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Intel's New Compiler Boosts Transmeta's Crusoe

Posted by timothy on from the take-that-archenemy dept.

Bram Stolk writes: "Intel recently released its new C++ compiler for linux. I've been testing it on my TM5600 Crusoe. Ironically, it turns out that Transmeta's arch nemesis, Intel, provides the tools to really unlock Crusoe's full potential on linux." It doesn't support all of gcc's extensions, so Intel's compiler can't compile the Linux kernel yet, but choice is nice.

6 of 272 comments (clear)

  1. next version will do the kernel by grover · · Score: 5, Informative

    ...because this is the first question everyone asks as soon as they find out Intel's compiler works on Linux. ;-)

    I'm not surprised the compiler helped Crusoe. GCC is a remarkable achievement in portability, but architecture-tailored compilers (MSVC, ICC) do better both in terms of code size and speed - like 30% better. But if you're going to PAY for your compiler, it better not be beaten by a free alternative.

    I hope we see distros using icc, and I also hope it spurs further development in GCC.

  2. Re:GCC extensions?? by wmshub · · Score: 5, Informative
    Yes, the kernel uses enormous numbers of GCC extensions. It gets significant performance improvements this way. Perhaps you are willing to give up kernel performance for a portability, but from my experience as an instructor in a Linux device drivers class, you are in the vast minority. A kernel really needs assembly inlines (for example the sti and cli instructions are get inserted pretty frequently in critical code paths), and to do them well you have to use extensions to C.

    There are even some places where GCC extensions make the code easier to maintain. For example, the way that device driver entry points are defined is much cleaner (using the "structure member : value" structure initialization syntax) and less error prone than using standard C.

    Yes, it might have been helpful a few times to have been able to compile Linux on a non-GCC compiler, but not very often. And GCC runs almost everywhere, so limiting yourself to GCC doesn't limit the architectures you can port to. It really does seem that in this case the benefits outweigh the losses.

  3. Wrong... by Carnage4Life · · Score: 5, Informative

    What if, besides caruso, Intel's compiler is actually a BETTER compiler than gcc on intel hardware? Then were stuck using gcc for compiling the kernel when something better is or might be some day available. . Locking the kernel to a compiler is a BAD THING[tm].

    The Linux kernel is not only available on Intel chips. It is available on ARMs, DEC Alphas, SUN Sparcs, M68000 machines (like Atari and
    & Amiga), MIPS and PowerPC, as well as IBM mainframes.

    Which makes more sense? Targetting a cross plartform compiler like gcc are targetting individiual compilers for each platform Linux runs on?

  4. Re:Kernel by be-fan · · Score: 4, Informative

    Because Linux is a real project and not some theoretical programming plaything. Kernels have all sorts of weird problems to deal with (passing parameters via registers, inline ASM, structure packing, alignment, etc) that normal application code doesn't have to bother with.

    --
    A deep unwavering belief is a sure sign you're missing something...
  5. Results not surprising by jgarzik · · Score: 5, Informative
    These are not surprising results. Even the gcc developers will admit that many general, not-architecture-specific optimizations done by commercial compilers are not performed in gcc. Most new CPUs, not just Intel CPUs, can benefit from a smarter compiler to take advantage of features like data prefetching, instruction bundling and pipelining, profile-based (feedback-based) optimization, data and control speculation, and much more.

    The gcc "open projects" page gives people a good idea of what remains to be done on gcc. The minutes of the IA-64 GCC summit are especially interesting and informative, because it gives a good idea of the current state of GCC and also what GCC needs to be a competitive compiler in the future.

    Bottom line: Do not be surprised when commercial compilers beat gcc performance. It's catching up, but it's still got a long way to go.

    GCC Home Page

  6. Re:What about gcc 3.0 ? by the+Atomic+Rabbit · · Score: 4, Informative

    From what I gather reading the mailing lists, GCC 3.0 was a features release, and 3.0.x were bugfix releases. There is generally very little performance benefit over 2.9.x (and the occasional performance regression.)

    GCC 3.1 will focus on optimization, building on the new infrastructure implemented with 3.0. If you're brave enough, you can pull from CVS and try it out for yourself.