On 3/24/08, Gus Wirth <[EMAIL PROTECTED]> wrote:
> RB W wrote:
> [snip]
> >>  The video can also be a performance killer. The Intel solution uses
> >>  shared memory, which means memory access has to be divided up between
> >>  the graphics and the CPU which leads to contention. You don't specify if
> >>  the AMD solution with the Radeon X1270 has dedicated memory or not. If
> >>  you have dedicated memory for the video, you are going to get better
> >>  performance because you won't have memory contention.
> >>
> >
> > I was thinking that if under XEN everything is networked I could run
> > only one instance using the actual video and then either SSH to the
> > CentOS and other instances and/or VNC/ssh forward the GUI apps as
> > needed. Do I still run into contention in this scenario? In effect I
> > was thinking of running every instance "headless" except for the one I
> > want to "See". I would be comfortable with this because Linux is
> > getting to the point where "pagers" have so many variations you can
> > segregate anything into any number of virtual presentations of local
> > and remote apps.
> [snip]
>
> The competition between video and the CPU for RAM still exists with a
> shared memory arrangement. The video has to refresh the screen at a
> certain rate, usually 60 times a second. For each pixel on the screen
> you are probably reading out 3 bytes for 24 bit color. RAM timing for
> video is a hard limit, so the CPU has to yield for every video access,
> so the CPU suffers. Of course, you might have so much excess processing
> power for what you are doing that you will never notice.
>
> Gus
>

I see what you are saying. Ideally I would like to have really just
one primary desktop with other instances that I can occasionally run
just because I can and I want to test with other distros as desktop
environments. Really exploiting hardware virtualization is something I
want to do to create say 3-5 servers dedicated and optimized for a
particular purpose and trimmed down for security optimization.

I liked the VMWare method even on the current P4 Mobile 1.8GHz w/
768MB RAM but you could really only get one VM running especially if
you ran the Big Fat XP instance. With Linux doing maybe 1-2 instances
at a time. Knoppix live CD was about the best going with VMWare on
this older Laptop (circa 2002).

rbw


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