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.
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
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
How do I enable Quartz Extreme for AGP & PCI video cards?
As an Administrator, you can edit the Configuration.plist file
sudo pico /System/Library/Frameworks/ApplicationServices.framework/Versions/A/Frameworks/CoreGraphics.framework/Versions/A/Resources/Configuration.plist
And delete the line that contains
'pico' is a text editor. If you want, use
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.
- PCI Store Gathering should now be enabled on Grackle compatible
Turning on and off PCI Store Gathering
- 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
- PCI Store Gathering should now be enabled on Grackle compatible
Checking the status of Grackle Probe
Installing Grackle Probe - load Grackle Probe at every startup
Uninstalling Grackle Probe - disabling load at every startup
Where can I see status info?
- For messages from the kernel extension, execute
dmesg | grep GrackleProbe
- For other information about the Grackle chip, open
How do I uninstall GrackleProbe?
Just delete the directory that GrackleProbe.sit uncompressed into.
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.
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.
Grackle Probe v1.3 - most recent release version (Freeware)
Interested in squeezing that last bit of performance from your older
Try ROAM, the ROM Accelerator.
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
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
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
Grackle Probe © 2001, 2002 Steven Bytnar (sbytnar at kagi.com)