Commit ef7719d8 authored by Alejandro Homs Puron's avatar Alejandro Homs Puron Committed by operator for beamline
Browse files

Doc: add the maxcpus Linux kernel option

parent b0f9fe78
......@@ -389,6 +389,36 @@ Tune the OS network buffer sizes:
# Size of per-device buffer (in packets) before Linux kernel dispatching
net.core.netdev_max_backlog = 262144
Linux *maxcpus* option
~~~~~~~~~~~~~~~~~~~~~~
The *Supermicro* BIOS does not always acknowledge the *Disable Hyper-Threading* option,
so after some reboot conditions the Hyper-Threading is activated and Linux sees twice the
number of CPUs. The only way to control this is to limit the number of CPUs used by
Linux in the kernel command line.
Edit the */etc/default/grub* file and add *maxcpus=12* to the *GRUB_CMDLINE_LINUX_DEFAULT*
variable and force the update *GRUB* configuration file:
::
# as root
lid10eiger1:~ # cat /etc/default/grub
# If you change this file, run 'update-grub' afterwards to update
# /boot/grub/grub.cfg.
# For full documentation of the options in this file, see:
# info -f grub -n 'Simple configuration'
GRUB_DEFAULT=0
GRUB_TIMEOUT=5
GRUB_DISTRIBUTOR=`lsb_release -i -s 2> /dev/null || echo Debian`
GRUB_CMDLINE_LINUX_DEFAULT="ipv6.disable=1 quiet maxcpus=12"
GRUB_CMDLINE_LINUX=""
...
lid10eiger1:~ # update-grub
...
Network configuration
---------------------
......
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