On Mon, Nov 05, 2007 at 12:49:46PM -0800, Sriram Natarajan wrote: > Well, there seems to be a bit of disconnect here. Sun Studio Compiler > folks consistently recommend us to use '-fast' compiler option but at > the same time folks reviewing our integration within SXDE give a > consistent 'NO' to this option. I am not sure, what is the right > direction here. It will be very unfortunate and confusing for folks > using SXDE or Indiana if components from Cool Stack can significantly > out perform.
Long ago, the people doing Cool Stack came to the SFW C-team and asked us a bunch of questions about compiler flags. It was clear that they'd been talking with the Studio folks and wanted "the best possible performance." If I remember correctly, our advice was to choose the best flags that don't hinder correctness or portability and use the same compiler as the rest of SFW uses. That's still good advice. That Cool Stack is off doing something else is disappointing but irrelevant. This really comes down to competing interests. On the one side are HPC users and compiler partisans. They know everything about the target hardware and the software they've written and they want performance at any cost. -fast is perfect for them. On the other side are people distributing general-purpose software and the people running data centres that rely on that software. They care about performance, but because they use a variety of hardware and are accepting software they don't understand fully, they are willing to sacrifice a little performance to ensure correctness. -fast is not appropriate for them. If you really think -fast is what you want, why not read the docs to understand all the flags -fast expands to and exactly which are certain to be safe, and use those in your makefiles instead? -- Keith M Wesolowski "Sir, we're surrounded!" FishWorks "Excellent; we can attack in any direction!"
