On 4/19/06, Hugh Fisher <[EMAIL PROTECTED]> wrote: > > Now that shaders have branches it's not guaranteed that > they all execute in lockstep, but there is a very high > probability that all the execution units will need to read > from the same memory location at the same time. Brute > force replication might work better than dynamic scheduling. >
You have a point. Aside from a small possibility for variation in instruction sequence, if one pixel's shader needs the vector multiplier, then they all do, at the same time. But what I was thinking was that if they all needed the vmul unit on one cycle but not on the next, then two of the threads' instructions could be scheduled on one cycle and two on the next. What are the chances that we'll get a long stream of vmuls all in a row with no breaks? In that case, it would definitely be better to have four completely independent functional units. There are definitely some things we would want to do about multiple threads accessing the same (or nearby) memory locations. _______________________________________________ Open-graphics mailing list [email protected] http://lists.duskglow.com/mailman/listinfo/open-graphics List service provided by Duskglow Consulting, LLC (www.duskglow.com)
