Re: [NTLK] Einstein Thoughts

From: Paul Guyot (pguyot_at_kallisys.net)
Date: Tue Jan 03 2006 - 14:59:29 PST


Le 3 janv. 06 à 23:23, Paul Guyot a écrit :

> Problem #2 is speed. But it's intervened with memory. I've been
> working tonight on pushing the JIT pages up to the MMU manager to
> avoid the current double lookup situation.

I realize this sounds gibberish.

The MMU does a lookup to translate a virtual address to a physical
address. In the current paged version of Einstein, a second lookup is
performed to get the JIT page. This lookup is actually inefficient
and the entries are often dirtied because many pages (for the jump
tables) are used at several virtual adresses yet I need the virtual
address to do a good code recompilation. I should fix this soon.

Concerning the drawbacks of ARMphetamine and QEMU, you can check the
following documents:
http://armphetamine.sourceforge.net/further.html
http://fabrice.bellard.free.fr/qemu/qemu-tech.html

I just noticed QEMU was updated to support more than just userland
emulation:
http://fabrice.bellard.free.fr/qemu/qemu-doc.html#SEC46
http://lists.gnu.org/archive/html/qemu-devel/2005-12/msg00137.html

But it would still be more work to adapt QEMU to boot NewtonOS than
just optimizing Einstein to get decent performances on a Linux PDA.

Paul

-- 
Ministre ultraplénipotentiaire en disponibilité.
Mobile. Sans baignoire fixe.
http://www.kallisys.com/
http://www-poleia.lip6.fr/~guyot/
-- 
This is the NewtonTalk list - http://www.newtontalk.net/ for all inquiries
Official Newton FAQ: http://www.chuma.org/newton/faq/
WikiWikiNewt for all kinds of articles: http://tools.unna.org/wikiwikinewt/


This archive was generated by hypermail 2.1.5 : Tue Jan 03 2006 - 15:30:05 PST