[Virtualacorn-list] VirtualRPC Speed Comparisons...

[David J. Ruck]

David Pitt <pittdj at pittdj.co.uk> wrote:
> Using 32bit Bogomips (UPP) and Dhrystones :-
> 
> Platform            BogoMips   Dhrystones
> Iyonix OS 5.13      593        850340
> A9home OS 4.42      192        675675
> VRPC Vista          422        613120
> VRPC WindowsXP SP3  218        300380 
> Kinetic 300 OS6.06  192        513620

That's what I'd expect to see. Ignoring Bogomips which are a very poor
measure of anything, Dhrystones reflect quite well the performance of the
VRPC JIT in handling pure instruction emulation. Modern x86 manage
somewhere around the A9's level of CPU performance, faster than a
StringARM, but still falling quite a bit short of the Iyonix's XScale.

However, for memory bound operations, such as manipulating large bitmaps,
the emulator can take advantage of PC's much faster memory systems, and
outperform and ARM based machine by a large factor. This is an area I want
to see some more figures from.

For disc I/O the loading of very large files may be a bit slower due to the
vagarities of filing systems and VM, but for most disc accesses the
emulator will be faster, and very much faster on repeated accesses to the
same files, taking advantage of the underlying OS's disc caching, which
native RISC OS does not have.

With real world applications some things are a bit quicker and some a bit
slower on both native and emulator, but fell fairly equivelent overall.
Where the emulator is badly let down is the random freezes caused by
Windows stopping to do something (including inerference from anti-virus
software) which you don't get on native machines. RISC OS may lock you out
for periods of single tasking, but invariably only when you've told it to
do something, so you know why it is doing it. What Windows is up to most of
the time is anyones guess.

Cheers
---Dave

-- 
Email: druck at druck.org.uk
Phone: +44- (0)7974 108301