8 core Mac Pro: Squeak and Croquet

Daniel Lanovaz daniel at precedia.com
Sat Apr 21 18:06:14 UTC 2007


The following are some screenshots of the CPU monitor
(one bar per core) running Squeak and Croquet on the
latest 8 core Mac Pro.

It appears true that Tiger does elicit "core swapping"
behavior, the movement of threads between cores as they
execute. The performance monitor showed Squeak having two
threads, with activity on all 8 cores during normal operation
(except during one of the infinite loop tests), where the
core activity includes, of course, OS threads for window
management, etc.

This test was certainly not scientific.

With Squeak/Croquet riding atop 24 GHz of
64-bit compute power, plus the muscle of an ATI X1900
GPU, the text editing appears to go smoothly. ;-)

The core swapping issue may supposedly be altered in Leopard.
There is probably little performance degradation if the
thread stays on one quad-core chip with the shared L2 cache,
but if the thread moves to another quad-core chip, the
(instruction/data) cache contents need to be reloaded on the
second chip. The second Squeak infinite loop test appears
to show the main Squeak thread moving between two
quad-core chips.

I purchased this machine for 3D animation rendering. My
render software wonderfully takes advantage of all 8
cores, with some impressive performance gains.

Cheers,
Daniel

CPU core usage
==============

Squeak GUI activity:
	http://idisk.mac.com/iphone2007-Public/Squeak/squeak-8-core-01.jpg

	NOTE: Lots of dragging in a text view.

Squeak in an infinite loop:
	http://idisk.mac.com/iphone2007-Public/Squeak/squeak-8-core- 
infinite-02.jpg

	NOTE: Squeak is remaining on 1 core as nothing
	else happens on the system.

Squeak in an infinite loop (switching applications):
	http://idisk.mac.com/iphone2007-Public/Squeak/squeak-8-core- 
infinite-03.jpg

	NOTE: Squeak's infinite loop is moving between cores
	as I switch between applications.

Croquet GUI activity:
	http://idisk.mac.com/iphone2007-Public/Squeak/croquet.1.0.18-8-core.jpg

	NOTE: I was just walking around inside a space.



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