Messages in this thread | | | From | Gabriel C <> | Date | Sun, 27 May 2018 23:37:10 +0200 | Subject | Re: smpboot seems to be confused on dual EPYC system |
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( sorry I didn't noticed google changed here something , resending to the list as plain text)
2018-05-27 23:22 GMT+02:00 Gabriel C <nix.or.die@gmail.com>: > > 2018-05-27 22:07 GMT+02:00 Borislav Petkov <bp@alien8.de>: >> >> On Sun, May 20, 2018 at 03:23:32PM +0200, Gabriel C wrote: >> > 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. >> >> First of all, which kernel? > > > That box runs right now 4.16.11 >> >> >> > 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 >> >> Your BIOS is made to support 32-Core CPUs too. > > > 128 CPUs are maximal possible however there is no way to have > 2 CPUs fully populated , in this case 64C and have another 64 hotplug CPUs > > That would mean that's an s4 system while impossible with EPYCs. >> >> >> > [ 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) >> >> That says 2 * 16C * 2T = 64T. > > > That says whole topology is set to 128 no ? > Eg to max possible but not to what the system runs now. > >> >> >> > [ 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) >> >> You have 64 logical CPUs. >> >> So what is the problem? >> > > The problem is that being wrong .. > > >[ 0.562171] smpboot: Max logical packages: 4 > > These are max 2 not 4. > > Regards >
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