Bug#694282: openssh: uses too much system ressources to build

[Thorsten Glaser <tg@mirbsd.de>]

Source: openssh
Version: 6.0p1-3
Severity: important

Hi!

While building src:openssh, I noticed unusually high CPU load and
 1517 pts/1    S+     0:00 /usr/bin/make -C build-deb -j 2 ASKPASS_PROGRAM=/usr/bin/ssh-askpass
and later, in the build logs as they scrolled past:
[…]
make[2]: Leaving directory `/tmp/buildd/openssh-6.0p1/build-deb'
/usr/bin/make -C build-udeb -j 2 ASKPASS_PROGRAM='/usr/bin/ssh-askpass' ssh scp sftp sshd ssh-keygen
make[2]: Entering directory `/tmp/buildd/openssh-6.0p1/build-udeb'
[…]

And this despite me *not* having the “parallel” keyword set
in DEB_BUILD_OPTIONS.

I consider this a Policy violation, but as it only affects
buildds, have refrained from considering it release critical,
though this is only as we’re in deep freeze.

My rationale behind this reading of Policy is thus:

(a) I might be on a ressource-constrained machine, or one
    where running multiple threads is unstable (I think
    some of the mips64 machines fall into that category,
    and kfreebsd-* long used to). Building with two threads
    may use more than twice the CPU and RAM than linear
    building. (In my experience, the positive effects of
    disc I/O related things and .text sharing are rather
    neglegible, especially during package builds which
    tend to cluster related tasks.)

(b) Even on an 8-core 64GiB-RAM monster, if I do not specify
    parallel or parallel=\d in DEB_BUILD_OPTIONS, a package
    has absolutely no business using more than one thread of
    execution at a given time because I might want to use the
    machine otherwise and/or run multiple builds in parallel,
    scheduling CPU and RAM usage myself.

Please refrain from adding the -j option to gmake from your
next upload onwards unless parallel is given (Policy §4.9.1).

Thanks!

-- System Information:
Debian Release: wheezy/sid
  APT prefers unreleased
  APT policy: (500, 'unreleased'), (500, 'unstable')
Architecture: m68k

Kernel: Linux 3.2.0-4-atari
Locale: LANG=C, LC_CTYPE=en_GB.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/mksh-static