ulimit:
Used to set user limits of system-wide resources. Provides control over resources available to the shell and processes started by it. Some common ulimit commands may include:
Disabling Linux services:
Certain Linux services may be disabled to minimize tasks that may consume CPU cycles.
irqbalance:
Disabled through "service irqbalance stop". Depending on the workload involved, the irqbalance service reassigns various IRQ's to system CPUs. Though this service might help in some situations, disabling it can also help environments which need to minimize or eliminate latency to more quickly respond to events.
Performance Governors (Linux):
In-kernel CPU frequency governors are pre-configured power schemes for the CPU. The CPUfreq governors use P-states to change frequencies and lower power consumption. The dynamic governors can switch between CPU frequencies, based on CPU utilization to allow for power savings while not sacrificing performance.
Other options beside a generic performance governor can be set, such as the Performance governor and Powersave governor:
--governor , -g
The governor defines the power characteristics of the system CPU, which in turn affects CPU performance. Each governor has its own unique behavior, purpose, and suitability in terms of workload.
On many Linux systems one can set the governor for all CPUs through the cpupower utility with following commands:
Tuning Kernel parameters:
The following Linux Kernel parameters were tuned to better optimize performance of some areas of the system:
tuned-adm:
The tuned-adm tool is a commandline interface for switching between different tuning profiles available to the tuned tuning daeomn available in supported Linux distros. The default configuration file is located in /etc/tuned.conf and the supported profiles can be found in /etc/tune-profiles.
Some profiles that may be available by default include: default, desktop-powersave, server-powersave, laptop-ac-powersave, laptop-battery-powersave, spindown-disk, throughput-performance, latency-performance, enterprise-storage
To set a profile, one can issue the command "tuned-adm profile (profile_name)". Here are details about relevant profiles.
Transparent Huge Pages (THP):
THP is an abstraction layer that automates most aspects of creating, managing, and using huge pages. THP is designed to hide much of the complexity in using huge pages from system administrators and developers, as normal huge pages must be assigned at boot time, can be difficult to manage manually, and often require significant changes to code in order to be used effectively. Transparent Hugepages increase the memory page size from 4 kilobytes to 2 megabytes. Transparent Hugepages provide significant performance advantages on systems with highly contended resources and large memory workloads. If memory utilization is too high or memory is badly fragmented which prevents hugepages being allocated, the kernel will assign smaller 4k pages instead. Most recent Linux OS releases have THP enabled by default.
Linux Huge Page settings:
If you need finer control and manually set the Huge Pages you can follow the below steps:
Note that further information about huge pages may be found in your Linux documentation file: /usr/src/linux/Documentation/vm/hugetlbpage.txt
]]>Model | Nominal TDP | Minimum cTDP | Maximum cTDP** |
---|---|---|---|
EPYC 7742 | 225 | 225 | 240 |
EPYC 7702 | 200 | 165 | 200 |
EPYC 7702P | 200 | 165 | 200 |
EPYC 7601 | 180 | 165 | 200 |
EPYC 7551 | 180 | 165 | 200 |
EPYC 7502 | 180 | 165 | 200 |
EPYC 7502P | 180 | 165 | 200 |
EPYC 7501 | 155/170 | 135 | 155/170* |
EPYC 7451 | 180 | 165 | 200 |
EPYC 7402 | 180 | 165 | 200 |
EPYC 7402P | 180 | 165 | 200 |
EPYC 7401 | 155/170 | 135 | 155/170* |
EPYC 7351 | 155/170 | 135 | 155/170* |
EPYC 7302 | 155 | 155 | 180 |
EPYC 7302P | 155 | 155 | 180 |
EPYC 7301 | 155/170 | 135 | 155/170* |
EPYC 7281 | 155/170 | 135 | 155/170* |
EPYC 7252 | 120 | 120 | 150 |
EPYC 7252P | 120 | 120 | 150 |
EPYC 7251 | 120 | 105 | 120 |
Last updated Dec. 19, 2019.
]]>