Ansible Role: Enable Huge Pages

Enable Huge Pages on Linux.

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Table of Contents

1. Requirements
2. Background
3. Installation
4. Role Variables
5. Dependencies
6. Example Playbook
7. Licensing
8. Author Information
9. Support
10. Contributing
11. Donation

Requirements

None.

Background

Enabling huge pages provide extra performance for your application. Only few apllications are supporting huge pages. When a process uses some memory, the CPU is marking the RAM as used by that process. For efficiency, the CPU allocate RAM by chunks of 4K bytes (it's the default value on many platforms). Those chunks are named pages. Those pages can be swapped to disk, etc.

Since the process address space are virtual, the CPU and the operating system have to remember which page belong to which process, and where it is stored. Obviously, the more pages you have, the more time it takes to find where the memory is mapped. When a process uses 1GB of memory, that's 262144 entries to look up (1GB / 4K). If one Page Table Entry consume 8bytes, that's 2MB (262144 * 8) to look-up.

Debian Wiki: Hugepages

Applications that support huge pages:

• Java
• MySQL
• PostgreSQL
• Memcached
• KVM
• XEN

Role Variables

Available variables are listed below, along with default values (see defaults/main.yml):

hugepages_system_group: hugepages

Name of group for access Huge Pages.

hugepages_system_member: tomcat

User who is member of Huge Pages group.

sysctl_d_path: "/etc/sysctl.d"

Location of sysctl.d folder.

hugepages_sysctl_filename: "90-hugepages.conf"

Name of sysstl.d file.

hugepages_number: 3072

Specify the number of large Huge Pages or large pages. In the following example 6 GB of a 8 GB system are reserved for large pages (assuming a large page size of 2048k (Hugepagesize: 2048 kB), then 6 GB = 6 x 1024 MB = 6291456 KB / 2048 KB = 3072):

Dependencies

None.

Example Playbook

- hosts: all
  roles:
    - hugepages

Licensing

The lactransformer application and documantations are licensed under the terms of the MIT / BSD, you will find a copy of this license in the LICENSE file included in the source package.

Author Information

This role was created in 2016-2018 by Kálmán Szalai - KAMI

Support

If you have any question, do not hesitate and drop me a line. If you found a bug, or have a feature request, you can fill an issue.

Using as a submudule of an AWX playbook

Add as a submodule

git submodule add --force [email protected]:KAMI911/ansible-role-hugepages.git roles/hugepages

Update as sumodule

Update only this submodule

git submodule update --remote roles/hugepages/

Update all submodules:

git submodule foreach git pull origin master

Contributing

There are many ways to contribute to ansible-role-hugepages -- whether it be sending patches, testing, reporting bugs, or reviewing and updating the documentation. Every contribution is appreciated!

Please continue reading in the contributing chapter.

Fork me on Github

SSH:

git@github.com:KAMI911/ansible-role-hugepages.git

HTTPS:

https://github.com/KAMI911/ansible-role-hugepages

Add a new remote upstream with this repository as value.

git remote add upstream https://github.com/KAMI911/ansible-role-hugepages.git

You can pull updates to your fork's master branch:

git fetch --all
git pull upstream HEAD

Donation

If you find this useful, please consider a donation: