[CentOS] [OT] Memory Models and Multi/Virtual-Cores -- WAS: 4.0 -> 4.1 update failing

[Bryan J. Smith]

On Fri, 2005-06-24 at 20:16 -0400, Peter Arremann wrote:
> Ok - so the PAE36 mechanism is the same, the 36bit addresses are the same just 
> the address ranges that are reserved for special use are different? 

Ugh, sigh, you're thinking like a programmer.  ;->  You have to separate
the logical (programmer) from the physical (engineer) concepts.

> Sorry meant beyond 32bit address space / 4GB. 

Right, I understood that.
I was just wondering if you meant beyond 36-bit/64GiB as well?
Because EV6 is 40-bit/1TiB.

> That would require an additional level of page translation though or a really 
> substential redesign - so its in my opinion unlikely that they do...

Again, thinking like a programmer.  ;->

The Athlon was _already_ designed for 40-bit EV6 _physically_ and
eventual "Long Mode" programmatically.  The TLB in the Athlon is _not_
designed for GTL, but EV6.  It only works like a GTL when so
commanded.  ;->

> GTL (P5) yes - but that doesn't have PAE36 either... But we're talking PAE 
> here - so GTL+ aera...

I meant GTL and all derivatives ... GTL+, AGTL+, etc...

> The address pins are even labeled up to A35 Download any of the PPro and
> newer spec sheets (except mobile cpus that don't support PAE). The
> Pentium II 300Mhz Specs is a good example. Quote from page 75: "The
> Address signals define a 2^36-byte physical memory address space." 
> document id 24365702.pdf

Of course!  Because if it didn't, it wouldn't be able to page in beyond
4GiB.  @-ppp  Yes, but the TLB compatibility and other issues are
involved, things that GTL and all derivatives _never_ addressed.

In a nutshell, Intel PAE36 processors on even AGTL+ are _incapable_ of
the combination of both _physical_ and _logical_ addressing to do
anything but paging above 4GiB.  That's my point.

AMD solved the problem by using EV6, which is _nothing_ like GTL-based
busses.  It goes far deeper than you realize.


-- 
Bryan J. Smith                                     b.j.smith at ieee.org 
--------------------------------------------------------------------- 
It is mathematically impossible for someone who makes more than you
to be anything but richer than you.  Any tax rate that penalizes them
will also penalize you similarly (to those below you, and then below
them).  Linear algebra, let alone differential calculus or even ele-
mentary concepts of limits, is mutually exclusive with US journalism.
So forget even attempting to explain how tax cuts work.  ;->