rcd@ico.isc.com (Dick Dunn) (03/28/90)
> >The Greenhills compilers have always impressed me and I do plainly recall > >that this particular Compaq was running about 2KDhry faster than what > >everyone else was showing. > Anybody have an address or other contact point for GreenHills? Actually, if you just want fast Dhrystones, it's easier than that. I can send you the output of Dhrystone and you can just tweak a couple of lines to get whatever Dhrystone rating you want! If, on the other hand, you're interested in better performance out of your machine, the problem is somewhat harder... Seriously, my point is that the Dhrystone has always been a so-so bench- mark, and as compilers get better, Dhrystone's predictive value gets worse. I have heard comments that Greenhills did some Dhrystone-specific optimi- zations. I can't verify that particular one, but I have seen other compiler folks do Dhrystone-tuning to get good benchmarks so they could sell compilers or machines. These optimizations often don't do any good at all on real problems. You need real benchmarks to measure real performance, and real benchmarks are hard. It would be OK if folks just used Dhrystone for a finger-in-the-wind guess at how fast a machine is...but they don't. -- Dick Dunn rcd@ico.isc.com uucp: {ncar,nbires}!ico!rcd (303)449-2870 ...Relax...don't worry...have a homebrew.