Fix grub on btrfs partition 

# mount the btrfs root subvolume
mount /dev/sda1 /mnt -o subvol=/

# (optional) set the default subvolume
btrfs sub set @ /mnt

mount /proc /mnt/proc --bind
mount /dev /mnt/dev --bind
mount /sys /mnt/sys --bind

chroot /mnt

grub-install /dev/sda
update-grub /dev/sda

# activate first partition
fdisk -l /dev/sda

Linpack under Ubuntu / Linux

Check latest LINPACK version
https://software.intel.com/en-us/articles/intel-mkl-benchmarks-suite

# https://software.intel.com/sites/default/files/managed/cc/19/l_mklb_p_2019.6.005.tgz

configure parameter

export MKL_DYNAMIC=false
export OMP_NUM_THREADS=4

Run LINPACK

wget https://raw.githubusercontent.com/panticz/scripts/master/run_linpack.sh -qO- | bash

[embed_url: https://raw.githubusercontent.com/panticz/scripts/master/run_linpack.sh]

Install LINPACK
[embed_url: https://raw.githubusercontent.com/panticz/installit/master/install.linpack.sh]

Get CPU info

CPU=$(cat /proc/cpuinfo | grep "model name" | tail -1)
COUNT=$(cat /proc/cpuinfo | grep processor | wc -l)

echo "
CPU   : ${CPU}
COUNT : ${COUNT}
"

Links
http://www.roylongbottom.org.uk/linpack%20results.htm

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