smpboot seems to be confused on dual EPYC system

Gabriel C
2018-05-20T13:24:05Z

Hello,

I have an H11DSi-NT board with 2 * EPYC 7281 16C/32T CPUs.

On that box for some reason spmboot things '4' logical packages
are possible.

Max CPUs can be 128 ( 2 * 32C/64T ), however only 2 CPUs are possible
not 4 and therefor there is no way to add other 64 hotplug CPUs.
( not even sure cpu hotplug will work here )

$ dmesg | egrep "smpboot|NR_CPUS|CPUs"
[ 0.000000] smpboot: Allowing 128 CPUs, 64 hotplug CPUs
[ 0.000000] setup_percpu: NR_CPUS:8192 nr_cpumask_bits:128
nr_cpu_ids:128 nr_node_ids:8
[ 0.000000] SLUB: HWalign=64, Order=0-3, MinObjects=0, CPUs=128, Nodes=8
[ 0.000000] RCU restricting CPUs from NR_CPUS=8192 to nr_cpu_ids=128.
[ 0.037000] smpboot: CPU0: AMD EPYC 7281 16-Core Processor (family:
0x17, model: 0x1, stepping: 0x2)
[ 0.048005] smp: Bringing up secondary CPUs ...
[ 0.055042] .... node #0, CPUs: #1 #2 #3
[ 0.079029] .... node #1, CPUs: #4 #5 #6 #7
[ 0.111049] .... node #2, CPUs: #8 #9 #10 #11
[ 0.143050] .... node #3, CPUs: #12 #13 #14 #15
[ 0.175031] .... node #4, CPUs: #16 #17 #18 #19
[ 0.217031] .... node #5, CPUs: #20 #21 #22 #23
[ 0.249062] .... node #6, CPUs: #24 #25 #26 #27
[ 0.281058] .... node #7, CPUs: #28 #29 #30 #31
[ 0.313028] .... node #0, CPUs: #32 #33 #34 #35
[ 0.345028] .... node #1, CPUs: #36 #37 #38 #39
[ 0.377046] .... node #2, CPUs: #40 #41 #42 #43
[ 0.409043] .... node #3, CPUs: #44 #45 #46 #47
[ 0.441028] .... node #4, CPUs: #48 #49 #50 #51
[ 0.473029] .... node #5, CPUs: #52 #53 #54 #55
[ 0.505060] .... node #6, CPUs: #56 #57 #58 #59
[ 0.537052] .... node #7, CPUs: #60 #61 #62 #63
[ 0.562171] smp: Brought up 8 nodes, 64 CPUs
[ 0.562171] smpboot: Max logical packages: 4
[ 0.562171] smpboot: Total of 64 processors activated (268089.53 BogoMIPS)

Can someone have a look ?

Best Regards,

Gabriel C