Re: [gentoo-user] How to determine 'Least Common Denominator' between Xen(Server) Hosts

[Wang Xuerui]

2013/8/14 Helmut Jarausch <jarausch@××××××××××××××××.de>:
> Why not compute it yourself?
>
> Do   cat /proc/cpuinfo on all machines and compute the intersection of all
> "flags"
> Then enter something like the following into /etc/portage/make.conf
>
> CFLAGS="-O3 -pipe -msse -msse2 -msse3 -msse4a -m3dnow"


Or even better, directly intersect the GCC flags which can be obtained
in this way:

echo | gcc -O2 -pipe -march=native -E -v - 2>&1 | grep cc1

Also, according to the Gentoo Handbook going -O3 for the entire system
may cause instability and other problems. Has the situation changed
over the years?