On Tue, Jul 12, 2016 at 08:10:49PM +0100, Dr. David Alan Gilbert wrote: > * 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)
Glad that it is not just me! ;-) Thanx, Paul