Date: Tue, 09 Jul 2002 15:51:22 -0700 From: Terry Lambert <tlambert2@mindspring.com> To: Idar Tollefsen <Idar.Tollefsen@baerum.kommune.no> Cc: freebsd-alpha@freebsd.org Subject: Re: Compaq-CC, the next steps.... Message-ID: <3D2B68EA.7FE85FC7@mindspring.com> References: <sd2ad261.043@mail.baerum.kommune.no>
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Idar Tollefsen wrote: > >> FreeBSD and Linux don't use the same ELF format, do they? > > Yes. > = > OK. Thanks for clearing that up. As someone else pointed out, the compiler in question cranks out assembly language, so as long as the GNU assembler supports its output, it doesn't really care about ELF format. That's how the compiler port is working in this case, so it doesn't know from ELF. But I can, and do, use Linux binary ELF code from third party vendors in my FreeBSD kernel (such modules are, by their nature, not GPL'ed). As long as there are no external references to Linux-specific code (e.g. system call traps), it doesn't matter. One of the things people discussed recently was whether it was the compiler, or the Compaq math library itself, which was the cause of certain applications (e.g. the "Blade" encoder) going much faster. To test their theory, they linked FreeBSD programs against the Compaq provided math library, a binary in ELF format. > >> =CCf that's the case, is there really a speed increase to be > >> gained? And even if it is, do we really want the FreeBSD ports > >> collection to prefer building Linux/Alpha binaries over native > >> binaries on the Alpha? > = > > You seem to believe that the Linux compatability module is an > > emulator. It's not. It's an ABI. There are no performance > > penalties for running Linux binaries (other than those imposed > > by use of the Linux system interfaces by virtue of their design). > = > Well, yes, I suppose I was under the impression that it was > an emulator. Although I have seen references to the contrary > before, this is the first time someone has actually explained > the workings of it. Thank you. No problem. A lot of people make this mistake, because FreeBSD, very early on, made the mistake of calling it an "emulator", when it wasn't an emulator (I guess "Linuxulator" was just too "cute" to pass up). It turns out that for certain applications, Linux binaries actually ran faster on FreeBSD than they did on Linux, for a long time. I haven't seen recent Linux compared with recent FreeBSD, though. -- Terry To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-alpha" in the body of the message
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