4

--- UPDATE 2 --- Never solved for Xcp-Ng 7.6. Issue does not exist with xcp-ng 8.0.


I have a Intel Xeon X5650 processor (from eBay) but linux (Xcp-ng 7.6) only lists 8 using lscpu. However dmidecode -t processor correctly states 6 cores & 12 threads.

I have tried updating the BIOS and Xcp-Ng and adding maxcpus=12 nr_cpus=12 to the kernel line. Unfortunately I have no idea what could be causing this or how to continue searching for a solution.

--- UPDATE ---- Disabling hyperthreading gives me 6 cores but only 1 thread per core -- /UPDATE ---

Machine (HP ProLiant DL320 G6) info (BIOS boot messages):

32 GB Installed
ProLiant System BIOS - W07 (05/21/2018)

1 Processor(s) detected, 6 total cores enabled, Hyperthreading is enabled Proc 1: Intel(R) Xeon(R) CPU X5650 @ 2.67GHz QPI Speed: 6.4 GT/s

outputs (some partial) from lscpu, dmesg, /proc/cpuinfo, uname, dmidecode

[root@xcp-ng ~]# lscpu
Architecture:          x86_64
CPU op-mode(s):        32-bit, 64-bit
Byte Order:            Little Endian
CPU(s):                8
On-line CPU(s) list:   0-7
Thread(s) per core:    2
Core(s) per socket:    4
Socket(s):             1
Vendor ID:             GenuineIntel
CPU family:            6
Model:                 44
Model name:            Intel(R) Xeon(R) CPU           X5650  @ 2.67GHz
Stepping:              2
CPU MHz:               2666.766
BogoMIPS:              5333.53
Hypervisor vendor:     Xen
Virtualization type:   none
L1d cache:             32K
L1i cache:             32K
L2 cache:              256K
L3 cache:              12288K

[root@xcp-ng ~]# uname -a
Linux xcp-ng 4.4.0+10 #1 SMP Thu Sep 13 08:55:11 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux

[root@xcp-ng ~]# cat /proc/cpuinfo 
processor   : 0
vendor_id   : GenuineIntel
cpu family  : 6
model       : 44
model name  : Intel(R) Xeon(R) CPU           X5650  @ 2.67GHz
stepping    : 2
microcode   : 0x1f
cpu MHz     : 2666.766
cache size  : 12288 KB
physical id : 1
siblings    : 8
core id     : 0
cpu cores   : 4
apicid      : 32
initial apicid  : 32
fpu     : yes
fpu_exception   : yes
cpuid level : 11
wp      : yes
flags       : fpu de tsc msr pae mce cx8 apic sep mca cmov pat clflush acpi mmx fxsr sse sse2 ht syscall nx lm constant_tsc arch_perfmon rep_good nopl nonstop_tsc pni pclmulqdq monitor est ssse3 cx16 sse4_1 sse4_2 popcnt aes hypervisor lahf_lm ida arat epb dtherm
bugs        : l1tf
bogomips    : 5333.53
clflush size    : 64
cache_alignment : 64
address sizes   : 40 bits physical, 48 bits virtual
power management:
...

[root@xcp-ng ~]# dmesg | grep -i cpu
[    0.000000] Initializing cgroup subsys cpuset
[    0.000000] Initializing cgroup subsys cpu
[    0.000000] Initializing cgroup subsys cpuacct
[    0.000000] Command line: root=LABEL=root-aflmjv ro nolvm hpet=disable xencons=hvc console=hvc0 console=tty0 quiet vga=785 splash pti=off spectre_v2=off l1tf=off nospec_store_bypass_disable no_stf_barrier noibrs noibpb nospectre_v1 nospectre_v2 mds=off slub_debug maxcpus=12 nr_cpus=12
[    0.000000] KERNEL supported cpus:
[    0.000000] smpboot: Allowing 12 CPUs, 0 hotplug CPUs
[    0.000000] setup_percpu: NR_CPUS:64 nr_cpumask_bits:64 nr_cpu_ids:12 nr_node_ids:1
[    0.000000] PERCPU: Embedded 32 pages/cpu @ffff88007ce00000 s92120 r8192 d30760 u131072
[    0.000000] pcpu-alloc: s92120 r8192 d30760 u131072 alloc=1*2097152
[    0.000000] pcpu-alloc: [0] 00 01 02 03 04 05 06 07 08 09 10 11 -- -- -- -- 
[    0.000000] Kernel command line: root=LABEL=root-aflmjv ro nolvm hpet=disable xencons=hvc console=hvc0 console=tty0 quiet vga=785 splash pti=off spectre_v2=off l1tf=off nospec_store_bypass_disable no_stf_barrier noibrs noibpb nospectre_v1 nospectre_v2 mds=off slub_debug maxcpus=12 nr_cpus=12
[    0.000000] SLUB: HWalign=64, Order=0-3, MinObjects=0, CPUs=8, Nodes=1
[    0.000000]  RCU restricting CPUs from NR_CPUS=64 to nr_cpu_ids=8.
[    0.000000] RCU: Adjusting geometry for rcu_fanout_leaf=64, nr_cpu_ids=8
[    0.000000] Xen: using vcpuop timer interface
[    0.000000] installing Xen timer for CPU 0
[   27.992808] CPU: Physical Processor ID: 1
[   27.992809] CPU: Processor Core ID: 0
[   27.992812] mce: CPU supports 2 MCE banks
[   28.003577] cpu 0 spinlock event irq 49
[   28.003582] Could not initialize VPMU for cpu 0, error -95
[   28.005495] NMI watchdog: disabled (cpu0): hardware events not enabled
[   28.005496] NMI watchdog: Shutting down hard lockup detector on all cpus
[   28.005838] installing Xen timer for CPU 1
[   28.005877] cpu 1 spinlock event irq 56
[   28.006600] installing Xen timer for CPU 2
[   28.006641] cpu 2 spinlock event irq 63
[   28.007293] installing Xen timer for CPU 3
[   28.007329] cpu 3 spinlock event irq 70
[   28.007994] installing Xen timer for CPU 4
[   28.008032] cpu 4 spinlock event irq 77
[   28.008682] installing Xen timer for CPU 5
[   28.008721] cpu 5 spinlock event irq 84
[   28.009375] installing Xen timer for CPU 6
[   28.009412] cpu 6 spinlock event irq 91
[   28.010057] installing Xen timer for CPU 7
[   28.010096] cpu 7 spinlock event irq 98
[   28.010368] x86: Booted up 1 node, 8 CPUs
[   40.874621] pcc-cpufreq: (v1.10.00) driver loaded with frequency limits: 1600 MHz, 2666 MHz
[   40.924382] pcc-cpufreq: (v1.10.00) driver loaded with frequency limits: 1600 MHz, 2666 MHz
[   40.955884] pcc-cpufreq: (v1.10.00) driver loaded with frequency limits: 1600 MHz, 2666 MHz
[   40.988112] pcc-cpufreq: (v1.10.00) driver loaded with frequency limits: 1600 MHz, 2666 MHz
[   41.029176] pcc-cpufreq: (v1.10.00) driver loaded with frequency limits: 1600 MHz, 2666 MHz
[   41.069384] pcc-cpufreq: (v1.10.00) driver loaded with frequency limits: 1600 MHz, 2666 MHz
[   41.118143] pcc-cpufreq: (v1.10.00) driver loaded with frequency limits: 1600 MHz, 2666 MHz
[   50.796328] pcc-cpufreq: (v1.10.00) driver loaded with frequency limits: 1600 MHz, 2666 MHz
[   50.886595] pcc-cpufreq: (v1.10.00) driver loaded with frequency limits: 1600 MHz, 2666 MHz
[   50.971893] pcc-cpufreq: (v1.10.00) driver loaded with frequency limits: 1600 MHz, 2666 MHz
[   51.036407] pcc-cpufreq: (v1.10.00) driver loaded with frequency limits: 1600 MHz, 2666 MHz

[root@xcp-ng ~]# dmidecode -t processor
# dmidecode 2.12-dmifs
SMBIOS 2.7 present.

Handle 0x0400, DMI type 4, 42 bytes
Processor Information
    Socket Designation: Proc 1
    Type: Central Processor
    Family: Xeon
    Manufacturer: Intel
    ID: C2 06 02 00 FF FB EB BF
    Signature: Type 0, Family 6, Model 44, Stepping 2
    Flags:
        FPU (Floating-point unit on-chip)
        VME (Virtual mode extension)
        DE (Debugging extension)
        PSE (Page size extension)
        TSC (Time stamp counter)
        MSR (Model specific registers)
        PAE (Physical address extension)
        MCE (Machine check exception)
        CX8 (CMPXCHG8 instruction supported)
        APIC (On-chip APIC hardware supported)
        SEP (Fast system call)
        MTRR (Memory type range registers)
        PGE (Page global enable)
        MCA (Machine check architecture)
        CMOV (Conditional move instruction supported)
        PAT (Page attribute table)
        PSE-36 (36-bit page size extension)
        CLFSH (CLFLUSH instruction supported)
        DS (Debug store)
        ACPI (ACPI supported)
        MMX (MMX technology supported)
        FXSR (FXSAVE and FXSTOR instructions supported)
        SSE (Streaming SIMD extensions)
        SSE2 (Streaming SIMD extensions 2)
        SS (Self-snoop)
        HTT (Multi-threading)
        TM (Thermal monitor supported)
        PBE (Pending break enabled)
    Version: Intel(R) Xeon(R) CPU X5650 @ 2.67GHz            
    Voltage: 1.4 V
    External Clock: 133 MHz
    Max Speed: 4800 MHz
    Current Speed: 2667 MHz
    Status: Populated, Enabled
    Upgrade: Socket LGA1366
    L1 Cache Handle: 0x0710
    L2 Cache Handle: 0x0720
    L3 Cache Handle: 0x0730
    Serial Number: Not Specified
    Asset Tag: Not Specified
    Part Number: Not Specified
    Core Count: 6
    Core Enabled: 6
    Thread Count: 12
    Characteristics:
        64-bit capable
1
  • This will happen to you again when XCP gets updated again, I think is due to meltdown/spectre bug on old CPUs, then XCP degrades their performance (reduces cores available to user) – Gabriel Jun 1 at 22:40
0

Did yum update fix anything? Fresh Installation of xcp-ng or did this have an old CPU and then upgraded with the new cpu?

1
  • 1
    A fresh installation of Xcp-ng version 8.0 solved the issue. Fresh install of 7.6 did not help. – Octetz Dec 30 '19 at 22:20

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