Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!swrinde!elroy.jpl.nasa.gov!ncar!gatech!udel!nigel.ee.udel.edu!mccalpin From: mccalpin@perelandra.cms.udel.edu (John D. McCalpin) Newsgroups: comp.benchmarks Subject: Re: A question about flat out Snake speed. Message-ID: Date: 9 Apr 91 23:08:43 GMT References: <7834@idunno.Princeton.EDU> <45780004@hpcupt3.cup.hp.com> Sender: usenet@ee.udel.edu Organization: College of Marine Studies, U. Del. Lines: 37 Nntp-Posting-Host: perelandra.cms.udel.edu In-reply-to: daryl@hpcupt3.cup.hp.com's message of 8 Apr 91 21:12:21 GMT >>>>> On 8 Apr 91 21:12:21 GMT, daryl@hpcupt3.cup.hp.com (Daryl Odnert) said: Daryl> John McCalpin writes: > The HP has a 32-bit memory bus capable of 1 word/clock transfer rates, > so the "Streaming MFLOPS" for these machines is: > HP/9000 Models: > 720 = 200/24 = 8.3 MFLOPS > 730 = 264/24 = 11.0 MFLOPS > Daryl> John's data on the Snakes machine is incorrect. The HP9000 Daryl> models 720 and 730 have a 64-bit memory bus and are capable of Daryl> 2 word/clock transfer rates. Thus, the correct "Streaming Daryl> MFLOPS" for these machines are: Daryl> HP/9000 Models: Daryl> 720 = 400/24 = 16.7 MFLOPS Daryl> 730 = 528/24 = 22.0 MFLOPS ^^^ I think we have a little misunderstanding here. Daryl is claiming the peak transfer rate from cache to fpu, while I am concerned about the sustained transfer rate from main memory through the cache to the fpu. Ths document that I have in my hands right now (5091-0977E), is very specific: for the 50 MHz machines it claims 400 MB/sec to cache and 200 MB/sec to main memory for the duration of a 64-byte transfer. For the 66 MHz machines, the numbers are (presumably) 528 MB/s and 264 MB/s, respectively. The *sustained* transfer rate will be less than the peak rate, but the peak rate is close enough for my purposes right now. I am interested in seeing the speed for long DAXPY's, though.... -- John D. McCalpin mccalpin@perelandra.cms.udel.edu Assistant Professor mccalpin@brahms.udel.edu College of Marine Studies, U. Del. J.MCCALPIN/OMNET