Tunable Base Page Size

ManualsBrandsHP ManualsSoftwareHP-UX 11i v3 Foundation OE

Table of Contents

Executive summary ............................................................................................................................... 1

What is Tunable Base Page Size?.......................................................................................................... 1

How Base Page Size Affects the System ................................................................................................. 1

Integrity Virtual Machines Platform Manager ....................................................................................... 2

Working with Tunable Base Page Size ................................................................................................... 2

Tuning the base page size ................................................................................................................ 2

base_pagesize kernel tunable parameter ........................................................................................ 2

Static tuning only ............................................................................................................................. 3

Installing Tunable Base Page Size enhancement ...................................................................................... 3

Updating the HP-UX core .................................................................................................................. 3

Updating system utilities .................................................................................................................... 3

Updating applications ...................................................................................................................... 4

Known limitations ............................................................................................................................. 4

Java Virtual Machine .................................................................................................................... 4

HFS Filesystem ............................................................................................................................. 4

Performance considerations .................................................................................................................. 5

Summary ............................................................................................................................................ 5

Appendices......................................................................................................................................... 6

Application programming for tunable base pages ................................................................................ 6

Obsolete programming constructs .................................................................................................. 6

Proper programming practices ....................................................................................................... 6

Application compatibility .................................................................................................................. 7

Oracle Database Manager ............................................................................................................ 7

SAP ERP product .......................................................................................................................... 7

SAS ............................................................................................................................................ 7

Tuxedo ........................................................................................................................................ 7

Veritas Enterprise Services Administrator ......................................................................................... 7

WebLogic 9.1 ............................................................................................................................. 7

WebSphere 6.1 ........................................................................................................................... 7

For more information ............................................................................................................................ 8

Tunable Base Page Size

Summary of content (9 pages)

PAGE 1
Tunable Base Page Size Table of Contents Executive summary............................................................................................................................... 1 What is Tunable Base Page Size?.......................................................................................................... 1 How Base Page Size Affects the System ................................................................................................. 1 Integrity Virtual Machines Platform Manager .
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Executive summary Tunable Base Page Size is a new feature introduced in update 3 to HP-UX 11i v3. The system administrator can now adjust the size of a base page used in managing system memory, by invoking the kctune command to change the tunable base_pagesize and then rebooting the system. The larger base page sizes allow memory to be managed more efficiently, resulting in a decrease in kernel memory usage. This can also result in an increase in system performance for some workloads.
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Figure 1: Kernel memory overhead as a function of base page size Integrity Virtual Machines Platform Manager The Integrity Virtual Machines Host, also called the Platform Manager, derives great benefit from using 64 kB base pages. The Host automatically tunes the base page size appropriately. Under no circumstances should the base page size for the Integrity Virtual Machines Host be changed to any value other than 64 kB.
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Static tuning only The base_pagesize tunable is not dynamic: any change requires a reboot to take effect. Installing Tunable Base Page Size enhancement The code to enable the Tunable Base Page Size enhancement is available as a set of patches in Update 3 to HP-UX 11i v3. Updating the HP-UX core All of the files needed to update the HP-UX 11i v3 core for the Tunable Base Page Size enhancement are installed as a consequence of installing the patch PHKL_38038. A reboot following installation is required.
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Updating applications While most applications are not sensitive to the base page size, some applications will not operate properly when the base page size is tuned to a value larger than the default. Some applications implicitly assume that the size of a base page is 4 kB. This assumption may lead to inappropriate sizes for data objects created by the application.
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Note 1 The default block size for the HFS filesystem is 8kB. HFS filesystems created with a filesystem block size at least equal to the base page size function correctly. HFS filesystems configured with a 64k block size (and an 8k fragment size) will work with any supported base page size. Please refer to the mkfs_hfs(1M) manpage for complete details. Performance considerations The kernel operations that manage virtual memory on behalf of applications are more efficient when the base page size is larger.
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Appendices Application programming for tunable base pages The standards-based interfaces needed to obtain the base page size of the underlying system have long existed in HP-UX. Most portable application code already uses these interfaces. Some applications, however, may still rely on hard-coded notions of the system base page size. This document provides example code that can replace many legacy idioms in a page size independent manner. The getconf(1) command provides this capability for use in scripting.
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Application compatibility HP performs Customer Usage Testing on each update. The results of that testing for HP-UX 11i v3 Update 3 are summarized below. The material in this section will be updated as the details change. The most current version of this document is available online at http://docs.hp.com/en/en/14670/ENW-TBPS-TW.pdf .
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For more information See the HP-UX manpage base_pagesize(5) for details about the base_pagesize tunable. See the manpage kctune(1M) for information about tuning kernel parameters. See the manpage getconf(1) for details of obtaining system configuration information, such as base page size. To help us improve our documents, please provide feedback at www.hp.com/solutions/feedback Technology for better business outcomes © Copyright 2008 Hewlett-Packard Development Company, L.P.