Day: June 28, 2020

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General Linux OS Tuning for AMD EPYC

Step 1: Turn off swap
Turn off swap to prevent accidental swapping. Do not that disabling swap without sufficient memory can have undesired effects

swapoff -a

Step 2: Turn off NUMA balancing
NUMA balancing can have undesired effects and since it is possible to bind the ranks and memory in HPC, this setting is not needed

echo 0 > /proc/sys/kernel/numa_balancing

Step 3: Disable ASLR (Address Space Layout Ranomization) is a security feature used to prevent the exploitation of memory vulnerabilities

echo 0 > /proc/sys/kernel/randomize_va_space

Step 4: Set CPU governor to performance and disable cc6. Setting the CPU perfomance to governor to perfomrnaces ensures max performances at all times. Disabling cc6 ensures that deeper CPU sleep states are not entered.

cpupower frequency-set -g performance
Setting cpu: 0
Setting cpu: 1
.....
.....
cpupower idle-set -d 2
Idlestate 2 disabled on CPU 0
Idlestate 2 disabled on CPU 1
Idlestate 2 disabled on CPU 2
.....
.....

References:

  1. Tuning Guard for AMD EPYC (pdf)
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Getting Useful Information on CPU and Configuration

Point 1. lscpu

To install

yum install util-linux

lscpu – (Print out information about CPU and its configuration)

[user1@myheadnode1 ~]$ lscpu
Architecture: x86_64
CPU op-mode(s): 32-bit, 64-bit
Byte Order: Little Endian
CPU(s): 32
On-line CPU(s) list: 0-31
Thread(s) per core: 2
Core(s) per socket: 8
Socket(s): 2
NUMA node(s): 2
Vendor ID: GenuineIntel
CPU family: 6
Model: 85
Model name: Intel(R) Xeon(R) Gold 6134 CPU @ 3.20GHz
Stepping: 4
CPU MHz: 3200.000
BogoMIPS: 6400.00
Virtualization: VT-x
L1d cache: 32K
L1i cache: 32K
L2 cache: 1024K
L3 cache: 25344K
NUMA node0 CPU(s): 0-7,16-23
NUMA node1 CPU(s): 8-15,24-31
Flags: fpu .................

Point 2: hwloc-ls

To install hwloc-ls

yum install hwloc

hwloc – (Prints out useful information about the NUMA locality of devices and general hardware locality information)

[user1@myheadnode1 ~]# hwloc-ls
Machine (544GB total)
NUMANode L#0 (P#0 256GB)
Package L#0 + L3 L#0 (25MB)
L2 L#0 (1024KB) + L1d L#0 (32KB) + L1i L#0 (32KB) + Core L#0
PU L#0 (P#0)
PU L#1 (P#16)
L2 L#1 (1024KB) + L1d L#1 (32KB) + L1i L#1 (32KB) + Core L#1
PU L#2 (P#1)
PU L#3 (P#17)
L2 L#2 (1024KB) + L1d L#2 (32KB) + L1i L#2 (32KB) + Core L#2
PU L#4 (P#2)
PU L#5 (P#18)
L2 L#3 (1024KB) + L1d L#3 (32KB) + L1i L#3 (32KB) + Core L#3
PU L#6 (P#3)
PU L#7 (P#19)
L2 L#4 (1024KB) + L1d L#4 (32KB) + L1i L#4 (32KB) + Core L#4
PU L#8 (P#4)
PU L#9 (P#20)
L2 L#5 (1024KB) + L1d L#5 (32KB) + L1i L#5 (32KB) + Core L#5
PU L#10 (P#5)
PU L#11 (P#21)
L2 L#6 (1024KB) + L1d L#6 (32KB) + L1i L#6 (32KB) + Core L#6
PU L#12 (P#6)
PU L#13 (P#22)
L2 L#7 (1024KB) + L1d L#7 (32KB) + L1i L#7 (32KB) + Core L#7
PU L#14 (P#7)
PU L#15 (P#23)
.....
.....
.....

Point 3 – Check whether the Boost is on for AMD

Print out if CPU boost is on or off

cat /sys/devices/system/cpu/cpufreq/boost
1

References:

  1. Tuning Guard for AMD EPYC (pdf)