It's just a coincidence. Most modern machines (many of them are NUMA) have non sequential numbers (to maximize memory bandwidth in the dumb cases).
Brice Le 01/08/2011 15:29, Gabriele Fatigati a écrit : > Ok, > > now it's more clear. Just a little question. Why in a NUMA machine, > PU# are sequential (page 17), and in a non NUMA machine are not > sequential? ( page 16) > > 2011/8/1 Brice Goglin <brice.gog...@inria.fr > <mailto:brice.gog...@inria.fr>> > > You're confusing object types with index types. > > PU is an object type, like Core, Socket, ... "logical processor" > is a generic name for cores when there's no SMT, hardware threads > when there's SMT/Hyperthreading, ... PU is basically the smallest > thing that can run a software thread. > > "P#" is just the way you're numbering object, it works for PU and > for other object types. > > Any object of any type can be identified through a unique logical > index, and possibly non-unique physical index. > > We don't often use the name "logical processor" because it's > indeed confusing. "Processing Unit" is less confusing, that's why > it's the official name for the smallest objects in hwloc. > > Brice > > > > > > > > Le 01/08/2011 15:04, Gabriele Fatigati a écrit : >> Hi Brice, >> >> you said: >> >> "PU P#0" means "PU object with physical index 0". >> "P#" prefix means "physical index". >> >> But from the hwloc manual, page 58: >> >> >> HWLOC_OBJ_PU: Processing Unit, or (Logical) Processor.. >> >> >> but it is in conflict with what you said :( >> >> >> 2011/8/1 Brice Goglin <brice.gog...@inria.fr >> <mailto:brice.gog...@inria.fr>> >> >> "PU P#0" means "PU object with physical index 0". >> "P#" prefix means "physical index". >> "L#" prefix means "logical index" (the one you want to use in >> get_obj_by_type). >> Use -l or -p to switch from one to the other in lstopo. >> >> Brice >> >> >> >> Le 01/08/2011 14:47, Gabriele Fatigati a écrit : >>> Hi Brice, >>> >>> so, if I inderstand well, PU P# numbers are not the same >>> specified as HWLOC_OBJ_PU flag? >>> >>> 2011/8/1 Brice Goglin <brice.gog...@inria.fr >>> <mailto:brice.gog...@inria.fr>> >>> >>> Le 01/08/2011 12:16, Gabriele Fatigati a écrit : >>> > Hi, >>> > >>> > reading a hwloc-v1.2-a4 manual, on page 15, i look an >>> example >>> > with 4-socket 2-core machine with hyperthreading. >>> > >>> > Core id's are not exclusive as said before. PU's id >>> are exclusive but >>> > not physically sequential (I suppose) >>> > >>> > PU P#0 is in socket P#0 on Core P#0. PU P#1 is in >>> another socket! >>> >>> These indexes are "physical indexes" (that's the default >>> in the >>> graphical lstopo output). But we may want to make that >>> clearer in the doc. >>> >>> Brice >>> >>> >>> >>> >>> -- >>> Ing. Gabriele Fatigati >>> >>> Parallel programmer >>> >>> CINECA Systems & Tecnologies Department >>> >>> Supercomputing Group >>> >>> Via Magnanelli 6/3, Casalecchio di Reno (BO) Italy >>> >>> www.cineca.it <http://www.cineca.it> >>> Tel: +39 051 6171722 >>> >>> g.fatigati [AT] cineca.it <http://cineca.it> >> >> >> >> >> -- >> Ing. Gabriele Fatigati >> >> Parallel programmer >> >> CINECA Systems & Tecnologies Department >> >> Supercomputing Group >> >> Via Magnanelli 6/3, Casalecchio di Reno (BO) Italy >> >> www.cineca.it <http://www.cineca.it> Tel: >> +39 051 6171722 >> >> g.fatigati [AT] cineca.it <http://cineca.it> > > > > > -- > Ing. Gabriele Fatigati > > Parallel programmer > > CINECA Systems & Tecnologies Department > > Supercomputing Group > > Via Magnanelli 6/3, Casalecchio di Reno (BO) Italy > > www.cineca.it <http://www.cineca.it> Tel: +39 051 > 6171722 > > g.fatigati [AT] cineca.it <http://cineca.it>
