Messages in this thread |  | | Date | Fri, 30 Nov 2001 17:15:10 -0800 | From | Larry McVoy <> | Subject | Re: Linux/Pro [was Re: Coding style - a non-issue] |
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On Fri, Nov 30, 2001 at 05:13:38PM -0800, Davide Libenzi wrote: > On Fri, 30 Nov 2001, Larry McVoy wrote: > Wait a minute. > Wasn't it you that were screaming against Sun, leaving their team because > their SMP decisions about scaling sucked, because their OS was bloated > like hell with sync spinlocks, saying that they tried to make it scale but > they failed miserably ?
Yup, that's me, guilty on all charges.
> What is changed now to make Solaris, a fairly vanishing OS, to be the > reference OS/devmodel for every kernel developer ?
It's not. I never said that we should solve the same problems the same way that Sun did, go back and read the posting.
> Wasn't it you that were saying that Linux will never scale with more than > 2 CPUs ?
No, that wasn't me. I said it shouldn't scale beyond 4 cpus. I'd be pretty lame if I said it couldn't scale with more than 2. Should != could.
> Because you know that adding fine grained spinlocks will make the OS > complex to maintain and bloated ... like it was Solaris before you > suddendly changed your mind.
Sorry it came out like that, I haven't changed my mind one bit.
> <YOUR QUOTE> > > Then people want more performance. So they thread some more and now > > the locks aren't 1:1 to the objects. What a lock covers starts to > > become fuzzy. Thinks break down quickly after this because what > > happens is that it becomes unclear if you are covered or not and > > it's too much work to figure it out, so each time a thing is added > > to the kernel, it comes with a lock. Before long, your 10 or 20 > > locks are 3000 or more like what Solaris has. This is really bad, > > it hurts performance in far reaching ways and it is impossible to > > undo. > </YOUR QUOTE> > > I kindly agree with this, just curious to understand which kind of amazing > architectural solution Solaris took to be a reference for SMP > development/scaling.
OK, so you got the wrong message. I do _not_ like the approach Sun took, it's a minor miracle that they are able to make Solaris work as well as it works given the design decisions they made.
What I do like is Sun's engineering culture. They work hard, they don't back away from the corner cases, they have high standards. All of which and more are, in my opinion, a requirement to try and solve the problems the way they solved them.
So the problem I've been stewing on is how you go about scaling the OS in a way that doesn't require all those hot shot sun engineers to make it work and maintain it. -- --- Larry McVoy lm at bitmover.com http://www.bitmover.com/lm - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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