* Peter Zijlstra (pet...@infradead.org) wrote: > On Tue, Jul 12, 2016 at 10:49:58AM -0700, H. Peter Anvin wrote: > > On 07/12/16 08:05, Paul E. McKenney wrote: > > The CPU in question (and /proc/cpuinfo should show this) has four cores > > with a total of eight threads. The "siblings" and "cpu cores" fields in > > /proc/cpuinfo should show the same thing. So I am utterly confused > > about what is unexpected here? > > Typically threads are enumerated differently on Intel parts. Namely: > > cpu_id = code_id + nr_cores * smt_id > > which gives, for a 4 core, 2 thread part: > > 0-3: core 0-3, smt0 > 4-7: core 0-3, smt1 > > My Core i7-2600k for example has: > > $ cat /sys/devices/system/cpu/cpu*/topology/thread_siblings_list > 0,4 > 1,5 > 2,6 > 3,7 > 0,4 > 1,5 > 2,6 > 3,7 > > The ordering Paul has, namely 0,1 for core0,smt{0,1} is not something > I've ever seen on an Intel part. AMD otoh does enumerate their CMT stuff > like what Paul has.
Paul's isn't unique: cat /sys/devices/system/cpu/cpu*/topology/thread_siblings_list 0-1 0-1 2-3 2-3 i7-3520M CPU @ 2.90GHz (Dual core with hyperthread, Thinkpad t530, fedora 24) Dave -- -----Open up your eyes, open up your mind, open up your code ------- / Dr. David Alan Gilbert | Running GNU/Linux | Happy \ \ dave @ treblig.org | | In Hex / \ _________________________|_____ http://www.treblig.org |_______/