Path: utzoo!attcan!uunet!snorkelwacker!usc!zaphod.mps.ohio-state.edu!uakari.primate.wisc.edu!ames!amelia!wilbur.nas.nasa.gov!ciotti
From: ciotti@wilbur.nas.nasa.gov (Robert B. Ciotti)
Newsgroups: comp.sys.super
Subject: Re: I/O subsystems (was Re: Supercomputer ROI)
Message-ID: <6397@amelia.nas.nasa.gov>
Date: 30 May 90 18:55:52 GMT
References: <359@garth.UUCP> <6374@amelia.nas.nasa.gov> <6543@vax1.acs.udel.EDU>
Sender: news@amelia.nas.nasa.gov
Reply-To: ciotti@wilbur.nas.nasa.gov (Robert B. Ciotti)
Organization: NASA Ames Research Center, Moffett Field, CA
Lines: 41

In article <6543@vax1.acs.udel.EDU> mccalpin@vax1.udel.edu (John D Mccalpin) writes:
>In article <6374@amelia.nas.nasa.gov> yamo@wk46.nas.nasa.gov (Michael Yamasaki) writes:
>>In article <359@garth.UUCP> fouts@bozeman.ingr.com (Martin Fouts) writes:
>>>
>>>One of the ways in which cheap workstations got to be cheap was by
>>>neglecting to install I/O hardware.  [...]
>
>>My workstation (a Personal Iris) gets something less than a megabyte/second
>>disk I/O.  Our Cray 2 gets something more than 10 megabytes/second.  You

>Well, I guess I am a bit confused, because 10% of the I/O performance of
>a Cray 2 means that your workstation is relatively imbalanced *toward* I/O
>performance, rather than away from it!
>
>My Personal Iris runs my 64-bit codes at about 1-2 MFLOPS, which makes it
>about 1% of a Y/MP.  

A single processor that is, average workload performance puts it at .1%

>The I/O numbers that I have seen are on the order of
>1 MB/s, while the Cray numbers are on the order of 10 MB/s to disk -- so I
>get about 10% of the Y/MP.

single process/single stream rates again that is, aggregate rotating
media performance comes out at .5%, and including the SSD, .0714%

For our Y-MP,
The I/O performance for *Standard* FORTRAN I/O I have measured to exceed 1.2 
 gigabytes per second from a single process/single I/O stream to a 
 SSD cached filesystem (yes its memory, but thats what it for, 2 gigabytes).

multiple process/multiple stream I/O rates to disk have been benched exceeding
200 megabytes per second.

Big killer micro configurations are going to have to compete with the aggregate
rates as well as the single thread rates. (parallel)Flops just ain't good 
enough, your results have to go somewhere , If you can put a big SSD type 
memory to use for I/O, your still going to have to get it there somehow and 
in a standard way.

Bob