On Tue, Jul 12, 2016 at 04:55:51PM +0200, Peter Zijlstra wrote: > On Sun, Jul 10, 2016 at 07:43:27AM -0700, Paul E. McKenney wrote: > > On Sun, Jul 10, 2016 at 07:17:19AM +0200, Peter Zijlstra wrote: > > > > > > > > > On 10 July 2016 06:26:39 CEST, "Paul E. McKenney" > > > <paul...@linux.vnet.ibm.com> wrote: > > > >Hello! > > > > > > > >So I ran a quick benchmark which showed stair-step results. I > > > >immediately > > > >thought "Ah, this is due to CPU 0 and 1, 2 and 3, 4 and 5, and 6 and 7 > > > >being threads in a core." Then I thought "Wait, this is an x86!" > > > >Then I dumped out cpu*/topology/thread_siblings_list, getting the > > > >following: > > > > > > > > cpu0/topology/thread_siblings_list: 0-1 > > > > cpu1/topology/thread_siblings_list: 0-1 > > > > cpu2/topology/thread_siblings_list: 2-3 > > > > cpu3/topology/thread_siblings_list: 2-3 > > > > cpu4/topology/thread_siblings_list: 4-5 > > > > cpu5/topology/thread_siblings_list: 4-5 > > > > cpu6/topology/thread_siblings_list: 6-7 > > > > cpu7/topology/thread_siblings_list: 6-7 > > > > > > > > > I'm guessing this is an AMD bulldozer like machine? > > > > /proc/cpuinfo thinks otherwise: > > > > processor : 0 > > vendor_id : GenuineIntel > > cpu family : 6 > > model : 60 > > model name : Intel(R) Core(TM) i7-4710MQ CPU @ 2.50GHz > > Weird, I've never seen an Intel box do that before... hpa, any idea? or > is this just one weird BIOS.
;-) It is a Lenovo W541 laptop, for whatever that might be worth. Roughly on year old. Thanx, Paul