David.Comay at Sun.COM wrote: > >> 1. Have you determined that -xO5 generates the best performing code on both > >> SPARC and Intel. The fact that -xO5 is the highest optimization level > >> doesn't > >> always mean it generates the fastest, best performing code. Aggressive > >> inlining > >> can sometimes lead to cache thrashing, which ends up having the exact > >> opposite > >> effect from the one intended. > > > No, I don't think we have tested this really. But I'd like to keep it > > for now and make a decision when we'd had time to test this. > > In addition to the issues that Stefan brought up, higher optimization > levels can also lead to code generation bugs and may cause correctness > issues.
Technically _any_ optimisation level may expose bugs... but AFAIK anything up to -xO4 should be safe with the Sun Studio 11 version used by OS/Net unless you have stuff like weired driver code which doesn't use |volatile| correctly when poking into hardware registers or signal handler code interacting through non-|volatile| stack variables with normal code (and normal applications in SFWNV don't fall into this category (except shells but the authors of that code know about the trouble with signal handlers...)). ---- Bye, Roland -- __ . . __ (o.\ \/ /.o) roland.mainz at nrubsig.org \__\/\/__/ MPEG specialist, C&&JAVA&&Sun&&Unix programmer /O /==\ O\ TEL <currently fluctuating> (;O/ \/ \O;)
