Gentoo Archives: gentoo-user

From: Helmut Jarausch <jarausch@××××××××××××××××.de>
To: gentoo-user@l.g.o
Subject: Re: [gentoo-user] How to determine 'Least Common Denominator' between Xen(Server) Hosts
Date: Wed, 14 Aug 2013 06:10:39
Message-Id: 1376460630.28792.0@numa-i.igpm.rwth-aachen.de
In Reply to: [gentoo-user] How to determine 'Least Common Denominator' between Xen(Server) Hosts by Pandu Poluan
1 On 08/14/2013 07:18:41 AM, Pandu Poluan wrote:
2 > Hello list!
3 >
4 > My company has 2 HP DL585 G5 servers and 5 Dell R... something
5 > servers. All
6 > using AMD processors. They currently are acting as XenServer hosts.
7 >
8 > How do I determine the 'least common denominator' for Gentoo VMs
9 > (running
10 > as XenServer guests), especially for gcc flags?
11 >
12 > I know that the (theoretical) best performance is to use
13 > -march=native ,
14 > but since the processors of the HP servers are not exactly the same
15 > as the
16 > Dell's, I'm concerned that compiling with -march=native will render
17 > the VMs
18 > unable to migrate between the different hosts.
19 >
20 > Note: Yes I know the HP servers are much older than the Dell ones,
21 > but if I
22 > go -march=native then perform an emerge when the guest is on the Dell
23 > host,
24 > the guest VM might not be able to migrate to the older HPs.
25 >
26 > Rgds,
27 > --
28
29 Why not compute it yourself?
30
31 Do cat /proc/cpuinfo on all machines and compute the intersection of
32 all "flags"
33 Then enter something like the following into /etc/portage/make.conf
34
35 CFLAGS="-O3 -pipe -msse -msse2 -msse3 -msse4a -m3dnow"
36
37 Helmut

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Re: [gentoo-user] How to determine 'Least Common Denominator' between Xen(Server) Hosts Wang Xuerui <idontknw.wang@×××××.com>