On 04/02/16 12:01, Christopher Samuel wrote: > Does anyone know how the Intel compilers detect architecture? Do they > look at the model/stepping info or do they do some other tricks?
Sorry - I was being rushed to go for lunch with others when writing that, what I meant was do they parse /proc/cpuinfo or do they use the cpuid instruction and (as I would have expected) they don't refer to /proc/cpuinfo. Experimenting with hwloc shows that the cpuid instructions reflect what is in /proc/cpuinfo (not surprising as those should just reflect the values they return). I've now got access to two hosts, both declare themselves the same family (Sandybridge, model 42) but one of which has a hack that exposes the avx2 flag. Compiling a hello world on a physical Haswell system with the Intel compilers and -xHOST results in a binary that won't start on the one without the avx2 flag but will on the one that does, despite them both being in the same model. So it appears that side at least depends on the individual flags and not the model (which again makes good sense if you think about future proofing different chip variants). All the best, Chris -- Christopher Samuel Senior Systems Administrator VLSCI - Victorian Life Sciences Computation Initiative Email: [email protected] Phone: +61 (0)3 903 55545 http://www.vlsci.org.au/ http://twitter.com/vlsci _______________________________________________ Beowulf mailing list, [email protected] sponsored by Penguin Computing To change your subscription (digest mode or unsubscribe) visit http://www.beowulf.org/mailman/listinfo/beowulf
