Mike Meyer wrote: > On Fri, 22 Aug 2008 16:49:25 +1200 > Ian Collins <[EMAIL PROTECTED]> wrote: > > >> Mike Meyer wrote: >> >>> On Thu, 21 Aug 2008 18:59:24 +1200 >>> Ian Collins <[EMAIL PROTECTED]> wrote: >>> >>>> Alfred Monticello wrote: >>>> >>>>> The one in /opt/sfw can produce 64bit code but is a 32bit binary. >>>>> >>>> What's wrong with that? >>>> I can't see any reason for wanting a 64 bit compiler binary, unless you >>>> have a file which takes more the 4GB or RAM to compile.. >>>> >>> Is the compiler that built the compiler really so bad that having >>> twice as many general-purpose registers available doesn't make any >>> difference in performance? Or do you simply not care how long it takes >>> to compile things? >>> >> If life was that simple, everything would be built 64 bit on Solaris. >> But it isn't. Some applications run slower, some faster. >> >> What were your benchmark results when you compared 32 and 64 bit >> compiler binaries? >> > > My benchmarks with gcc 4 showed an that 64 bit code ran an average of > about 33% faster than 32 bit code. By code, is that generated code or the compiler its self?
> Once you get beyond simple > benchmarks to real-world applications, you get into interesting > questions like whether you should compare your 32 bit compiler running > on a 64 or a 32 bit kernel (I went with the latter because the systems > I was benchmarking came with compilers that matched the kernel, and > the results matched the rest of the benchmarks). > > I'm surprised there would be any difference. The same application code is running on either kernel. > What benchmarks did you get that show there's really no need for a 64 > bit build of the compiler on OpenSolaris? > > I don't have any, but the Studio developers have commented in the past that they don't see any advantages in building a 64 bit version of their compilers. I guess I should have a try with gcc. My concern was that a 64 bit build would require a larger working memory set for 64 bit pointers, which would result in more cache thrashing than a 32 bit build. Ian _______________________________________________ opensolaris-discuss mailing list [email protected]
