On Fri, Aug 17, 2012 at 2:53 PM, Florian Philipp <li...@binarywings.net> wrote: > Am 17.08.2012 10:58, schrieb Jorge Almeida: >> >> 1) Is this strategy right? If so, any other flags to add? (or any >> flags to remove from the list?) >> >> 2) The --param flags are the ones of the computer that will do the >> compiling. I'm guessing the produced binaries are compatible with cpu >> with different --param flags. Is this right? >> >> TIA >> >> Jorge Almeida >> > > 1) Yes. But as you can see, -march=prescott is basically a subset of > atom. In fact, before there was a -march=atom option, prescott was the > best flag for atoms. I think you can avoid some hassle by simply > enabling "-march=prescott --param l1-cache-line-size=64 --param > l2-cache-size=512". > > 2) Yes, the param flags do not affect compatibility. Using the lower > value will probably be better but this is just an educated guess. >
What about: CFLAGS="-O2 -pipe -fomit-frame-pointer -march=prescott -mtune=atom --param l1-cache-size=16 --param l1-cache-line-size=64 --param l2-cache-size=1024" If prescott were exactly a subset of atom, this would yield the best of both worlds. Can it still be safe? I read in http://forums.gentoo.org/viewtopic-t-895104.html : atom Intel Atom CPU with 64-bit extensions, MMX, SSE, SSE2, SSE3 and SSSE3 instruction set support. Does this mean that these flags are pulled by -mtune=atom, or do we need to ask for them explicitly? The WiKi shows how to find which flags are pulled by -march=native, but not the other cases. Thanks Jorge Almeida
