Some news, and a question to consider. I managed to speed up the ATI chain generation by somewhere close to 30%. Currently a single 5850 card can calculate ~650 chains pr second, meaning my dual card setup can complete a table in less than 2.5 days.
I did this by unrolling my loop a little, and rather than shifting the output, I use indexed writes to cached memory. Since ALU clauses are run in parallel with memory fetches in the GPU threading engine this is almost a pure gain. I still have some more tricks up my sleeves, but first a question for Karsten or whoever would like to do the maths: I am thinking about "merge free table generations", and the procedure goes like this: Start with 270M points, and calculate the first round only and write to disk. Then read that output, and bucket sort the DP1s, eliminating any merges. For non merges, calculate the second round and write to disk. Repeat this for every 32 rounds, keeping fewer and fewer chains, and you will have produced a table containing only merges from the 32nd round. Clearly this is faster, as disk access is much quicker than calculating the rounds, but the real question is how much work can you eliminate this way ? What speedup will you get ? f _______________________________________________ A51 mailing list [email protected] http://lists.lists.reflextor.com/cgi-bin/mailman/listinfo/a51
