ABOUT HUGE PAGES FOR ORACLE ADMINS

HUGE PAGES:

 

Overview of HugePages

 

## HugePages is a feature integrated into the Linux kernel 2.6. Enabling HugePages makes it possible for the operating system to support memory pages greater than the default (usually 4 KB).

## Using very large page sizes can improve system performance by reducing the number of system resources required to access page table entries.

## Huge Pages is useful for both 32-bit and 64-bit configurations.

## Huge Page sizes vary from 2 MB to 256 MB, depending on the kernel version and the hardware architecture.

## For Oracle Databases, using Huge Pages reduces the operating system maintenance of page states, and increases Translation Lookaside Buffer (TLB) hit ratio.

 

the command to get Hugepagesize from os prompt

1) grep Hugepagesize /proc/meminfo

Hugepagesize:       2048 kB

2) grep Huge /proc/meminfo

AnonHugePages:         0 kB

HugePages_Total:   14016

HugePages_Free:     6639

HugePages_Rsvd:     6613

HugePages_Surp:        0

Hugepagesize:       2048 kB

Transparent HugePages memory differs from standard HugePages memory because the kernel khugepaged thread allocates memory dynamically during runtime. Standard HugePages memory is pre-allocated at startup, and does not change during runtime.