Keith Packard wrote: > Around 8 o'clock on Aug 21, Peter Kaczowka wrote: > > > If MMX is already being used in Render or has already tried, I'm sorry to > > imply that no one has thought of this before. > > It has been tried with no effect on performance. As I said, current > processors have no optimizations for AGP/PCI read cycles when running in > write-combining mode, each one is a completely separate synchronous > transaction. >
I guess that's true for reads, but my experience is that quadword writes are faster to some PCI devices. That is, a blt from memory to the screen is faster if done with MMX. But that was as/of 2-3 years ago, e.g. on 400 MHz Pentium II machines with PCI bus and our company's own cards e.g. the DOME imaging Md5/PCI card; other cards might handle burst under different conditions. I did not see any improvement writing to other AGP-based cards; DOME doesn't make AGP cards. In any case it wouldn't be a big speedup and there's no substitute for real hardware support. I would be interested in hearing which cards have what kind of hardware Render support if people feel like discussing it. It doesn't relate to what I do now but in a former life I was a 2D graphics type. Keith, if you recall we were both on the XIE working group (me from HP/Apollo). That was a while ago, and after that I never thought I would be using X as part of my job since Windows machines were kicking Unix workstation butt. Who would have thought that X would live on as XFree86? I guess Keith among others did; congratulations on keeping X alive. It's still a far better architecture than Windows and GDI. Sorry to change the subject; I'm not trying to start a separate thread here - but thanks, Keith. Peter Kaczowka > > There is a small speedup available on 16-bit frame buffers by reading > 32-bits at a time, but that will become less important as more people > migrate to 24-bit displays. > > Some people are successfully implementing significant Render acceleration > with hardware; that's clearly the right direction to go. > > Keith Packard XFree86 Core Team HP Cambridge Research Lab _______________________________________________ Render mailing list [EMAIL PROTECTED] http://XFree86.Org/mailman/listinfo/render
