Remove gcc, gcc-c++ and make from minimal build root

[Vít Ondruch]

Dne 13.1.2015 v 16:35 Peter Robinson napsal(a):
>>> You can interpret these data yourself, but with less packages in build root,
>>> I can see:
>>>
>>> 1) Saved build time
>>> 2) Saved network bandwidth
>>> 3) Saved storage
>>> 4) Less things to break
>> Just to make sure I'm reading the data correctly, your tests show a
>> maximum approximate savings of 20 seconds going from the current
>> buildroot to the minimal shell root?
> That's on a local laptop with a SSD so hardly indicative of the
> standard koji build env.

Right, relengs/infrastructure guys are the only one who could give us
numbers for Koji. But we should not focus just on Koji, packagers are
very important asset as well. They provide their own resources to Fedora.

>
>>>   Versus how long will it take to
>>> either modify all these packages / write and run the script to do
>>> that?  Is A > B?
>>>
>>>
>>> There are things which are hard to quantify. If you want to prohibit any
>>> change, this is probably right question to ask. Of course answering such
>>> questions also takes some time, I hope you will count it into the final
>>> equation at the end, although hard to say on which side it should belong.
>> I don't think the original question was all that great.  If we were to
>> script the change to add the BRs, it would take time but it would
>> mostly be a one-time cost.  Reducing buildroot time creation, network
>> bandwidth, and storage savings is a reduction over each new buildroot
>> instance creation over a long period of time.  And as you said, you
>> could also wind up saving time for issues where the buildroot doesn't
>> actually install because of broken packages (e.g. a broken perl dep or
>> something).  The question, as posed, wasn't really taking everything
>> into account.
>>
>> That being said, 20 seconds isn't saving very much.  The network
>> bandwidth savings exists, but given that mock caches packages it isn't
>> a savings for every build.  The storage savings I'm not sure I really
>> agree with because mock roots are transient things and you can delete
>> them if you need to.  You only wind up saving a few megabytes.  I'm
>> not sure this is compelling enough data at the moment.
> And the new mock does have the ability to use a pre created COW build
> root off local disk (I've not looked closely at exact implementation
> deteails) which should actually remove the vast majority of all of the
> above savings and make most of this a mute point. I'm not sure what
> extra work needs to be done to make that standard in koji though.

Well, I used to be more optimistic about LVM snapshots prior I tried it
myself :/ But it should be definitely more useful for Koji then for my
local builds. I highly suggest everybody to at least try the LVM plugin.

Vít