topic Re: Changing Page Size in Integrity Servers

Changing Page Size

Jim Hintze — Wed, 06 May 2009 17:48:08 GMT

While fully understanding that OpenVMS can not understand any page size other than 8192, How does one change the page size to a value other than 8192. Alpha ES45/ES40 answers are also welcome.

thanks
Jim

Re: Changing Page Size

Jozef_Novak — Thu, 07 May 2009 06:38:42 GMT

Hi Jim,

this is a question for OpenVMS forums, I believe.

J.

Re: Changing Page Size

Jim Hintze — Thu, 07 May 2009 13:27:38 GMT

Sorry I wasn't clear on the first post. this is an operating system independant question.

on either integrity (2660, 6600, 8640) or alpha (es40/es45), how does one change the page size?

thnaks
Jim

Re: Changing Page Size

Torsten. — Thu, 07 May 2009 13:45:37 GMT

Isn't it a kernel related setting?

From my hp-ux box:

# getconf PAGESIZE
4096

# kmtune -q vps_pagesize
Parameter Current Dyn Planned Module Version
===============================================================================
vps_pagesize 4 - 4

So it is not hardware related ;-))

See also (for hp-ux):

http://docs.hp.com/en/B3921-90010/vps_pagesize.5.html

Re: Changing Page Size

Jim Hintze — Thu, 07 May 2009 13:57:26 GMT

OK, conflicting info from another forum.
spot on, Thanks.

Re: Changing Page Size

Andrew C Fieldsend — Thu, 07 May 2009 14:06:07 GMT

The processor's Translation Lookaside Buffer (TLB) implementation defines the allowable values for the page size (see the relevant processor documentation for the details), but the operating system memory management code determines which values are actually used.

Actually, OpenVMS can understand other page sizes than 8k, but 8k is the default. See section 12.1 of the OpenVMS Programming Concepts Manual at http://www.openvms.compaq.com/doc/82final/5841/5841pro_038.html.

So it's both a hardware and operating system question;-)

Re: Changing Page Size

Jim Hintze — Thu, 07 May 2009 16:57:31 GMT

looking in circles here??

BOO$GQ_PAGE_SIZE = .HWRPB[HWRPB$IL_PAGESIZE_L];

MMG$GL_PAGE_SIZE is filled from BOO$GQ_PAGE_SIZE

while VMS may have the capacity to understand different values for BOO$GQ_PAGE_SIZE, Do I have the opportunity to set it anywhere??

Re: Changing Page Size

Andrew C Fieldsend — Thu, 07 May 2009 18:36:14 GMT

After some searching, I've found that the page size is set from the HWRPB (as you pointed out). The HWRPB is set up by the boot firmware, so if it is modifiable this will be the only place to do it - though I suspect it will be hardcoded in the firmware for each system, as it needs to be configured early in the boot process.