Path: utzoo!attcan!uunet!ogicse!uwm.edu!uwvax!werewolf.cs.wisc.edu!luner From: luner@werewolf.cs.wisc.edu (David L. Luner) Newsgroups: comp.unix.aix Subject: Re: Dhrystone 2.0 timings Summary: Be careful. Things Change. Message-ID: <9856@spool.cs.wisc.edu> Date: 2 Mar 90 18:07:42 GMT References: <1990Feb27.230001.5373@jdyx.UUCP> Sender: news@spool.cs.wisc.edu Organization: IBM Madison Lines: 72 In a previous article shawn@jdyx.UUCP (Shawn Hayes) writes: > Well, this want answer all the questions about how fast the new RS 6000 >machines really are, but here is my attempt to help. Thank you. All we're (and, I suppose, We're all) looking for is a fair evaluation. > I recently got a copy of the Dhrystone program V2.0 and ran it on our >RS 320 machine. The current field releases of AIX V3.1 are preliminary. Furthermore, they are changing daily. I believe the current release is "8943Q". What version we you running on? If you run benchmarks on early releases, be aware that things may change *in either direction*. > The results aren't quite what IBM stated (using V1.0), but > that shouldn't be a big suprise. :> For any number of reasons. First: they even ran the Dhrystone V1.1 on a different release. Second: Dhrystone V2.0 makes things (intentionally) more difficult for the compiler. Third: Read on for caveats w.r.t. "43Q". > I got a value of 11,881.2 dhrystones/sec >using a non-optimized version, and a value of 18,867.9 dhrystones/second >using the optimizer. Averages out to about 11 MIPS which isn't bad. In trying to duplicate the published Dhrystone V1.1 numbers that were published I discovered two things on. For the time being I only assume this is specific to "43Q". Number one, the clock runs at 100Hz. The V1.1 code I was using assumed a 60Hz clock so the numbers looked low. Secondly, there is a problem in the C libraries related to the string handling functions. A bypass (to convince you of the "reasonableness" of the published numbers) is to #include This will in-line the string handling functions. *** I know this is not kosher. Until the C library is fixed in a later release, it will have to do. > > In addition I decided to run another test today and ran 11 copies of the >optimized version at the same time. I got about 18,700 dhrystones/sec on >10 of the copies and about 14,000 on the last copy. Not bad at all. > Assuming that the Dhrystone V2.0 code is like the V1.1 code in this respect, it only looked at user process time, not elapsed clock time. If I am wrong in this, I am impressed because what you stated implies over 187K Dhrystones. > Speaking of benchmarks I have two requests. >First, does anyone know of any good system level benchmarks? IBM has stated that SPEC (for sure) and RAMP-C (I think) numbers will be provided in the forseeable future. Other things you may look at are the MUSBUS and X-benchmarks. > Second, does anyone know how much time an RS 6000/320 will take to do a > context switch?????? We've talked to our SE... Please refer your SE to me. -- David David Luner IBM Madison (608) 273-5243 Disclaimer: #include