Bug#965263: debian-installer: Script exected in preseed/late_command on dual CPU socket system sees only Single CPU socket
Package: debian-installer
Severity: normal
Dear Maintainer,
I recently moved some code to preseed/late_command script to do the CPU pinning for host machine.
Script snippet looks something like below
NODE_CPUS=2
for node in /sys/devices/system/node/node[0-9]; do
cat $node/cpu[0-9]*/topology/thread_siblings_list | sort -nu | sed 's/,/\n/' | head -n$NODE_CPUS
done
It captured a sibling core from only node0 of the system. So out of curiosity I observed the logs we captured
on rsyslog server and found what I see below
Jul 14 09:45:18 10.33.97.110 in-target: ++ cat /sys/devices/system/node/node0/cpu0/topology/thread_siblings_list /sys/devices/system/node/node0/cpu10/topology/thread_siblings_list /sys/devices/system/no
de/node0/cpu11/topology/thread_siblings_list /sys/devices/system/node/node0/cpu12/topology/thread_siblings_list /sys/devices/system/node/node0/cpu13/topology/thread_siblings_list /sys/devices/system/nod
e/node0/cpu14/topology/thread_siblings_list /sys/devices/system/node/node0/cpu15/topology/thread_siblings_list /sys/devices/system/node/node0/cpu16/topology/thread_siblings_list /sys/devices/system/node
/node0/cpu17/topology/thread_siblings_list /sys/devices/system/node/node0/cpu18/topology/thread_siblings_list /sys/devices/system/node/node0/cpu19/topology/thread_siblings_list /sys/devices/system/node/
node0/cpu1/topology/thread_siblings_list /sys/devices/system/node/node0/cpu20/topology/thread_siblings_list /sys/devices/system/node/node0/cpu21/topology/thread_siblings_list /sys/devices/system/node/no
de0/cpu22/topology/thr
Jul 14 09:45:18 10.33.97.110 in-target: system/node/node0/cpu23/topology/thread_siblings_list /sys/devices/system/node/node0/cpu24/topology/thread_siblings_list /sys/devices/system/node/node0/cpu25/topo
logy/thread_siblings_list /sys/devices/system/node/node0/cpu26/topology/thread_siblings_list /sys/devices/system/node/node0/cpu27/topology/thread_siblings_list /sys/devices/system/node/node0/cpu28/topol
ogy/thread_siblings_list /sys/devices/system/node/node0/cpu29/topology/thread_siblings_list /sys/devices/system/node/node0/cpu2/topology/thread_siblings_list /sys/devices/system/node/node0/cpu30/topolog
y/thread_siblings_list /sys/devices/system/node/node0/cpu31/topology/thread_siblings_list /sys/devices/system/node/node0/cpu32/topology/thread_siblings_list /sys/devices/system/node/node0/cpu33/topology
/thread_siblings_list /sys/devices/system/node/node0/cpu34/topology/thread_siblings_list /sys/devices/system/node/node0/cpu35/topology/thread_siblings_list /sys/devices/system/node/node0/cpu36/topology/
thread_siblings_list /
Jul 14 09:45:18 10.33.97.110 in-target: pu37/topology/thread_siblings_list /sys/devices/system/node/node0/cpu38/topology/thread_siblings_list /sys/devices/system/node/node0/cpu39/topology/thread_sibling
s_list /sys/devices/system/node/node0/cpu3/topology/thread_siblings_list /sys/devices/system/node/node0/cpu40/topology/thread_siblings_list /sys/devices/system/node/node0/cpu41/topology/thread_siblings_
list /sys/devices/system/node/node0/cpu42/topology/thread_siblings_list /sys/devices/system/node/node0/cpu43/topology/thread_siblings_list /sys/devices/system/node/node0/cpu44/topology/thread_siblings_l
ist /sys/devices/system/node/node0/cpu45/topology/thread_siblings_list /sys/devices/system/node/node0/cpu46/topology/thread_siblings_list /sys/devices/system/node/node0/cpu47/topology/thread_siblings_li
st /sys/devices/system/node/node0/cpu48/topology/thread_siblings_list /sys/devices/system/node/node0/cpu49/topology/thread_siblings_list /sys/devices/system/node/node0/cpu4/topology/thread_siblings_list
/sys/devices/system/n
Jul 14 09:45:18 10.33.97.110 in-target: _siblings_list /sys/devices/system/node/node0/cpu51/topology/thread_siblings_list /sys/devices/system/node/node0/cpu52/topology/thread_siblings_list /sys/devices/
system/node/node0/cpu53/topology/thread_siblings_list /sys/devices/system/node/node0/cpu54/topology/thread_siblings_list /sys/devices/system/node/node0/cpu55/topology/thread_siblings_list /sys/devices/s
ystem/node/node0/cpu56/topology/thread_siblings_list /sys/devices/system/node/node0/cpu57/topology/thread_siblings_list /sys/devices/system/node/node0/cpu58/topology/thread_siblings_list /sys/devices/sy
stem/node/node0/cpu59/topology/thread_siblings_list /sys/devices/system/node/node0/cpu5/topology/thread_siblings_list /sys/devices/system/node/node0/cpu60/topology/thread_siblings_list /sys/devices/syst
em/node/node0/cpu61/topology/thread_siblings_list /sys/devices/system/node/node0/cpu62/topology/thread_siblings_list /sys/devices/system/node/node0/cpu63/topology/thread_siblings_list /sys/devices/syste
m/node/node0/cpu64/top
Jul 14 09:45:18 10.33.97.110 in-target: /devices/system/node/node0/cpu65/topology/thread_siblings_list /sys/devices/system/node/node0/cpu66/topology/thread_siblings_list /sys/devices/system/node/node0/c
pu67/topology/thread_siblings_list /sys/devices/system/node/node0/cpu68/topology/thread_siblings_list /sys/devices/system/node/node0/cpu69/topology/thread_siblings_list /sys/devices/system/node/node0/cp
u6/topology/thread_siblings_list /sys/devices/system/node/node0/cpu70/topology/thread_siblings_list /sys/devices/system/node/node0/cpu71/topology/thread_siblings_list /sys/devices/system/node/node0/cpu7
2/topology/thread_siblings_list /sys/devices/system/node/node0/cpu73/topology/thread_siblings_list /sys/devices/system/node/node0/cpu74/topology/thread_siblings_list /sys/devices/system/node/node0/cpu75
/topology/thread_siblings_list /sys/devices/system/node/node0/cpu76/topology/thread_siblings_list /sys/devices/system/node/node0/cpu77/topology/thread_siblings_list /sys/devices/system/node/node0/cpu78/
topology/thread_siblin
Jul 14 09:45:18 10.33.97.110 in-target: e/node0/cpu79/topology/thread_siblings_list /sys/devices/system/node/node0/cpu7/topology/thread_siblings_list /sys/devices/system/node/node0/cpu80/topology/thread
_siblings_list /sys/devices/system/node/node0/cpu81/topology/thread_siblings_list /sys/devices/system/node/node0/cpu82/topology/thread_siblings_list /sys/devices/system/node/node0/cpu83/topology/thread_
siblings_list /sys/devices/system/node/node0/cpu84/topology/thread_siblings_list /sys/devices/system/node/node0/cpu85/topology/thread_siblings_list /sys/devices/system/node/node0/cpu86/topology/thread_s
iblings_list /sys/devices/system/node/node0/cpu87/topology/thread_siblings_list /sys/devices/system/node/node0/cpu88/topology/thread_siblings_list /sys/devices/system/node/node0/cpu89/topology/thread_si
blings_list /sys/devices/system/node/node0/cpu8/topology/thread_siblings_list /sys/devices/system/node/node0/cpu90/topology/thread_siblings_list /sys/devices/system/node/node0/cpu91/topology/thread_sibl
ings_list /sys/devices
Jul 14 09:45:18 10.33.97.110 in-target: gy/thread_siblings_list /sys/devices/system/node/node0/cpu93/topology/thread_siblings_list /sys/devices/system/node/node0/cpu94/topology/thread_siblings_list /sys
/devices/system/node/node0/cpu95/topology/thread_siblings_list /sys/devices/system/node/node0/cpu9/topology/thread_siblings_list
As you can see all core appears to be in node0 but once system is installed and booted. In lscpu and numactl we see following output.
NUMA node0 CPU(s): 0-23,48-71
NUMA node1 CPU(s): 24-47,72-95
node 0 cpus: 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71
node 1 cpus: 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95
I'm bit surprised by this behavior as intended system all came up with single core (2thread) instead of 2 core (4thread).
Is this expected behavior? Do I need to do any specific configuration to make sure CPU is visible across nodes?.
Please let me know if you need more information.
Warm Regards,
Vasudev
-- System Information:
Debian Release: bullseye/sid
APT prefers unstable-debug
APT policy: (500, 'unstable-debug'), (500, 'unstable'), (1, 'experimental-debug'), (1, 'experimental')
Architecture: amd64 (x86_64)
Foreign Architectures: armhf, arm64
Kernel: Linux 5.6.0-2-amd64 (SMP w/8 CPU cores)
Kernel taint flags: TAINT_WARN, TAINT_OOT_MODULE, TAINT_UNSIGNED_MODULE
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8), LANGUAGE= (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled
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