From: Borislav Petkov <bp@alien8.de>
To: Gabriel C <nix.or.die@gmail.com>
Cc: LKML <linux-kernel@vger.kernel.org>, X86 ML <x86@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>
Subject: Re: smpboot seems to be confused on dual EPYC system
Date: Sun, 27 May 2018 22:07:08 +0200 [thread overview]
Message-ID: <20180527200707.GC6349@zn.tnic> (raw)
In-Reply-To: <CAEJqkgjMdeeiF+apcAGKdOJQRvaq8SLFsS2dvpuapY1DQn6oTA@mail.gmail.com>
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?
> 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.
> [ 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.
> [ 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?
--
Regards/Gruss,
Boris.
Good mailing practices for 400: avoid top-posting and trim the reply.
next prev parent reply other threads:[~2018-05-27 20:07 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-20 13:23 smpboot seems to be confused on dual EPYC system Gabriel C
2018-05-27 20:07 ` Borislav Petkov [this message]
[not found] ` <CAEJqkggtUvpfRjUUxQDx8tgV50NHayc=2nRTDNeWq83pZThsUQ@mail.gmail.com>
2018-05-27 21:37 ` Gabriel C
2018-05-27 22:51 ` Gabriel C
2018-05-27 23:16 ` Borislav Petkov
2018-05-27 23:25 ` Gabriel C
2018-05-27 23:05 ` Borislav Petkov
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