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Enabling 2 GB Large Pages on Solaris 10

Giri Mandalika
Principal Software Engineer

Few facts:


  • - 8 KB is the default page size on Solaris 10 and 11 as of this writing
  • - both hardware and software must have support for 2 GB large pages
  • - SPARC T4 hardware is capable of supporting 2 GB pages
  • - Solaris 11 kernel has in-built support for 2 GB pages
  • - Solaris 10 has no default support for 2 GB pages
  • - Memory intensive 64-bit applications may benefit the most from using 2 GB pages

Prerequisites:

OS: Solaris 10 8/11 (Update 10) or later

Hardware: SPARC T4. eg., SPARC T4-1, T4-2 or T4-4

Steps to enable 2 GB large pages on Solaris 10:


  1. Install the latest kernel patch or ensure that 147440-04 or later was installed

  2. Add the following line to /etc/system and reboot
    • set max_uheap_lpsize=0x80000000

  3. Finally check the output of the following command when the system is back online
    • pagesize -a


    eg.,
    % pagesize -a
    8192

    <-- 8K
    65536

    <-- 64K
    4194304

    <-- 4M
    268435456

    <-- 256M
    2147483648

    <-- 2G
    % uname -a
    SunOS jar-jar 5.10 Generic_147440-21 sun4v sparc sun4v

Also See:


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Comments ( 1 )
  • David Thursday, August 30, 2012

    Why does one want to do this? What advantages to performance can one expect or deteriments?


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