Messages in this thread | | | Date | Fri, 20 Jun 2003 03:08:05 +0100 | From | Nuno Silva <> | Subject | Re: Crusoe's persistent translation on linux? |
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Hi!
Linus Torvalds wrote: > On Fri, 20 Jun 2003, Nuno Silva wrote: > >>This raises a new question. How about a port of Linux to the "VLIW" so >>that we can skip x86 "code morphing" interelly? > > > The native crusoe code - even if it was documented and available - is not > very conductive to general-purpose OS stuff. It has no notion of memory > protection, and there's no MMU for code accesses, so things like kernel > modules simply wouldn't work. > > >>I'm sure that 1GHz would benefit from it. Is it possible, Linus? > > > The translations are usually _better_ than statically compiled native > code (because the whole CPU is designed for speculation, and the static > compilers don't know how to do that), and thus going to native mode is not > necessarily a performance improvement. > > So no, it wouldn't really benefit from it, not to mention that it's not > even an option since Transmeta has never released enough details to do it > anyway. Largely for simple security concerns - if you start giving > interfaces for mucking around with the "microcode", you could do some > really nasty things.
Authoritative answer received! :)
Thanks, Nuno Silva
> > Process startup is slightly slower due to the translation overhead, but > that doesn't matter for the kernel anyway (so a native kernel wouldn't > much help). And we do cache translations in memory, even across > invocations. I suspect the reason large builds are slower are due to slow > memory and/or occasionally overflowing the translation cache. > > Linus > >
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