On Monday 18 May 2009 19:59:14 William Hubbs wrote: > On Mon, May 18, 2009 at 07:39:48PM +0200, Alan McKinnon wrote: > > On Monday 18 May 2009 19:12:22 William Hubbs wrote: > > > Another difference is that, since you are compiling everything from > > > source, with the correct CFLAGS and CXXFLAGS settings in make.conf, you > > > can optimize the binaries you produce to take full advantage of your > > > processor, which you can't do on a binary distro since everything is > > > already compiled for you. > > > > Another word: > > > > That's ricing. > > > > Ok, that's two words. You get the idea. > > Actually, I don't, because I don't know what you mean. I was just > pointing out something about gentoo which I think is different from a > binary distribution. I don't know how much of a difference it makes, > but it is a feature they don't have.
The cases where one really does need to optimize the compiler for your cpu are very rare, and only really apply to old hardware. Back in the day they performed fine, but code available today tends to do more (keeping pace with cpu capability) so you need to tweak things to extract the best performance. If using current packages on current hardware, the benefit is questionable and users are highly unlikely to notice much difference between good old i686 and -O9. With some apps it does make a difference - extensive floating point ops comes to mind - and one should take advantage of those cases. However, looking into the ebuilds of such packages usually reveals that, if the maintainer is any good, those optimizations are already present in the ebuild. Years ago Gentoo had a problem with fanatical moronic users claiming their machines performed a brazillion time faster with -O9 and other such nonsense. This is called "ricing" - a word play on young Japanese males modifying Subarus for "performance" that actually reduces performance. Ever seen a Subaru with a gigantic whale-tail rear spoiler? That's ricing. These Gentoo users seem to have gone away to wherever the current fashion fad is. For a while they infested Ubuntu. $DEITY only knows where they are now, maybe they're using MacOS and annoying Steve Actual benchmarks should that ricing does nothing beneficial for the average ricer. Genuine analysis of Gentoo machines admined by someone who knows how to do it should that the machine can easily have only the features and software on it that the admin say it should have. Like LDAP - not everyone needs it. On a binary distro, if the maintainer supports it you usually get it too whether you like it or not. With Gentoo, USE is your friend. And this is gentoo's greatest strength - the ability to build something much closer to what you really want than is possible with a binary distro. -- alan dot mckinnon at gmail dot com
