IBM Active Memory Expansion = compression in the idle loop.

[Julian H. Stacey]

Hi arch at freebsd.org
cc Wolfgang Stief <stief at guug.de> FYI

Just mentioning this for general interest:

At an IBM presentation to SAGE (Sys Admin Guild) in Munich yesterday
2013-03-12, IBM mentioned "Active Memory Expansion' Which is memory
compression using spare CPU cycles,

IBM tend to have more spare CPU cycles as sometimes software 
is only licenced for so many CPUs, & other CPUs are idling.

Interesting idea, though presumably less useful for FreeBSD (& Linux etc)
where we dont generaly have those licensed binary per CPU issues, so perhaps
less spare unused CPU cycles.

http://ixquick.com (search engine) found this:
https://www.ibm.com/developerworks/wikis/display/WikiPtype/IBM+Active+Memory+Expansion

The projector slides were some German, some American, some PDFs of
the evening's 3 presentations will be linked here in a couple of
days I expect.
	http://www.guug.de/lokal/muenchen/index.html

I didnt ask (but wondered) what sort of loads would have lots of
flabby data that could be easily cheaply compressed. IBM were
obviously focused on business databases (I wonder if they still
ahve fixed length records ?) Presumably less interesting to compress
RAM data if a CPU is working on eg geographic topography data or
some such ?

I also didnt ask if it was patented (in case any think
"great idea" & rush off to code :-)

Apparently IBM's Linux dev drivers are all public source, not binary
only, (but presumably FSF licence), but I think this IBM Active
Memory Expansion (AME) is only (as per URL above) for * HMC:
V7R7.1.0.0 * eFW: 7.1 * AIX: 6.1 TL4 SP2 & not for Linux, so probably
there's no public source to browse.

Anyway, seemed an odd new idea to me.

Cheers,
Julian
-- 
Julian Stacey, BSD Unix Linux C Sys Eng Consultant, Munich http://berklix.com
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