On Tue, Oct 22, 2002 at 01:48:35PM -0700, Keith Packard wrote: > > Around 13 o'clock on Oct 22, Ian Romanick wrote: > > > I would recommend an audit then a copy, with the DMA buffer being setup as > > non-cached, write combining memory (like AGP mapped memory). > > Non-cached write combining memory doesn't go through the regular cache > buffers and is significantly slower than cached writes; that's one of the > reasons AGP writes are so slow. Cached writes will force cacheline fills, > which will double the amount of data transfered when doing the copies.
I always thought that was the point of write combining. If you have a 64KB DMA buffer to copy & verify, that will flush a lot of data out of your cache. You especially have to consider that most systems that are likely to have a mach64 based card will be K6-2, Celeron, or G3 based where the caches are very small. -- Smile! http://antwrp.gsfc.nasa.gov/apod/ap990315.html ------------------------------------------------------- This sf.net emial is sponsored by: Influence the future of Java(TM) technology. Join the Java Community Process(SM) (JCP(SM)) program now. http://ad.doubleclick.net/clk;4699841;7576301;v?http://www.sun.com/javavote _______________________________________________ Dri-devel mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/dri-devel
