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Date: Sat, 7 Nov 2009 11:09:35 +0100
From: Gary Jennejohn <gary.jennejohn@freenet.de>
To: Trever <anti_spamsys@yahoo.com>
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Cc: freebsd-hackers@freebsd.org
Subject: Re: Why is default value of NKPT so small?  mfsroot
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On Fri, 6 Nov 2009 11:19:51 -0800 (PST)
Trever <anti_spamsys@yahoo.com> wrote:

> Does anyone know what the thinking is behind the default value of NKTP in /usr/src/sys/i386/include/pmap.h?
> 

Seems to be based on the maximum amount of usable memory.  If you define
PAE then it's set to 240.

For AMD64 it's set to 32.

> Which leads me to two more questions:
> - is it possible to change the NKTP value without recompiling the kernel?  I think there isn't but I'll ask.

No.

> - is it possible to change the NKTP value without editing pmap.h (can I pass a variable into the kernel build process)?
> 

Well, the header files all semm to have "#ifndef NKPT" in them.  Try doing
"NKPT=xxx;export NKPT" before compiling the kernel and see what happens.

---
Gary Jennejohn