multiple DISTRO's in tmp

multiple DISTRO's in tmp

[Frans Meulenbroeks]

I bumped upon the following issue.

Normally I use angstrom as distro, but this time I needed a small
image to be used in an initramfs.
In order to achieve that I changed DISTRO in my local.conf to minimal
(tried minimal-uclibc first, but that would complain before generating
packages, probably due to a mismatch between my target (powerpc) and
uclibc (I refrained from sidetracking to dig into it)).

However, when trying to build minimal, it immediately complained about
DISTRO_PR (minimal does not have DISTRO_PR, which you may find a bug,
but anyway that is what exists now).
I had to put it in a new tmp dir.

However, I was wondering: wouldn't it be nice to allow multiple
distro's in one tmp dir (so that e.g. if they share the same version
of a recipe (like m4-native or os), this does not need to be
recompiled?

If this is considered to be a good plan what would be the best way to
achieve this?

Frans

Re: multiple DISTRO's in tmp

[Phil Blundell]

On Fri, 2009-12-11 at 09:39 +0100, Frans Meulenbroeks wrote:
> However, I was wondering: wouldn't it be nice to allow multiple
> distro's in one tmp dir (so that e.g. if they share the same version
> of a recipe (like m4-native or os), this does not need to be
> recompiled?

Even if the (PN, PV) tuple is the same for two DISTROs it doesn't
necessarily follow that the resulting packages will be the same.  They
might have selected different compilers, configuration options, or
versions of depended-on packages.  Or they might have a different
filesystem layout, or any number of other things.

So, practically speaking, no: it isn't going to be feasible to make
multiple DISTROs coexist in a single TMPDIR.  This is a case where you
do need to create a separate TMPDIR.

p.

Re: multiple DISTRO's in tmp

[Frans Meulenbroeks]

2009/12/11 Phil Blundell <philb@gnu.org>:
> On Fri, 2009-12-11 at 09:39 +0100, Frans Meulenbroeks wrote:
>> However, I was wondering: wouldn't it be nice to allow multiple
>> distro's in one tmp dir (so that e.g. if they share the same version
>> of a recipe (like m4-native or os), this does not need to be
>> recompiled?
>
> Even if the (PN, PV) tuple is the same for two DISTROs it doesn't
> necessarily follow that the resulting packages will be the same.  They
> might have selected different compilers, configuration options, or
> versions of depended-on packages.  Or they might have a different
> filesystem layout, or any number of other things.
>
> So, practically speaking, no: it isn't going to be feasible to make
> multiple DISTROs coexist in a single TMPDIR.  This is a case where you
> do need to create a separate TMPDIR.

I understand that. Then again it *is* possible for multiple machines
in the same distro to co-exist, even though the machine config file
could change some flags.

Rethinking it, I would expect that if things can be shared it would be
in the native area (and perhaps some things in cross).

Actually just bumped into this because my tmp dir for angstrom was
about 18 GB and ofc I didn't have sufficient free space for another
tree (and also not really enough patience to wait out a build of the
cross tools).

Since my main goal was a small filesystem for initramfs, maybe it
would be better to make a recipe for a small package (e.g.
minimal_console_image.bb)

Frans

Re: multiple DISTRO's in tmp

[Richard Purdie]

On Fri, 2009-12-11 at 11:29 +0100, Frans Meulenbroeks wrote:
> 2009/12/11 Phil Blundell <philb@gnu.org>:
> > On Fri, 2009-12-11 at 09:39 +0100, Frans Meulenbroeks wrote:
> >> However, I was wondering: wouldn't it be nice to allow multiple
> >> distro's in one tmp dir (so that e.g. if they share the same version
> >> of a recipe (like m4-native or os), this does not need to be
> >> recompiled?
> >
> > Even if the (PN, PV) tuple is the same for two DISTROs it doesn't
> > necessarily follow that the resulting packages will be the same.  They
> > might have selected different compilers, configuration options, or
> > versions of depended-on packages.  Or they might have a different
> > filesystem layout, or any number of other things.
> >
> > So, practically speaking, no: it isn't going to be feasible to make
> > multiple DISTROs coexist in a single TMPDIR.  This is a case where you
> > do need to create a separate TMPDIR.
> 
> I understand that. Then again it *is* possible for multiple machines
> in the same distro to co-exist, even though the machine config file
> could change some flags.
> 
> Rethinking it, I would expect that if things can be shared it would be
> in the native area (and perhaps some things in cross).
> 
> Actually just bumped into this because my tmp dir for angstrom was
> about 18 GB and ofc I didn't have sufficient free space for another
> tree (and also not really enough patience to wait out a build of the
> cross tools).
> 
> Since my main goal was a small filesystem for initramfs, maybe it
> would be better to make a recipe for a small package (e.g.
> minimal_console_image.bb)

Phil is right, its not intended to be able to share multiple DISTROs in
the same TMPDIR and it never will be. Yes, in some cases its possible
things might match but knowing when they do and when they don't is
difficult to tell.

You need separate tmp directories I'm afraid.

Cheers,

Richard

Re: multiple DISTRO's in tmp

[Khem Raj]

On Fri, Dec 11, 2009 at 2:29 AM, Frans Meulenbroeks
<fransmeulenbroeks@gmail.com> wrote:
> 2009/12/11 Phil Blundell <philb@gnu.org>:
>> On Fri, 2009-12-11 at 09:39 +0100, Frans Meulenbroeks wrote:
>>> However, I was wondering: wouldn't it be nice to allow multiple
>>> distro's in one tmp dir (so that e.g. if they share the same version
>>> of a recipe (like m4-native or os), this does not need to be
>>> recompiled?
>>
>> Even if the (PN, PV) tuple is the same for two DISTROs it doesn't
>> necessarily follow that the resulting packages will be the same.  They
>> might have selected different compilers, configuration options, or
>> versions of depended-on packages.  Or they might have a different
>> filesystem layout, or any number of other things.
>>
>> So, practically speaking, no: it isn't going to be feasible to make
>> multiple DISTROs coexist in a single TMPDIR.  This is a case where you
>> do need to create a separate TMPDIR.
>
> I understand that. Then again it *is* possible for multiple machines
> in the same distro to co-exist, even though the machine config file
> could change some flags.
>
> Rethinking it, I would expect that if things can be shared it would be
> in the native area (and perhaps some things in cross).
>
> Actually just bumped into this because my tmp dir for angstrom was
> about 18 GB and ofc I didn't have sufficient free space for another
> tree (and also not really enough patience to wait out a build of the
> cross tools).

IIRC angstrom used -ggdb3 (which may not be case anymore) which means
more than half of your total size it consumed
by elaborated debug info for code which is compiled at O2 and most of
the debug info
will not be usable. Change using -g instead to reduce the bloat.

-Khem

Re: multiple DISTRO's in tmp

[Graeme Gregory]

On Fri, Dec 11, 2009 at 09:39:21AM +0100, Frans Meulenbroeks wrote:
> I bumped upon the following issue.
> 
> Normally I use angstrom as distro, but this time I needed a small
> image to be used in an initramfs.
> In order to achieve that I changed DISTRO in my local.conf to minimal
> (tried minimal-uclibc first, but that would complain before generating
> packages, probably due to a mismatch between my target (powerpc) and
> uclibc (I refrained from sidetracking to dig into it)).
> 
minimal being an Angstrom clone will not actually produce smaller
images. I would suggest for an initramfs you just switch Angstrom
to uclibc mode.

The only real advantage micro has in size is that it creates less
directories. The images are not as far as I can see physically any
smaller.

Graeme

Re: multiple DISTRO's in tmp

[Phil Blundell]

On Fri, 2009-12-11 at 08:47 -0700, Graeme Gregory wrote:
> The only real advantage micro has in size is that it creates less
> directories. The images are not as far as I can see physically any
> smaller.

You should generally get smaller images with micro, though how much
smaller will obviously depend on what exactly you are building.  What
file sizes were you seeing in your test?

p.

Re: multiple DISTRO's in tmp

[Koen Kooi]

On 11-12-09 09:39, Frans Meulenbroeks wrote:
> I bumped upon the following issue.
>
> Normally I use angstrom as distro, but this time I needed a small
> image to be used in an initramfs.

My initramfs built with angstrom is 80KiB and it has an fbdev GUI, how 
much smaller do you want to get with changing DISTRO?

regards,

Koen

Re: multiple DISTRO's in tmp

[Frans Meulenbroeks]

2009/12/12 Koen Kooi <k.kooi@student.utwente.nl>:
> On 11-12-09 09:39, Frans Meulenbroeks wrote:
>>
>> I bumped upon the following issue.
>>
>> Normally I use angstrom as distro, but this time I needed a small
>> image to be used in an initramfs.
>
> My initramfs built with angstrom is 80KiB and it has an fbdev GUI, how much
> smaller do you want to get with changing DISTRO?

80 kb is small enough for me.
What do you build to get that?

Frans

Re: multiple DISTRO's in tmp

[Koen Kooi]

On 12-12-09 23:35, Frans Meulenbroeks wrote:
> 2009/12/12 Koen Kooi<k.kooi@student.utwente.nl>:
>> On 11-12-09 09:39, Frans Meulenbroeks wrote:
>>>
>>> I bumped upon the following issue.
>>>
>>> Normally I use angstrom as distro, but this time I needed a small
>>> image to be used in an initramfs.
>>
>> My initramfs built with angstrom is 80KiB and it has an fbdev GUI, how much
>> smaller do you want to get with changing DISTRO?
>
> 80 kb is small enough for me.
> What do you build to get that?


kexecboot for beagleboard.

regards,

Koen