Enabling 2 GB Large Pages on Solaris 10

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 capabile 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
   

   • Check the patch download instructions

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:

• Solaris 9 or later: More performance with Large Pages (MPSS)
  
• Large page support for instructions (text) in Solaris 10 1/06
  
• Solaris: How To Disable Out Of The Box (OOB) Large Page Support?
  
• Memory fragmentation / Large Pages on Solaris x86
  

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