[systemd-devel] lto issues

[Michael Biebl]

Hi,

today I tried compiling systemd v242 (on Debian sid) once using lto
(-Db_lto=true) and once without lto (-Db_lto=false).

The lto build took approximately twice as long on my laptop (using
dpkg-buildpackage, which introduces a bit of overhead):

lto:
real 11m22,605s
user 37m9,675s
sys 2m51,041s

nolto:
real 6m35,615s
user 18m51,782s
sys 2m12,934s

That's kinda expected. What suprised me though is that using lto
produced larger binaries:

File lists identical (after any substitutions)

Control files of package libnss-myhostname: lines which differ (wdiff format)
-----------------------------------------------------------------------------
Installed-Size: [-202-] {+222+}

Control files of package libnss-mymachines: lines which differ (wdiff format)
-----------------------------------------------------------------------------
Depends: libc6 (>= 2.28), {+libcap2 (>= 1:2.10),+} systemd-container (= 242-2)
Installed-Size: [-401-] {+461+}

Control files of package libnss-resolve: lines which differ (wdiff format)
--------------------------------------------------------------------------
Depends: libc6 (>= 2.28), {+libcap2 (>= 1:2.10),+} systemd (= 242-2)
Installed-Size: [-396-] {+460+}

Control files of package libnss-systemd: lines which differ (wdiff format)
--------------------------------------------------------------------------
Depends: libc6 (>= 2.28), {+libcap2 (>= 1:2.10),+} systemd (= 242-2)
Installed-Size: [-400-] {+460+}

Control files of package libpam-systemd: lines which differ (wdiff format)
--------------------------------------------------------------------------
Depends: libc6 (>= 2.28), {+libcap2 (>= 1:2.10),+} libpam0g (>=
0.99.7.1), systemd (= 242-2), libpam-runtime (>= 1.0.1-6), dbus,
systemd-sysv
Installed-Size: [-398-] {+466+}

No differences were encountered between the control files of package
libsystemd-dev

Control files of package libsystemd0: lines which differ (wdiff format)
-----------------------------------------------------------------------
Installed-Size: [-774-] {+862+}
Pre-Depends: libc6 (>= 2.28), {+libcap2 (>= 1:2.10),+} libgcrypt20 (>=
1.8.0), liblz4-1 (>= 0.0~r122), liblzma5 (>= [-5.1.1alpha+20120614)-]
{+5.1.1alpha+20120614), libselinux1 (>= 2.1.9)+}

No differences were encountered between the control files of package libudev-dev

Control files of package libudev1: lines which differ (wdiff format)
--------------------------------------------------------------------
Installed-Size: [-257-] {+297+}

Control files of package systemd: lines which differ (wdiff format)
-------------------------------------------------------------------
Depends: [-libacl1 (>= 2.2.23),-] libapparmor1 (>= 2.9.0-3+exp2),
libaudit1 (>= 1:2.2.1), [-libcap2 (>= 1:2.10),-] libcryptsetup12 (>=
2:1.6.0), libgnutls30 (>= 3.6.6), libgpg-error0 (>= 1.14), libidn2-0
(>= 2.0.0), libip4tc2 (>= 1.8.3), libkmod2 (>= 5~), liblz4-1 (>=
0.0~r130), libmount1 (>= 2.30), libpam0g (>= 0.99.7.1), libpcre2-8-0
(>= 10.32), libseccomp2 (>= 2.3.1), libsystemd0 (= 242-2), util-linux
(>= 2.27.1), mount (>= 2.26), adduser
Installed-Size: [-13781-] {+12696+}
Pre-Depends: {+libacl1 (>= 2.2.23),+} libblkid1 (>= 2.24), libc6 (>=
2.28), {+libcap2 (>= 1:2.10),+} libgcrypt20 (>= 1.8.0), liblz4-1 (>=
0.0~r122), liblzma5 (>= 5.1.1alpha+20120614), libselinux1 (>= 2.1.9)

Control files of package systemd-container: lines which differ (wdiff format)
-----------------------------------------------------------------------------
Installed-Size: [-1118-] {+1126+}

No differences were encountered between the control files of package
systemd-coredump

Control files of package systemd-journal-remote: lines which differ
(wdiff format)
----------------------------------------------------------------------------------
Installed-Size: [-314-] {+318+}

No differences were encountered between the control files of package
systemd-sysv

Control files of package systemd-tests: lines which differ (wdiff format)
-------------------------------------------------------------------------
Depends: libacl1 (>= 2.2.23), libapparmor1 (>= 2.9.0-3+exp2),
libaudit1 (>= 1:2.2.1), libblkid1 (>= 2.24), libc6 (>= 2.28), libcap2
(>= 1:2.10), libcryptsetup12 (>= 2:1.6.0), libdbus-1-3 (>= 1.9.14),
libgcrypt20 (>= 1.8.0), libglib2.0-0 (>= 2.26.0), libgpg-error0 (>=
1.14), [-libidn2-0 (>= 2.0.0), libip4tc2 (>= 1.8.3),-] libkmod2 (>=
5~), liblz4-1 (>= 0.0~r130), libmount1 (>= 2.30), libpam0g (>=
0.99.7.1), libseccomp2 (>= 2.3.1), libselinux1 (>= 2.1.9), libsystemd0
(= 242-2), libudev1 (>= 215), systemd (= 242-2), zlib1g (>= 1:1.1.4),
python3
Installed-Size: [-26530-] {+24446+}

Control files of package udev: lines which differ (wdiff format)
----------------------------------------------------------------
Depends: libacl1 (>= 2.2.23), libblkid1 (>= 2.24), libc6 (>= 2.28),
{+libcap2 (>= 1:2.10), libidn2-0 (>= 0.6),+} libkmod2 (>= 5~),
libselinux1 (>= 2.1.9), adduser, dpkg (>= 1.19.3) | systemd-sysv,
libudev1 (= 242-2), util-linux (>= 2.27.1)
Installed-Size: [-8345-] {+8593+}
-- 
Why is it that all of the instruments seeking intelligent life in the
universe are pointed away from Earth?