Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!csd4.milw.wisc.edu!bionet!apple!oliveb!sun!chiba!khb From: khb@chiba.Sun.COM (chiba) Newsgroups: comp.arch Subject: Re: Workstations for Lisp Message-ID: <109577@sun.Eng.Sun.COM> Date: 12 Jun 89 21:34:35 GMT References: <486@unipas.fmi.uni-passau.de> <5187@pt.cs.cmu.edu> Sender: news@sun.Eng.Sun.COM Reply-To: khb@sun.UUCP (chiba) Organization: Sun Microsystems, Mountain View Lines: 59 In article dpm@cs.cmu.edu (David Maynard) writes: >ram@wb1.cs.cmu.edu (Rob MacLachlan) writes: >> -- How fast are the disks? Even with lots of memory you will page. > >I don't have direct experience, but recent Sun-Spots (comp.sys.sun) >articles have indicated that the SparcStation is significantly better >at disk I/O than the DECStation 3100. (Gee, could that DMA be paying >off?) > >However, these same articles indicate that the 3100 can be >significantly better for number crunching. I suspect that part of the >difference here is the "quality" of the math libraries. It seems to >take more work to make a Sun run math codes faster. I'm sure the 3100 >does have a raw speed advantage, I'm just not sure it is as great as >some people have reported. Math performance is partially due to design choices in the libraries. One of the key questions (for C) is which standard ... ANSI, SVID, K&R, Posix ... all require slightly different answers to certain cases. Sun's arithmetic group is (perhaps) too concerned with getting the correct answer ... seymour has proved that folks prefer fast to accurate :> > >I believe that more AI software is currently available for the Suns. >Sun has had longer to build an AI base. It is likely that DEC will >try to close this gap though. When there is a DEC sponsored LISP, we can try to determine real performance figures. I am not very AI oriented, but in my limited AI experience IO dominates in most "real" systems (as pointed out above) so I expect the SS330 to perform better on some reasonable set of application sized codes. After IO, the next performance "feature" of AI codes is probably memory subsystem speed. The current MIPS vs. SPARC implementation key difference is cycles for ld/sto ... MIPS is faster; but this results in many stalls on the 3100 (vs. say, the MIPS M2000 with its 4-deep buffered write thru cache) ... the SS330 has enough buffering that stores tend not to lock up ... as best I can remember, the DS3100 has write thru, no buffering ... so loads should be faster, stores slower. After those, the issues of tagged arithmetic, and register windows vs. shared pool probably kick in. My experience is that IO vastly dominates these second order effects, on "real AI applications". > --- > These are my opinions. I haven't asked CMU what our official opinion is. ditto. I haven't even asked sun what our opinon is. Keith H. Bierman |*My thoughts are my own. Only my work belongs to Sun* It's Not My Fault | Marketing Technical Specialist ! kbierman@sun.com I Voted for Bill & | Languages and Performance Tools. Opus (* strange as it may seem, I do more engineering now *)