Re: [Sheflug] RAID and kernel upgrading.

[Will Newton <nospam [at] misconception.org.uk>]

On Thu, 8 Jun 2000, Alex Hudson wrote:

> Hmmm. John Carmack coded an SMP Quake at one point, and while it was
> probably quite a noddy version he reckoned it gave 10% improvement. Here,

Games, esp. Quake style do not tend to work very well with SMP. There is
no real producer/consumer situation going on that can easily be run
without locking. (e.g. if you have one thread setting up geometry and
another drawing frames, you will need to sync on every frame, which adds a
bunch of locking you could do without and kind of defeats the point)
Input and sound threads are common, but are a tiny fraction of the CPU
usage. Maybe something cool could be done when AI becomes a serious
consideration, but that won't be for a while yet. :)

> we're talking complete io-bound process, in which case there ain't a lot
> you can do without extending the bus arch, etc. With compute-bound
> processes, such as SETI [at] HOME for example, performance is pretty much 100%
> improvement. Personally, though, I don't worry much about extra bogomips
> ;). Certainly, SMP is an interesting system (race conditions, deadlock,
> atomic actions, all real Djikstra stuff ;)

If done properly it should make for a really nippy, responsive
system. Never really been tempted though. I might try one of those dual
celeron boards if I ever win the lottery...

> Look at it. Use it. If it feels faster, all is good. ;)

Either that or you just wish it felt faster cause you spent 700 qiud on
it. :)

> Er, AFAIK devfs is IN. And is the default ... I /think/. Personally, I'm
> in favour of devfs (and people I've mentioned it to seem to like the
> idea), but it doesn't half break, er, *everything*. Plus, I think all the
> names are changing. No more hda1, etc. etc. Ahhhhh......

I don't like it too much TBH. It breaks a LOT of things, so you have to
run devfsd for compatability, so devfs is off on my box and will remain so
till I'm convinced it will actually do something for me.
AFAIK it defaults to off. But then it is a dev. kernel. :)


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