Gentoo Archives: gentoo-amd64

From: Josh Sled <jsled@××××××××××××.org>
To: gentoo-amd64@l.g.o
Subject: Re: [gentoo-amd64] New install - basic question
Date: Sat, 05 Feb 2011 17:05:50
Message-Id: 8739o2zbwg.fsf@phoenix.asynchronous.org
In Reply to: [gentoo-amd64] New install - basic question by Paul Stear
1 Paul Stear <gentoo@××××××××××××.com> writes:
2 > I am currently using amd64 2 core processor but now have the chance to use
3 > an intel quad 64 processor.
4 > This might be a silly question but is it best to do a compltly new
5 > install?
6 […]
7 > Which chost and cflags should I use?
8
9 I just did this transition a couple of weeks ago … Athlon 64 X2 to
10 i7-950. You don't need to do a full reinstall.
11
12 I found http://forums.gentoo.org/viewtopic-t-715522-start-150.html?sid=da3871db3f6144b9f9c4c9dabe34c6d4
13 interesting reading leading up to the change, especially ezakimak2's
14 post of 2010-04-12 15:00.
15
16 I did the same procedure as he outlines:
17
18 - edit /etc/make.conf to change CFLAGS from -march=k8 to -march=generic
19 - `emerge system`
20 - rebuilt kernel for generic i686, new mobo
21 - shut down, swap hardware, start up
22 - edit /etc/make.conf to change CFLAGS to -march=native
23 - `emerge system`
24
25 The biggest problem I had was not building a kernel that included all
26 the drivers appropriate to my new motherboard, leading to kernel panic
27 immediately on startup and many hours spent that day with System Rescue
28 CD. :( Unfortunately, SystemRescueCD seemed to identify my boot drive
29 and raid/lvm setup wrong, which was very distressing and misleading for
30 most of that time. Once I figured that out and re-mounted everything
31 correctly, I was able to chroot into my own system as per
32 http://www.gentoo.org/doc/en/handbook/handbook-amd64.xml?part=1&chap=6#doc_chap1
33 and build and install an appropriate kernel.
34
35
36 I did change some USE flags and rebuilt media packages, but I haven't
37 needed to rebuild anything else, yet. X, Gnome, emacs, Chrome, &c. all
38 ran perfectly fine after things were up and running; I wasn't running
39 any particularly crazy CFLAGS before.
40
41 http://en.gentoo-wiki.com/wiki/Safe_Cflags is always a good reference
42 for CFLAGS, though as they point out, these days it's just
43 "-march=native" and let GCC figure it out.
44
45 CHOST should be unchanged from your current setting:
46 CHOST="x86_64-pc-linux-gnu". If this is not your current setting, then
47 you are not running 64-bit, and you might want to take the opportunity
48 to do a complete reinstall, yes.
49
50 --
51 ...jsled
52 http://asynchronous.org/ - a=jsled; b=asynchronous.org; echo ${a}@${b}