Bug#943913: lintian: processing packages with many manpages is very slow

[Sven Joachim <svenjoac@gmx.de>]

Bringing man-db and libseccomp maintainers into the loop.

On 2019-10-31 23:01 -0700, Felix Lechner wrote:

> On Thu, Oct 31, 2019 at 11:33 AM Sven Joachim <svenjoac@gmx.de> wrote:
>>
>> Running lintian on packages with many manpages is painfully slow.
>
> I can confirm that it takes a long time:
>
> $ time frontend/lintian ../manpages-dev_5.03-1_all.deb
> I: manpages-dev:
> cannot-check-whether-usr-share-doc-symlink-points-to-foreign-package
> I: manpages-dev: spelling-error-in-manpage
> usr/share/man/man3/fgetws.3.gz "permit to" "permit one to"
> I: manpages-dev: spelling-error-in-manpage
> usr/share/man/man3/gethostbyname.3.gz "permits to" "permits one to"
> I: manpages-dev: spelling-error-in-manpage
> usr/share/man/man3/inet_net_pton.3.gz pres press
> I: manpages-dev: spelling-error-in-manpage ... use
> --no-tag-display-limit to see all (or pipe to a file/program)
> W: manpages-dev: manpage-has-errors-from-man
> usr/share/man/man2/ioctl_list.2.gz 730: warning [p 8, 2.7i]: cannot
> adjust line
> W: manpages-dev: manpage-has-errors-from-man
> usr/share/man/man2/syscall.2.gz 200: warning [p 2, 5.5i]: cannot
> adjust line
> N: 3 tags overridden (3 info)
>
> real    0m50.609s
> user    3m38.614s
> sys    0m16.174s
>
> In a first attempt to get to the issue, I reverted commit 067ec6cb but
> it took about the same:
>
> real    0m51.193s
> user    3m39.174s
> sys    0m15.833s
>
> Do you have older measurements to which we can compare this performance?

In a buster chroot lintian (version 2.15.0) is about seven times faster
on the same manpages-dev package, however in sid downgrading lintian or
man-db to their buster versions did not help.

To track down the problem, I upgraded packages piecemeal from buster to
sid in a chroot, and the massive lintian slowdown happened after
upgrading libseccomp2 from 2.3.3-4 to 2.4.1-2.  Hopefully the man-db and
libseccomp maintainers can help here.

Cheers,
       Sven