4.2. tuned and tuned-adm

tuned is a tuning profile delivery mechanism that adapts Red Hat Enterprise Linux for certain workload characteristics, such as requirements for CPU-intensive tasks, or storage/network throughput responsiveness. It can react to changes in CPU and network use and adjust settings to improve performance in active devices, or reduce power consumption in inactive devices.
The accompanying ktune partners with the tuned-adm tool to provide a number of tuning profiles that are pre-configured to enhance performance and reduce power consumption in a number of specific use cases. Edit these profiles or create new profiles to create performance solutions tailored to your environment.
The virtualization-related profiles provided as part of tuned-adm include:
virtual-guest
Based on the enterprise-storage profile, virtual-guest also decreases the swappiness of virtual memory. This profile is available in Red Hat Enterprise Linux 6.3 and later, and is the recommended profile for guest machines.
virtual-host
Based on the enterprise-storage profile, virtual-host also decreases the swappiness of virtual memory and enables more aggressive writeback of dirty pages. This profile is available in Red Hat Enterprise Linux 6.3 and later, and is the recommended profile for virtualization hosts, including both KVM and Red Hat Enterprise Virtualization hosts.
Install the tuned package and its associated systemtap scripts with the command:
yum install tuned
Installing the tuned package also sets up a sample configuration file at /etc/tuned.conf and activates the default profile.
Start tuned by running:
service tuned start
To start tuned every time the machine boots, run:
chkconfig tuned on
To list all available profiles and identify the current active profile, run:
# tuned-adm list
Available profiles:
- latency-performance
- sap
- virtual-guest
- laptop-battery-powersave
- virtual-host
- enterprise-storage
- desktop-powersave
- spindown-disk
- default
- throughput-performance
- laptop-ac-powersave
- server-powersave
Current active profile: default
To only display the currently active profile, run:
tuned-adm active
To switch to one of the available profiles, run:
tuned-adm profile profile_name
For example, to switch to the virtual-host profile, run:
tuned-adm profile virtual-host

Note

It is possible to create custom tuned profiles to encapsulate a set of tuning parameters. For instructions on creating custom tuned profiles, refer to the tuned.conf man page.
In some cases, it is preferable to disable tuned to use parameters set manually. To disable all tuning, run:
tuned-adm off

Note

Refer to the Red Hat Enterprise Linux 6 Power Management Guide for further information about tuned, tuned-adm and ktune.