFqQQ5iv
Content-Type: application/pgp-signature; name="signature.asc"

-----BEGIN PGP SIGNATURE-----
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=xQuv
-----END PGP SIGNATURE-----

--RWLzT3EZlFqQQ5iv--