[gentoo-amd64] Re: [OT] AGPART [SOLVED]

[Duncan]

Daniel Iliev <danny@××××××××.com> posted
20070505075815.DE6FA92266@×××××××××××××.com, excerpted below, on  Sat, 05
May 2007 10:58:13 +0300:

> Duncan, thanks for your most detailed answer. Now I know an additional
> thing that should be done when compiling a kernel for systems with >3.5G
> RAM. Unfortunately I've got no such "problem" ;-) and I'm happy with my
> 1G of RAM. It gets rarely used at 100%. Actually only in situations like
> compilation of updated packages + web surfing in the same time. Beryl
> and Firefox are my biggest resident memory hogs.

Well, 4 gigs RAM or so opens some real nice possibilities, particularly 
on Gentoo.  Among other things, one can point PORTAGE_TMPDIR at a tmpfs, 
and compile most things entirely in memory! =8^)  Of course, not only 
does that speed up compiles significantly, but it decreases I/O 
contention, so the rest of your system, especially read/write to disk, 
remains much more responsive during compiles.  Combine that with 
MAKEOPTS="-j1" on a dual-core or dual CPU, and/or PORTAGE_NICENESS=19, 
and compiles don't bother you at all.

However, for normal use, 2 gigs seems a very good balance, as at least 
here. I'll run half a gig to a gig of app memory, leaving a gig of memory 
for cache.  With a gig of memory, the system still works very well, but 
most of cache is thrown away during memory intensive tasks (like some 
compiles, or working with large image files or the like), and I really /
hate/ to see that happen, when I know I'll only have to read that data 
back in from disk later.  Two gigs is enough to use a gig of app memory 
at times and still have a gig of cache that's doesn't have to be thrown 
out on top of that, so it's a nice sweet spot.

Actually, here, I have 8 gigs.  That's a bit overkill.  I'd probably 
stick with four if I were doing it over, as over four gigs remains 
entirely empty, most of the time, not even used for cache.  Still, I have 
dual Opterons now, and was buying with dual-cores in mind.  8 gig of 
memory should still be plenty with dual dual-cores, even out three more 
years, which is when I expect to start getting serious about upgrading my 
entire platform once again.  So the 8 gig was future-proofing, and I 
certainly accomplished that.  Still, it's the first time I can honestly 
say I've had so much memory I rarely fill it up, even with cache, and 
it's nice to have had the experience at least /once/ in my life. =8^)

-- 
Duncan - List replies preferred.   No HTML msgs.
"Every nonfree program has a lord, a master --
and if you use the program, he is your master."  Richard Stallman

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