Double compare-and-exchange

By: Linus Torvalds (torvalds.delete@this.linux-foundation.org), March 26, 2008 10:50 am
Room: Moderated Discussions
Jamie Lucier (jamie.lucier@gmail.com) on 3/25/08 wrote:
>
>I'm not trolling here, but do you think this preference
>of yours not to work with "loud" machines has in any way
>impacted Linux in scale up large N-way server platforms
>which are as a rule loud?

Heh. It just means that somebody else has to do the actual
measurements.

Back in the early Linux/SMP days I did actually put up
with one particularly loud and obnoxious machine (if I
recall correctly it was a 8-way 200MHz Pentium Pro or
something equally ridiculous by todays standards, but
it might even have been just a four-way), because I really
needed something more than a two-way because some
problems literally need more than two CPU's to show up.

So I'll put up with load machines if there is any real
reason to accept them. But it has to be a valid reason,
not just "loud because it's badly designed".

(Side note: I know I'm not alone in this. I have it on
good authority that loud machines get less attention - or
are thrown at very junior people who can't complain - at
other places too, including MS and inside Intel itself)

> [..] and I also find that in the last couple of years
>there has been some public benchmarks which would suggest
>that Linux can deliver similar scaling as any other OS out
>there.

That's the understatement of the year. I think we probably
scale better than anybody else out there (although I'm odd
and think that scaling down is an equally important part of
it, and also think that "scaling" is not about how many
times faster you get, but about how good performance you
can reach).

>But does your day to system for development and testing
>in any way prevent Linux from not just matching the
>scalability of existing OSes but far exceeding them?

I actually hope it's an industry trend.

Intel people who gave me machines used to think my
preferences for silent machines were odd and unusual (and
I got some specially built enclosures just because their
normal development boxes sucked). But in the last few
years they seem to have been getting the same kind of
feedback from others too.

Or maybe it's just the whole "power matters" thing that
automatically meant that my concerns became common issues.

In other words, I'd like to think that I wasn't holding
anything up, quite the reverse. I was power-conscious long
before the industry was, even if my reasons for being so
may have been different from other peoples ;)

And yes, people who want to work with loud machines can
still do so. I don't care, as long as I don't have to put
up with them personally. That's the beauty of open source...

Linus
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