lkml.org 
[lkml]   [2003]   [Jun]   [19]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: Crusoe's persistent translation on linux?
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
>
>




-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2005-03-22 13:36    [W:0.069 / U:0.216 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site