Screensaver

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Mahbubur

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Message 20384 - Posted: 17 Jul 2006, 15:29:41 UTC

If you have a good gfx card, do you lose a significant amount of cpu cycles that would warrant a blank screensaver rather than the Rosetta one?
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Profile Feet1st
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Message 20406 - Posted: 17 Jul 2006, 20:48:37 UTC - in response to Message 20384.  

If you have a good gfx card, do you lose a significant amount of cpu cycles that would warrant a blank screensaver rather than the Rosetta one?

"Significant"? Probably not. Using none for screen saver would probably be a 3-5% type of improvement. So long as Rosetta can run while the computer is "in use" and is retained in memory when preempted (see General Preferences).
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Running Microsoft's "System Idle Process" will never help cure cancer, AIDS nor Alzheimer's. But running Rosetta@home just might!
https://boinc.bakerlab.org/rosetta/
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Keith Akins

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Message 20428 - Posted: 18 Jul 2006, 2:34:28 UTC

If you accept the default preference setting for the screen saver (10 frames per second/10% Maximum CPU cycles) then Feet1st is right. If Rosetta is primarily a floating point process then is the screensaver? Or is the screensaver an integer?

That too could make a difference, but again on a 2GHZ or greater CPU? Not much.
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Profile dgnuff
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Message 20503 - Posted: 18 Jul 2006, 19:08:08 UTC - in response to Message 20428.  

If you accept the default preference setting for the screen saver (10 frames per second/10% Maximum CPU cycles) then Feet1st is right. If Rosetta is primarily a floating point process then is the screensaver? Or is the screensaver an integer?

That too could make a difference, but again on a 2GHZ or greater CPU? Not much.


The screensaver uses Open GL, which for the most part is floating point. However, it uses comparitively little CPU floating point power, because nearly all of the work is done by the GPU on your graphics card.
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Mats Petersson

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Message 20713 - Posted: 20 Jul 2006, 11:02:47 UTC

It's worth noting that whether the screensaver uses integer or floating point calculations are pretty irrelevant. It still uses up computation power, and if it's supposed to do any significant work, it's going to require some time to run - at which point other work (such as doing the actual protein calculations in Rosetta itself) will be prevented from running. The processor runs code in the form of threads of execution, not as "floating point" or "integer" threads, but once a thread is started, it will run as long as it's allowed by the OS (or until it puts itself to sleep, whichever happens first).

Of course, on a Hyperthreaded processor, it may make a small difference if the second thread is trying hard to use the FPU or not, as the first thread may be able to get exclusive use of the FPU if the other thread isn't using it. But if hyperthreading is available, it's probably also going to run Rosetta on two threads when there is no other "more important" work to be done on the second thread - at which point the FPU will be VERY busy from both threads... So it's pretty moot if the screensaver is competing for the FPU or not, if the rest of the time you have two threads that are both requiring 100% FPU usage...

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Message 20810 - Posted: 21 Jul 2006, 11:29:42 UTC

blank or monoff uses less electricity too!
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Message boards : Number crunching : Screensaver



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