Gentoo Archives: gentoo-user

From: Peter Wilmott <p@×××××.info>
To: gentoo-user@l.g.o
Subject: Re: [gentoo-user] Serious problem with linode vm
Date: Mon, 15 Apr 2013 16:09:05
Message-Id: 516C2630.8070209@p8952.info
In Reply to: Re: [gentoo-user] Serious problem with linode vm by Tanstaafl
1 On 15/04/13 16:53, Tanstaafl wrote:
2 > On 2013-04-15 11:42 AM, Michael Mol <mikemol@×××××.com> wrote:
3 >> Guessing the new host has different CPU capabilities exposed to the
4 >> guest, either because of a differing hypervisor configuraiton, or
5 >> because of the different underlying hardware.
6 >
7 > Hmmm again...
8 >
9 > CHOST is the same on both:
10 >
11 > CHOST="i686-pc-linux-gnu"
12 >
13 Hi Tanstaafl,
14
15 Basically your issue is that your Gentoo system is compiled to use a
16 specific instruction set, by doing this you get a very small performance
17 increase on that exact CPU model at the cost of incompatibility with
18 other CPUs. In a virtual environment, especially one where you do not
19 control the hardware this is not a great idea since your provider can
20 swap out your CPU with a different model and there isn't much you can do
21 about it.
22
23 If I was you I'd boot off the rescue CD Linode provide, mount your root
24 device, chroot in and set the following values in make.conf for both
25 systems:
26
27 CFLAGS="-O2 -mtune=generic -pipe"
28 CHOST="i686-pc-linux-gnu"
29
30 These settings will build packages that will work on almost every modern
31 CPU out there, once they are set you'll need to re-build @system and
32 @world, hopefully the system will be able to cope with that or you're
33 looking at a full re-build. You also want to be using 32 bit kernels on
34 both systems since they are 32bit systems.
35
36 ---
37 Peter