Grackle Probe v1.4

What is Grackle Probe?

GrackleProbe is a kernel extension that enables the MPC 106 chip's PCI Store Gathering feature. This could speed up transactions with any PCI device in Grackle based Macs. Grackle Probe is a MacOS X 10.x kernel extension. It is designed to work on MacOS X 10.0.0 and newer. The software was tested on on MacOS X 10.1.5, 10.2.0, 10.2.6, 10.3.0. GrackleProbe is Freeware.

What's new?

Version 1.4 is more reliable on OS X 10.2.0 now due to switching back to the GCC 3.1 compiler.
Changed GrackleProbe so it is suitable for dropping into /Library/StartupItems.
Now comes with grackletool. When GrackleProbe is loaded, executing grackletool will display a bunch of information about the Grackle chip.
Grackletool will display the SDRAM CAS settings the Grackle memoryx controller is configured for. If you have CL 3 RAM, the SDRAM CAS setting is like 3. If you have CL 2 RAM, the CAS setting might or might not be 2. The firmware calculates this really early at startup.
There may or may not be an incompatibility with the ACARD 6820 IDE PCI card. Two people with this card have reported a panic. I'm looking into this.

Who is Grackle Probe for?

Grackle Probe might accelerate certain PCI operations your computer performs. This potentially includes any built-in PCI device (USB, FireWire, video) or any PCI expansion card you have in your machine.

Grackle Probe might accelerate Quartz Extreme further than what is currently being observed by those who have modified the CoreGraphics Configuration.plist file to work with PCI and AGP video cards.

How do I enable Quartz Extreme for AGP & PCI video cards?

As an Administrator, you can edit the Configuration.plist file from Terminal.app:

sudo pico /System/Library/Frameworks/ApplicationServices.framework/Versions/A/Frameworks/CoreGraphics.framework/Versions/A/Resources/Configuration.plist

And delete the line that contains "<string>IOAGPDevice</string>".
'pico' is a text editor. If you want, use 'vi' instead.

What Mac hardware has a Grackle chip in it?

PowerMac G3 (Beige) - Model: Gossamer
PowerMac G3 (Blue & White) - Model: PowerMac1,1
PowerMac G4 (Yikes!) - Model: PowerMac1,2
iMac G3 233MHz -> 333MHz - Model: iMac, iMac,1
PowerBook G3 Series (Wallstreet), Apr 1998
PowerBook G3 Series (Bronze Keyboard, Lombard), Apr 1999
possibly other older G3 and G4 PowerMacs or PowerBooks.

How do I use Grackle Probe?

If you Activate Grackle Probe on demand, you should Deactivate it before Installing Grackle Probe at startup or Uninstalling Grackle Probe.

Activating Grackle Probe on Demand

The current GUI for Grackle Probe consists of a couple of automated command scripts. Follow these steps to use the command scripts:

Uncompress GrackleProbe.sit.
Close all applications and save any work in progress.
Open GrackleProbe/ActivateGrackleProbe.command
PCI Store Gathering should now be enabled on Grackle compatible hosts.

Turning on and off PCI Store Gathering

In Terminal.app:

To enable store gathering: sudo sysctl -w hw.grackle_st_gath_en=1
To disable store gathering: sudo sysctl -w hw.grackle_st_gath_en=0

Deactivating Grackle Probe on Demand

Open GrackleProbe/DeactivateGrackleProbe.command.
PCI Store Gathering should now be enabled on Grackle compatible hosts.

Checking the status of Grackle Probe

Open GrackleProbe/CheckGrackleProbeStatus.command

Installing Grackle Probe - load Grackle Probe at every startup

Open GrackleProbe/InstallGrackleProbe.command

Uninstalling Grackle Probe - disabling load at every startup

Open GrackleProbe/UninstallGrackleProbe.command

Where can I see status info?

For messages from the kernel extension, execute dmesg | grep GrackleProbe
For other information about the Grackle chip, open GrackleProbe/CheckGrackleProbeStatus.command

How do I uninstall GrackleProbe?

Just delete the directory that GrackleProbe.sit uncompressed into.

Benchmarks?

I'd prefer if others in the Mac community gather their own benchmarks. On my own machine under MacOS X 10.2.0, enabling PCI Store Gathering produced these results with Let1kWindowsBloom:

QuartzExtreme off. PCI Store Gathering off.
Total time to create and dispose 1000 windows: 105 seconds (105075695 microseconds) 

QuartzExtreme off. PCI Store Gathering on.
Total time to create and dispose 1000 windows: 98 seconds (98999258 microseconds) 

QuartzExtreme on. PCI Store Gathering off.
Total time to create and dispose 1000 windows: 100 seconds (100762767 microseconds) 

QuartzExtreme on. PCI Store Gathering on.
Total time to create and dispose 1000 windows: 97 seconds (97288812 microseconds)

These tests were done quickly and not scientifically. They may not be reproducible. Your milage may vary.

My machine configuration:
Beige G3, 83MHz system bus, 542MHz speed setting, 640MB RAM, Radeon PCI 32MB.

Download

Grackle Probe

I accept no liability for the suitability, craftsmanship, or use by you in any part. If Grackle Probe works, kudos. If Grackle Probe doesn't, or has some undesirable side effects, that is YOUR responsibility. By downloading or using this software, you agree to this license.

(HTTP) Grackle Probe v1.3 - most recent release version (Freeware)

Interested in squeezing that last bit of performance from your older PowerMac?
Try ROAM, the ROM Accelerator.

History

Nov. 7, 2003: v1.4. No software changes. Noted that GrackleProbe works on MacOS X 10.3.0.
Sep. 11, 2002: v1.4. Switched back to GCC 3.1 for OS X 10.2.0 builds. Changed the Install command to drop files in /Library/StartupItems instead of /System/Library/StartupItems.
Sep. 9, 2002: v1.3. The kext is now compiled twice: once for 10.1.5 and one more time for 10.2.0. The 10.1.5 version should work on at least all of 10.1.x, but should also work on 10.0.x. Loading mechanism changed to work as a StartupItem, or standalone by using the GrackleProbe script or the Resources/grackletool command line program.
Sep. 3, 2002: v1.2 private release. This kext build works on 10.1.5, but not on 10.2.0.
Aug. 28, 2002: v1.1. Complete rewrite. Enables PCI Store Gathering on machines that have Grackle (MPC 106) chips.
Sep. 17, 2001: v1.0. Released to investigate MPC 106 chip features.

Technical observations of the MPC 106

Disabling the MEMGO bit causes a panic. It doesn't seem possible to reconfigure the SDRAM CL/CAS after the machine has booted.
If you boot a PowerMac G3 Gossamer in 66MHz bus mode, the SDRAM CAS mode is set to 2. If you boot the same PowerMac G3 Gossamer in 83MHz system bus mode, the SDRAM CAS mode is set to 3 clocks. I'm not sure why yet. This does seem to explain why setting the system bus clock to 83MHz doesn't seem to speed up the machine though when PC100 CL2 memory is installed.

Other info

This program is my own product and is not representative of the host of these web pages.
The Grackle Probe home page is http://www.stg.com/employees/sbytnar/projects/grackleprobe/index.html

Thanks to my employer, Software Technologies Group, Inc., for hosting my web pages...
..and to everyone else for the feedback.
Products and names mentioned on this page are copyright by their respective holders.
Grackle Probe © 2001, 2002 Steven Bytnar (sbytnar at kagi.com)