On Tue, Feb 21, 2017 at 10:19:16PM +0000, Mick wrote > Perhaps I do not understand ... why should the chrooted system need > to use different flags?
See https://gcc.gnu.org/onlinedocs/gcc-4.9.4/gcc/i386-and-x86-64-Options.html#i386-and-x86-64-Options The desktop is "-march=ivybridge" and the netbook is "-march=bonnell". Neither of them can run the other's "-march=native" code. "ivybridge" does not have MOVBE, while "bonnell" does not have SSE4.1, SSE4.2, POPCNT, AVX, AES, PCLMUL, FSGSBASE, RDRND and F16C. gcc will gladly build for whatever Intel cpu you tell it to. I can build "bonnell" code on the "ivybridge". But I can't run it on the "ivybridge" machine. As a compromise, I suppose I could declare the chroot "-march=core2". "core2" is "bonnell" minus MOVBE, so both the netbook and the desktop could run that code, with the netbook getting some, but not all, of the possible optimization. I have a "hot backup" to my desktop, which has a "silvermont" cpu. That's a newer Atom cpu, and it can run "bonnell" code, no problem. But the "ivybridge" machine is not that old, and I prefer to keep my machines until they start dying. -- Walter Dnes <waltd...@waltdnes.org> I don't run "desktop environments"; I run useful applications
