[Techtalk] more cores, more slows

[John Sturdy]

It shouldn't often be a problem in these days of plentiful RAM, but I
remember seeing early multi-core systems slowing down when increasing
parallelism should have made them faster, and findng that they were
thrashing i.e. the virtual memory system was spending a lot of time
bringing things in from swap space and putting them back there (and
user processes were spending a lot of time suspended waiting for their
pages to come back in), because the working set (the collection of RAM
pages that was needed in at one time) was larger than the available
RAM.

"top" will show you how much RAM and how much swap space is used / free.

I think it's likeliest to be general bloat; it's hard to fill 4GB with
general "stuff".  Last time I got my system thrashing was running
Potlatch, the in-browser editor for OpenStreetMap; I think there was a
memory leak in the flash implementation it used.

I've cleared out one source of bloat by using ratpoison for my window
manager; no decorations and no special effects (neither of which did
anything for me, anyway; I like my whole screen for what I'm working
on).  More RAM for my giant Emacs, as it attempts to evolve into the
Kwisatz Haderach ;-)

__John