Re: Scaling noise

[Larry McVoy <lm@bitmover.com>]

On Thu, Sep 04, 2003 at 04:21:16AM +0200, Daniel Phillips wrote:
> On Thursday 04 September 2003 02:49, Larry McVoy wrote:
> > It's much better to have a bunch of OS's and pull
> > them together than have one and try and pry it apart.
> 
> This is bogus.  The numbers clearly don't work if the ccCluster is made of 
> uniprocessors, so obviously the SMP locking has to be implemented anyway, to 
> get each node up to the size just below the supposed knee in the scaling 
> curve.  This eliminates the argument about saving complexity and/or work.

If you thought before you spoke you'd realize how wrong you are.  How many
locks are there in the IRIX/Solaris/Linux I/O path?  How many are needed for
2-4 way scaling?  

Here's the litmus test: list all the locks in the kernel and the locking
hierarchy.  If you, a self claimed genius, can't do it, how can the rest
of us mortals possibly do it?  Quick.  You have 30 seconds, I want a list.
A complete list with the locking hierarchy, no silly awk scripts.  You have
to show which locks can deadlock, from memory.

No list?  Cool, you just proved my point.
-- 
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Larry McVoy              lm at bitmover.com          http://www.bitmover.com/lm