Messages in this thread | | | From | "Zhang, Rui" <> | Subject | Re: [patch V3 23/40] x86/cpu: Provide cpu_init/parse_topology() | Date | Sun, 13 Aug 2023 13:30:11 +0000 |
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On Sat, 2023-08-12 at 06:41 +0000, Zhang, Rui wrote: > > + > > +static inline u32 topo_relative_domain_id(u32 apicid, enum > > x86_topology_domains dom) > > +{ > > + if (dom != TOPO_SMT_DOMAIN) > > + apicid >>= x86_topo_system.dom_shifts[dom - 1]; > > + return apicid & (x86_topo_system.dom_size[dom] - 1); > > +} > > relative_domain_id() is used to get a unique id value within its next > higher level. > > > +static void topo_set_ids(struct topo_scan *tscan) > > +{ > > + struct cpuinfo_x86 *c = tscan->c; > > + u32 apicid = c->topo.apicid; > > + > > + c->topo.pkg_id = topo_shift_apicid(apicid, > > TOPO_PKG_DOMAIN); > > + c->topo.die_id = topo_shift_apicid(apicid, > > TOPO_DIE_DOMAIN); > > + > > + /* Relative core ID */ > > + c->topo.core_id = topo_relative_domain_id(apicid, > > TOPO_CORE_DOMAIN); > > My understanding is that, to ensure a package scope unique core_id, > rather than Module/Tile scope unique, what is really needed here is > something like, > apicid >>= x86_topo_system.dom_shifts[SMT]; > c->topo.core_id = apicid & (x86_topo_system.dom_size[PACKAGE] > - 1); > > I don't have chance to confirm this on a platform with Module level > yet, but will do soon. > Tested on an AdlerLake-N platform, which has 2 Ecore Modules only.
[ 0.212526] CPU topo: Max. logical packages: 1 [ 0.212527] CPU topo: Max. logical dies: 1 [ 0.212528] CPU topo: Max. dies per package: 1 [ 0.212531] CPU topo: Max. threads per core: 1 [ 0.212532] CPU topo: Num. cores per package: 8 [ 0.212532] CPU topo: Num. threads per package: 8 [ 0.212532] CPU topo: Allowing 8 present CPUs plus 0 hotplug CPUs [ 0.212535] CPU topo: Thread : 8 [ 0.212537] CPU topo: Core : 8 [ 0.212539] CPU topo: Module : 2 [ 0.212541] CPU topo: Tile : 1 [ 0.212543] CPU topo: Die : 1 [ 0.212545] CPU topo: Package : 1
This is all good, however,
# grep . /sys/devices/system/cpu/cpu*/topology/c*_id /sys/devices/system/cpu/cpu0/topology/cluster_id:0 /sys/devices/system/cpu/cpu0/topology/core_id:0 /sys/devices/system/cpu/cpu1/topology/cluster_id:0 /sys/devices/system/cpu/cpu1/topology/core_id:1 /sys/devices/system/cpu/cpu2/topology/cluster_id:0 /sys/devices/system/cpu/cpu2/topology/core_id:2 /sys/devices/system/cpu/cpu3/topology/cluster_id:0 /sys/devices/system/cpu/cpu3/topology/core_id:3 /sys/devices/system/cpu/cpu4/topology/cluster_id:8 /sys/devices/system/cpu/cpu4/topology/core_id:0 /sys/devices/system/cpu/cpu5/topology/cluster_id:8 /sys/devices/system/cpu/cpu5/topology/core_id:1 /sys/devices/system/cpu/cpu6/topology/cluster_id:8 /sys/devices/system/cpu/cpu6/topology/core_id:2 /sys/devices/system/cpu/cpu7/topology/cluster_id:8 /sys/devices/system/cpu/cpu7/topology/core_id:3
The core_id is broken as it is Module scope unique only. To get package scope unique core id, it should contain all bits up to package id bits.
thanks, rui
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