Re: Can a task on each of 2 processors share 7 GB of physical m emory
Re: Can a task on each of 2 processors share 7 GB of physical m emory
- Subject: Re: Can a task on each of 2 processors share 7 GB of physical m emory
- From: Shawn Erickson <email@hidden>
- Date: Thu, 13 Nov 2003 14:53:48 -0800
On Nov 13, 2003, at 8:58 AM, Miller, Larry wrote:
Quinn,
By wired, I mean the data that I put in the memory remains at a fixed
place
in physical memory - it is not paged out. This would probably be
equivalent
to a fixed mapping from VM to physical memory.
Does it need to be fixed in a physical address location? or just
prevented from being paged out?
I heard that OS-X Panther was in some ways a 64-bit OS. In other
words, I
thought tasks could execute 64-bit addressing load and store machine
instructions. Maybe I am mistaken.
Panther (and 10.2.7/8) have some level of support for 64b physical
addressing but it is not exposed at the process level yet. Aspects of
this ability is exposed in the kernel for dealing with taking 64b
physical addresses and mapping things such that you can DMA using 32b
addresses for PCI, etc.
The VM sub-system supports the use of 64b physical addresses (to use
the 8GB available in G5s for example) for mapping to process but
processes are still limited to 32b.
Also, I maybe mistakenly thought that you could compile a C/C++
program in a
way such that you could have 64-bit pointers that are dereferenced.
You could get the compiler to do that but 10.3 (or 10.2.7/8) do not
support 64b addressing for processes nor does any of user-land OS
frameworks/libraries/APIs support 64b addresses.
If these things are not available, does anyone one have an idea of
when they
will become available in the future?
Any such future information is under NDA (just about as it always is
for Apple). If you have a strong business need to know this information
consider filing a DTS incident with Apple
(
http://developer.apple.com/products/techsupport/index.html). By doing
so you may get the information you need (under NDA of course). You will
not get such information on this email list.
I believe on the "drivers" list you may have gotten a suggestion on a
possible short term solution (not reviewed the solution yet myself).
-Shawn
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