Does Screensaver do any computing (Mac OSX)

Message boards : Questions and problems : Does Screensaver do any computing (Mac OSX)
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Paul

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Joined: 15 Sep 06
Posts: 5
United Kingdom
Message 65684 - Posted: 1 Dec 2015, 12:27:08 UTC

Hi,
I understand that the screensaver is enough to run BOINC, and that BOINC Manager doesn’t need to be open or running to kick off. That’s great - it’s how I’d ideally like to be running BOINC anyway. No need for an extra application lurking around as I work.

However, I notice a problem. If I quit BOINC Manager, and let the screen saver run for a while, and then restart BOINC Manager, it seems that the work units in the Tasks tab have not been updated. So, one which has an elapsed time of 4:07:35 when I quit BOINC Manager and shows up in the screen saver. The % work for that increases. However, when I stop the screensaver and open BOINC manager, the Tasks tab does not reflect the work done. It shows the information as it was when the application is quit - the extra screensaver time has not been added to the elapsed time, and the % has not changed. I left it running for a couple of hours this morning with just the screensaver running, with no change in the stats presented by BOINC Manager.

When I quit BOINC Manager, a window is shown which says "This will shut down BOINC and its tasks until either the BOINC Manager of the BOINC screen saver is run again".

So, what’s happening? Is BOINC Manager not seeing screen saver work, or is the screensaver not logging/recording work done?

Observed on two machines.

BOINC 7.6.12
Mac OSX 10.11.1 & Max OS X 10.7.5
Running Seti@Home on both
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Richard Haselgrove
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Message 65685 - Posted: 1 Dec 2015, 13:18:37 UTC - in response to Message 65684.  

Not quite. BOINC is actually in four parts:

BOINC Client
BOINC Manager
Screensaver
Project science applications

Of those, the actual computational work is done by the first and the last - the Client and the science applications. They work hand-in-hand - the Client controls the science applications, downloads new work for them, and returns the completed work to the project that needs it.

The Manager purely exists so you can set (and if you wish, monitor) the way BOINC works on your computer. You don't need it to be running all the time - but if you close it down, make sure you don't close the Client as well (unless you mean to). There's an option for that.

The Screensaver is purely that - decorative effects on screen. It doesn't do any computing - though the good ones will reflect the actual work being done under the hood. All screensavers will suck some computing power from your machine - what's used for display can't be used for science. In extreme cases (depending on the relative strength of your computer and its graphics card), a screensaver may consume such a high proportion of the computer's resources that it significantly slows down the real computing.
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noderaser
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Joined: 2 Jan 14
Posts: 276
United States
Message 65713 - Posted: 2 Dec 2015, 3:09:57 UTC

Computing only when the screensaver is active isn't really an option since SETI Classic, the new options are to start computation X minutes after the user has stopped providing input to the computer, if you don't want to compute while the system is in use.
My Detailed BOINC Stats
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Paul

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Joined: 15 Sep 06
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United Kingdom
Message 65717 - Posted: 2 Dec 2015, 12:14:21 UTC

Thanks all. I thought that may be the case, but the screensaver does make me think it’s working (the % values actually increase as it runs). Also that dialogue window you get when you close the BOINC Manager application implies that the screensaver does actual calculations.

I’ll keep BOINC Manager running then.
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Juha
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Message 65723 - Posted: 2 Dec 2015, 20:57:16 UTC

I believe the Mac screensaver is supposed to start the client if it is not already running and also tell the client to exit if the screensaver started it.

In which case, why are % values increasing? Are the apps not checkpointing or did they not start and the screensaver is reporting BOINC's pseudo progress or something else. You may need to dig into the old Event Log messages to find out what's going on. The messages are in stdoutdae.txt (or .old) in BOINC's data directory.
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Message boards : Questions and problems : Does Screensaver do any computing (Mac OSX)

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