Mailing Lists: Apple Mailing Lists
Image of Mac OS face in stamp
 
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: Mac OS X Java Performance

<email@hidden> wrote:

>I don't think it is reasonable to scale by CPU-clock as the very different
>architechtures means that the amount of work done in a clock cycle varies
>between them.

But that's exactly the point: finding the amount of work done in a
clock-cycle. This at least allows you to make comparisons independent of
clock-rate. Otherwise a 1.2 GHZ Xyzzy will be roughly 20% faster than a
1.0 GHz Xyzzy, and the primary reason for the discrepancy would be
clock-rate, not JVM, OS, memory, bus, etc. In other words, all you'd be
doing is measuring clock-rate.


>I have heard that a 500 MHz PowerPc should do the same as a 1 GHz x86
>processor. Unfortunately, _that_ just makes your point even stronger :)

Context is crucial. A 500 MHz PPC does get more work done in a unit of
time than a 1 GHz x86. When using AltiVec instructions. Lamentably,
running a JVM takes more than just AltiVec instructions.

There may be other situations where that also holds, depending on exactly
which CPUs you're comparing -- not all PowerPC chips are the same, nor are
all x86s. As a general rule, it doesn't hold up and rapidly turns into
condensed granules of Jobsian RDF.

-- GG
_______________________________________________
java-dev mailing list | email@hidden
Help/Unsubscribe/Archives: http://www.lists.apple.com/mailman/listinfo/java-dev
Be sure to read the FAQ http://developer.apple.com/java/faq/ before posting
Do not post admin requests to the list. They will be ignored.


Visit the Apple Store online or at retail locations.
1-800-MY-APPLE

Contact Apple | Terms of Use | Privacy Policy

Copyright © 2007 Apple Inc. All rights reserved.