On Tue, 2010-08-24 at 14:40 +0200, Frank A. Stevenson wrote: > I finally figured out why 2 of my disks were operating at "half speed". > > I will try to rewire the disks, but I might have to get an extra > controller to fix this issue. >
ATIs southbridge chipset may or may not be to blame for the problem. I think it is caused by the presence of a SATA port multiplier on the motherboard. So in the end I had to get another controller. I ended up buying a very cheap St Lab A-341 PCI-E 2 channel controller, it uses a Sil 3132, supports NCQ and just works with Linux. Using this controller I now get 34 seconds lookup times on 4 disks. But the last 6 seconds or so are pure GPU latency (waiting for the last disk access to be verified as a false hit) To get around this problem I have start looking at lowering the latency of the GPU kernel, but this is a bit of work. But it may be worth it since it will mean a < 10% speedup for single searches. The other option is to run overlapping searches to eliminate pauses in hard disk reading. But ideally we should then need a way to terminate an ongoing search in order free up work queue when the first search in a series is a positive hit. Frank _______________________________________________ A51 mailing list [email protected] http://lists.lists.reflextor.com/cgi-bin/mailman/listinfo/a51
