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From James Duncan Davidson <james.david...@eng.sun.com>
Subject Re: [spinnaker] Announce
Date Mon, 10 Jul 2000 21:32:47 GMT
on 7/10/00 1:44 PM, Eric Hodges at harmony2@swbell.net wrote:

> It's as if Sun thought we wouldn't use Java for the first 5 years.  Now they
> want a do-over.  Sun can't expect the world to re-write all code for each
> new release of the VM.  One of the selling points of Java is that code won't
> have to be constantly re-written.

What you are asking for is that Sun would have kept Java inside for another
5 years to make it perfect. That would have been the right answer.

> Why can't HotSpot figure out that it's slowing down execution and put itself
> into -classic mode for specific classes?

That's what it's doing.. Running the code it can't optimize interpreted,
which is about as -classic as you can get.

Note -- the code doesn't slow down, it just doesn't benifit.

Generalizations from the data I've seen:

Xerces beats Crimson by a wide margin on 1.1
Xerces and Crimson are running together (+/-, sometimes one on top,
sometimes the other, but no clear winnder) on 1.3.

SO, in general terms -- Xerces isn't slowing down and taking a hit from the
Hotspot, but it ain't gaining either. So, my argument is, when building a
next gen parser, why take the pain of optimizing hellishly if it doesn't buy
you something.

Disclaimer -- there are some interesting cases in Xerces on Hotspot where it
isn't this simple I believe -- but for the purposes of this mail which is
bashing Hotspot on principle, the generalities are good enough.

If you want a way to send some classes to Hotspot, and others to a
traditional JITC, then you are asking for something that's way too complex
and would never ship reasonably bug free.

.duncan


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