Posted by Synthetik on December 17, 2020 at 10:00am
Running some multi-thread tests in SA V5.5. So this is the classic effect you get when you take a recursive operation (MSG 3C Rotate processor) and split thread it across multiple cores (6 in this case).
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Here's a tip that explains what i'm talking about when i refer to recursive io connections in MSG.
So i'm ran this on Catalina on a 6 core imac. So notice the image is broken up into 6 bands vertically, which maps out to the # of cores the MSG processor split to run on.
I'm running it in a 3840x2160 pixel canvas.
So here's the MSG preset in the MSG Advanced Editor.
So note that that last 3CRotate processor is using a recursive io connection on the Bus. So this is what introduces the crazy breakup in the image that matches the # of cores you split the processing on.
If i edit it so that the Bus IO connections are not recursive, then i get the following output.
If you just run the MSG effect once, you will see the CPU usage blip up very briefly into somewhere between 100 and 200. The processing is happening so fast you are not seeing the full effect of the multi-processing. It blips by on the CPU usage indicator (using Activity Monitor for this).
But if you run it in loop action, then you get the real stress test. It's running at about 450-490 on the CPU usage indicator then.
Remember, this is a 6 core machine. And xcode and chrome and activity monitor and other crap are eating cpu cycles as well. Plus you always have the overhead of splitting things and sending them off to the various cores, and then waiting for them to call back, so there is always some overhead. So you never see a full 600 because of everything else i just mentioned.
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Here's a tip that explains what i'm talking about when i refer to recursive io connections in MSG.
So i'm ran this on Catalina on a 6 core imac. So notice the image is broken up into 6 bands vertically, which maps out to the # of cores the MSG processor split to run on.
I'm running it in a 3840x2160 pixel canvas.
So here's the MSG preset in the MSG Advanced Editor.
So note that that last 3CRotate processor is using a recursive io connection on the Bus. So this is what introduces the crazy breakup in the image that matches the # of cores you split the processing on.
If i edit it so that the Bus IO connections are not recursive, then i get the following output.
If you just run the MSG effect once, you will see the CPU usage blip up very briefly into somewhere between 100 and 200. The processing is happening so fast you are not seeing the full effect of the multi-processing. It blips by on the CPU usage indicator (using Activity Monitor for this).
But if you run it in loop action, then you get the real stress test. It's running at about 450-490 on the CPU usage indicator then.
Remember, this is a 6 core machine. And xcode and chrome and activity monitor and other crap are eating cpu cycles as well. Plus you always have the overhead of splitting things and sending them off to the various cores, and then waiting for them to call back, so there is always some overhead. So you never see a full 600 because of everything else i just mentioned.