Drobe :: The archives
About Drobe | Contact | RSS | Twitter | Tech docs | Downloads | BBC Micro

Confirm comment report request

Oh dear. I really should know better than to get into a benchmark battle, but...

The Trackman2 results intrigued me, so I had a quick look into it. Taking the program as it is, the top-level fractal renders in 0.16 seconds on my Risc PC and 0.42 seconds on my Iyonix. However, this program is unusual in that it does all its calculations in screen memory, constantly reading and writing screen memory bytes, which is not a sensible thing to do on an Iyonix since the screen memory is the other side of the PCI bus, and the graphics card is not optimised for screen memory reads.

I then updated the code to plot into a buffer in main RAM and only copy the results to the screen when it had finished. Result - the top-level fractal now takes 0.06 seconds to plot, and generally the plotting times now seem to be 2.5ish times faster than the Risc PC, which is what you'd expect given the difference in clock speeds.

What does this tell us? 1) Benchmarks will tell you anything you want them to. 2) A little time spent optimising (less than one hour) can yield large benefits (a 700% speed increase in this case). 3) Er, that's it.


P.S. Trackman2 is not 32bit safe. It contains three LDM Rx,{...,PC}^ instructions. I fixed these too.

 is a RISC OS Userjbyrne on 3/3/03 11:27PM
[ Reply | Permalink | Report ]

Click on the button below to confirm you wish to flag up this comment to the website's administrators. Abuse of this service will be frowned upon and it should only be used to notify us of comments that are extremely distasteful, indecent or otherwise unlawful. If you disagree with an opinion expressed or fact stated in a comment, please take part in the debate rather than expect it to be removed.

Return to the drobe.co.uk front page


Reporting user / IP: /
Comment GID: 2496
Timestamp: Wed, 26 Jun 2019 10:00:38 +0000

Search the archives

Today's featured article

  • Select preview
    Every feature in Select 1 covered, what's in, what's out, what's it look like and what do we think of it?
     9 comments, latest by diomus on 15/3/03 1:10AM. Published: 31 Oct 2001

  • Random article

  • Omega MIDI, ethernet progress
    What's next on the to-do list? [Updated]
     64 comments, latest by epistaxsis@work on 21/03/04 5:14PM. Published: 15 Mar 2004

  • Useful links

    News and media:

    Top developers:
    RISCOS LtdRISC OS OpenMW SoftwareR-CompAdvantage SixVirtualAcorn

    CJE MicrosAPDLCastlea4X-AmpleLiquid SiliconWebmonster


    RISCOS.org.ukRISCOS.orgRISCOS.infoFilebaseChris Why's Acorn/RISC OS collectionNetSurf

    Non-RISC OS:
    The RegisterThe InquirerApple InsiderBBC NewsSky NewsGoogle Newsxkcddiodesign

    © 1999-2009 The Drobe Team. Some rights reserved, click here for more information
    Powered by MiniDrobeCMS, based on J4U | Statistics
    "..your knowledge seems to be below par"
    Page generated in 0.1163 seconds.