dual processor bug (complicated)

[tonyflow]

Has anyone noticed a decrease in network speed in classic apps, when dual processors are enabled?

I noticed the problem first troubleshooting an issue at work, but it seems to even affect downloads in Classic mode MSIE (need to have "Immediately remove items after they have been downloaded" set to perform a clean test). Using CHUD to disable one processor causes the download speed to increase by 1.5x to 2x.

The original scenario was for supporting a legacy business app which runs in Classic mode. One of the operations performed is the import of a file from the Mac desktop into a shared folder on the server. The Import is requested through the client app UI, and then the client initiates the AFP upload behind the scenes.

It all works fine in Classic (the app can find the mounted volume, no problem), but when it is run on a dual processor box the speed slows by a factor of nearly 10. Single CPU macs work fine as does a dual G5 with one CPU disabled (using CHUD).

There is no slowdown if I upload the file by dragging it from Finder into the personal volume.

Does anyone know what might be causing this or what might be done to fix it?

Thanks!

 

[enforce1]

Well, to start is this a g5 or g4 dual set up?

My initial thoughts are that when classic is started on a g5, it COULD knock it down to one processor emulating 32 bit processing (If that makes sense). I could be horribly wrong. If that is true, then, essentially, you're working with a fraction of the power that you normally would be, all while running OSX.... Could cause everything to slow down.

 

[tonyflow]

I've only got a G5 to test on, but I'm pretty sure our customer was using a dual G4. I'm not sure I understand your theory -- why would it be worse than having just one processor running in actuality, as with CHUD? My thought was that there is some inefficiency in communication between the Classic environment and the network stack in OS X, when they do not happen to be running on the same CPU. I don't know anything about SMP really. Maybe there is some way to peg the network code to execute on just one of the processors?