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Transparent HugePages Settings
Note |
These settings are only applicable to the Zing Virtual Machine (ZVM) running in the ZST mode. |
If your operating system supports Transparent HugePages (THP), the THP feature must be turned off. For RHEL systems, see https://access.redhat.com/site/solutions/422283.
To disable Transparent HugePages on RHEL, SUSE, and Ubuntu systems:
- Check the current HugePage setting.
# cat /sys/kernel/mm/transparent_hugepage/enabled
Sample response.
[always] madvise never
- Open the grub configuration file for editing.
- For RHEL:
/boot/grub/grub.conf
- For SLES:
/boot/grub/menu.1st
- For Ubuntu:
/etc/default/grub
- Add
transparent_hugepage=never
to the kernel boot line, for example:
title Red Hat Enterprise Linux Server (2.6.32-431.el6.x86_64)
root (hd0,0)
kernel /vmlinuz-2.6.32-431.el6.x86_64 ro root=/dev/mapper/vg_qaesp3-lv_root rd_LVM_LV=vg_qaesp3
/lv_root rd_LVM_LV=vg_qaesp3/lv_swap rd_NO_LUKS rd_NO_MD rd_NO_DM LANG=en_US.UTF-8 SYSFONT=latarcyrheb-
sun16 KEYBOARDTYPE=pc KEYTABLE=us crashkernel=auto rhgb quiet transparent_hugepage=never
initrd /initramfs-2.6.32-431.el6.x86_64.img
- Reboot the server. This is required to have the change take effect.
- Check the change is applied after reboot.
# cat /sys/kernel/mm/transparent_hugepage/enabled
always madvise [never]
On RHEL/CentOS 7.x systems:
Follow the below steps to add the transparent_hugepage=never
kernel parameter in grub configuration file:
- Append or change the
transparent_hugepage=never
kernel parameter on theGRUB_CMDLINE_LINUX
option in/etc/sysconfig/grub
file . Save the file. For example,
GRUB_CMDLINE_LINUX="rd.lvm.lv=rhel/root rd.lvm.lv=rhel/swap vconsole.font=latarcyrheb-sun16 vconsole.keymap=us transparent_hugepage=never"
- Run the
grub2-mkconfig
command to regenerate thegrub.cfg
file. For example,
$ sudo grub2-mkconfig -o /boot/grub2/grub.cfg
- Reboot the system and ensure that the parameter is set correctly. This can be confirmed by running this command:
$ sudo cat /proc/cmdline
If THP are still not disabled, then continue with below steps:
- Create a customized tuned profile with disabled THP. The customized version will disable THP. Find out which profile is active, create a copy. In the following example we currently use the throughput-performance profile:
$ sudo tuned-adm active Current active profile: throughput-performance
- To create customized profile, create a new directory in
/etc/tuned
directory with desired profile name. For example,
$ sudo mkdir /etc/tuned/myprofile-nothp
- Then create a new
tuned.conf
file formyprofile-nothp
, and insert the new tuning info. For example,
$ sudo cat /etc/tuned/myprofile-nothp/tuned.conf [main] include= throughput-performance [vm] transparent_hugepages=never
- Make the script executable:
$ sudo chmod +x /etc/tuned/myprofile-nothp/tuned.conf
- Enable
myprofile
like so:
$ sudo tuned-adm profile myprofile-nothp
This change will immediately take effect and persist reboots. To verify if THP are disabled or not, run the following command:
$ sudo cat /sys/kernel/mm/transparent_hugepage/enabled
Alternatively, disable the tuned services. For example:
$ sudo systemctl stop tuned $ sudo systemctl disable tuned
or
$ sudo tuned-adm off
Now add transparent_hugepage=never
kernel parameter in grub configuration file as explained in above first method and reboot the server for changes to take effect.
See Also
- Zing System Tools Release Notes
- Zing with ZST System Requirements
- ZVM with ZST Installation Prerequisites Details
- Installing the Zing System Tools
- Installing the Zing Virtual Machine with ZST
- Installing Zing System Tools Using DKMS
- Verifying Zing Virtual Machine with ZST Installation
- Zing Virtual Machine with ZST Post Installation Tasks
- Run a Java Application with ZVM and ZST
- Zing Compatibility Reference
- Zing ZST Compatibility and API Versions
- ZST Memory Configuration
- Installing and Configuring Zing Using Read-Only Images
- Upgrading or Uninstalling Zing Components
- ZVM with ZST Monitoring and Management
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