[nylug-talk] x86-64 for 1GiB+ programs (especially in VMs) -- WAS: LOWMEM vs. HIGHMEM performance advantage?

[Peter C. Norton]

On Tue, Apr 22, 2008 at 11:15:30AM -0400, Alex Pilosov wrote:
> > Page tables _are_always_ in use!  It's not a 4KiB v. 2MiB or other,
> > related issue.  The problem is when you start killing the memory model
> > with excessive ones, because of the limitations of the memory model.
> > There is no "magic amount of memory/memory usage," and I have
> > re-emphasized my statement was 'in my experience' and, furthermore,
> > stated a 'benchmark' was required for the user's application.
> @*(#*&(@#$&*#$&*
> 
> Show me something, anything, that shows that HIGHMEM hurts performance. IN
> ANY WAY. ANYHOW.  (after 2.4.22 kernels). 
> 
> IT DOES NOT. END OF STORY. *(@#*(@#. No need for specific benchmarks for 
> his application. It is ir-#$*(@#$-relevant.

Alex, these are all assertions, from your side and from the
other. This thread  has outlived its usefulness. 

There are too few details about the system experiencing this problem
(BIOS upgraded? Kernels .config? Test booted with mem=2048, etc. not
done), and too much flamage about hand-waving. 

Everyone, please resist doing anything but answering questions from
the OP on this thread. Consider this an admin warning.

Thanks,

-Peter

-- 
The 5 year plan:
In five years we'll make up another plan.
Or just re-use this one.