Re: The necessity of running depmod at boot time
On Thu, May 18, 2006 at 07:21:33PM -0300, Margarita Manterola wrote:
> Continuing on the goal of optimizing boot time, quite a number of
> seconds (specially in old machines) can be saved by not running depmod
> at boot time.
>
> Currently it is run by these packages' postinst:
> * [long list]
>
> It looks like it's quite safe to stop running depmod during boot time,
> since both new kernels and new modules run it at install time. If
> there are modules that don't run depmod on installation, they should
> do it.
I think one of the issues here is that it depends on what kernel you
currently use, and iirc there can be a situation where one does not
want to run depmod at installation time, or when that might give wrong
results.
What I think would be best is to have every packages that now requires
running depmod at boot time, will touch a file in
/lib/modules/<kernel-api> when it has changed the kernel (or modules)
significantly so that it is needed to be run, and at boot time only run
depmod if that touched file exists (and have the file removed after
having run depmod succesfully).
This way, depmod at boot is only run after changes in kernel or modules
once for each given kernel API that's booted.
If the package code in each package for this (for the bit to
conditionally run depmod at installation time too) is not trivial, it
might be worth having a bit about this in some dh_* script, so that the
code in question is only written once. I'm not sure here though, I don't
think it's needed as the majority of the code can be in the package
providing depmod.
--Jeroen
--
Jeroen van Wolffelaar
Jeroen@wolffelaar.nl (also for Jabber & MSN; ICQ: 33944357)
http://Jeroen.A-Eskwadraat.nl
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