mr@racal-itd.co.uk (05/30/90)
I'm running some bit crunching code which needs to run as fast as I can make it. Its been recoded in SPARC assembler (yeuch). Running it on a 4/60 (SunOS 4.1c) I find that different runs on the same data can give a ~15% difference in real (wall) time, but not usually a time in between. The machine is otherwise idle. In order to minimise edge effects my test program reads the data in to memory and then runs the algorithm 5 times. The 4/60 is not paging. I don't believe that any other process on the machine is affecting it. I have a suspicion that I am hitting an artifact of the cache system. The code is a few thousand words and the data is typically 100 kbytes. Any comments or suggestions welcomed. Please feel free to ask questions. Regards, Martin Reed, Racal Imaging Systems Ltd uucp: mr@ritd.co.uk, uunet!ukc!ritd!mr Global String: +44 256 469943 Fax: +44 256 471492 Paper: Rankine Road, Basingstoke, Hants, England, RG24 0NW