Oracle Linux: 用於計算推薦的Linux HugePages/HugeTLB配置的值的Shell腳本(Doc ID 401749.1)

Oracle Linux: Shell Script to Calculate Values Recommended Linux HugePages / HugeTLB Configuration (Doc ID 401749.1)

APPLIES TO:

Oracle Database - Enterprise Edition
Oracle Database Cloud Schema Service - Version N/A and later
Oracle Database Exadata Cloud Machine - Version N/A and later
Oracle Cloud Infrastructure - Database Service - Version N/A and later
Oracle Database Cloud Exadata Service - Version N/A and later
Generic Linux

PURPOSE

This script is intended to compute values for the recommended HugePages/HugeTLB configuration for the current shared memory segments on Oracle Linux systems.
該腳本旨在爲Oracle Linux系統上的當前共享內存段計算推薦的HugePages / HugeTLB配置的值。
It does calculation for all shared memory segments available when the script is run, no matter it is an Oracle RDBMS shared memory segment or not.
無論腳本是否爲Oracle RDBMS共享內存段，它都會爲運行腳本時可用的所有共享內存段進行計算。
For general information about HugePages / HugeTLB, please see Note 361323.1

REQUIREMENTS

• Oracle Database instance(s) are up and running  Oracle數據庫實例已啓動並正在運行
• Oracle Database 11g Automatic Memory Management (AMM) is not setup  (See Note 749851.1) 未設置AMM
• The shared memory segments can be listed by command "ipcs -m"  共享內存段可以通過命令"ipcs -m"列出
• Oracle Linux   
• Package 'bc' installed  已安裝軟件包'bc'

CONFIGURING

1. Create a text file named hugepages_settings.sh  創建一個名爲hugepages_settings.sh的文本文件
2. Copy the contents below in the file  複製下面的內容到文件中
3. Run:
   $ chmod +x hugepages_settings.sh

INSTRUCTIONS

1. Be sure that all applications that are meant to use HugePage / HugeTLB are running at the time the script is to be run. This includes the Oracle RDBMS instances and ASM instances in addition to other applications.   確保在腳本運行時所有打算使用HugePage/HugeTLB的應用程序都在運行。除其他應用程序外，這還包括Oracle RDBMS實例和ASM實例。
2. Be sure that you have /bin and /usr/bin in $PATH  確保$PATH中有/bin和/usr/bin
3. Run:
   $ ./hugepages_settings.sh

CAUTION

This sample code is provided for educational purposes only, and is not supported by Oracle Support. It has been tested internally, however, we do not guarantee that it will work for you. Ensure that you run it in your test environment before using.

提供此示例代碼僅出於教育目的，Oracle Support不支持此示例代碼。它已經過內部測試，但是，我們不能保證它會爲您服務。使用前，請確保在測試環境中運行它。

SCRIPT

#!/bin/bash
#
# hugepages_settings.sh
#
# Linux bash script to compute values for the
# recommended HugePages/HugeTLB configuration
# on Oracle Linux
#
# Note: This script does calculation for all shared memory
# segments available when the script is run, no matter it
# is an Oracle RDBMS shared memory segment or not.
#
# This script is provided by Doc ID 401749.1 from My Oracle Support
# http://support.oracle.com

# Welcome text
echo "
This script is provided by Doc ID 401749.1 from My Oracle Support
(http://support.oracle.com) where it is intended to compute values for
the recommended HugePages/HugeTLB configuration for the current shared
memory segments on Oracle Linux. Before proceeding with the execution please note following:
 * For ASM instance, it needs to configure ASMM instead of AMM.
 * The 'pga_aggregate_target' is outside the SGA and
   you should accommodate this while calculating the overall size.
 * In case you changes the DB SGA size,
   as the new SGA will not fit in the previous HugePages configuration,
   it had better disable the whole HugePages,
   start the DB with new SGA size and run the script again.
And make sure that:
 * Oracle Database instance(s) are up and running
 * Oracle Database 11g Automatic Memory Management (AMM) is not setup
   (See Doc ID 749851.1)
 * The shared memory segments can be listed by command:
     # ipcs -m


Press Enter to proceed..."

read

# Check for the kernel version
KERN=`uname -r | awk -F. '{ printf("%d.%d\n",$1,$2); }'`

# Find out the HugePage size
HPG_SZ=`grep Hugepagesize /proc/meminfo | awk '{print $2}'`
if [ -z "$HPG_SZ" ];then
    echo "The hugepages may not be supported in the system where the script is being executed."
    exit 1
fi

# Initialize the counter
NUM_PG=0

# Cumulative number of pages required to handle the running shared memory segments
for SEG_BYTES in `ipcs -m | cut -c44-300 | awk '{print $1}' | grep "[0-9][0-9]*"`
do
    MIN_PG=`echo "$SEG_BYTES/($HPG_SZ*1024)" | bc -q`
    if [ $MIN_PG -gt 0 ]; then
        NUM_PG=`echo "$NUM_PG+$MIN_PG+1" | bc -q`
    fi
done

RES_BYTES=`echo "$NUM_PG * $HPG_SZ * 1024" | bc -q`

# An SGA less than 100MB does not make sense
# Bail out if that is the case
if [ $RES_BYTES -lt 100000000 ]; then
    echo "***********"
    echo "** ERROR **"
    echo "***********"
    echo "Sorry! There are not enough total of shared memory segments allocated for
HugePages configuration. HugePages can only be used for shared memory segments
that you can list by command:

    # ipcs -m

of a size that can match an Oracle Database SGA. Please make sure that:
 * Oracle Database instance is up and running
 * Oracle Database 11g Automatic Memory Management (AMM) is not configured"
    exit 1
fi

# Finish with results
case $KERN in
    '2.4') HUGETLB_POOL=`echo "$NUM_PG*$HPG_SZ/1024" | bc -q`;
           echo "Recommended setting: vm.hugetlb_pool = $HUGETLB_POOL" ;;
    '2.6') echo "Recommended setting: vm.nr_hugepages = $NUM_PG" ;;
    '3.8') echo "Recommended setting: vm.nr_hugepages = $NUM_PG" ;;
    '3.10') echo "Recommended setting: vm.nr_hugepages = $NUM_PG" ;;
    '4.1') echo "Recommended setting: vm.nr_hugepages = $NUM_PG" ;;
    '4.14') echo "Recommended setting: vm.nr_hugepages = $NUM_PG" ;;
    *) echo "Kernel version $KERN is not supported by this script (yet). Exiting." ;;
esac

# End

SAMPLE OUTPUT

For 2.4 kernel systems:  對於2.4內核系統

$ ./hugepages_settings.sh
...
Recommended setting: vm.hugetlb_pool = 764

For 2.6 and later kernel systems:  對於2.6及更高版本的內核系統

$ ./hugepages_settings.sh
...
Recommended setting: vm.nr_hugepages = 67

Please see Document 361323.1 about how to do that setting.

REFERENCES

NOTE:361323.1 - HugePages on Linux: What It Is... and What It Is Not...