Computation errors when switching users

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Peter

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Joined: 29 Aug 10
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Australia
Message 34439 - Posted: 30 Aug 2010, 20:29:25 UTC

I get computation errors in MilkyWay@Home 0.24 (cuda23) files when I switch users or shut down/restart. The problem does not occur with MilkyWay@Home 0.19 files. Also have seen the problem with cuda files for Einstein@home.

My machine is an:

Intel i7 930
NVIDIA GeForce GTX 285 (1005MB) driver: 25896
Microsoft Windows 7 x64 Edition, (06.01.7600.00)

Cuda files work fine if I don't swap users.
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Profile Jord
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Netherlands
Message 34442 - Posted: 30 Aug 2010, 20:56:01 UTC - in response to Message 34439.  

Probably something to do with how Windows 7 separates the drivers away from the user account level. You don't say what kind of user account you switch to or from, but if it's to a limited account, then it's very much possible that Session 0 isolation kicks in.

In Windows® XP, Windows Server® 2003, and earlier versions of the Windows operating system, all services run in the same session as the first user who logs on to the console. This session is called Session 0. Running services and user applications together in Session 0 poses a security risk because services run at elevated privilege and therefore are targets for malicious agents who are looking for a way to elevate their own privilege level.

In Windows Vista®, Windows Server 2008, and later versions of Windows, the operating system mitigates this security risk by isolating services in Session 0 and making Session 0 noninteractive. Only system processes and services run in Session 0. The first user logs on to Session 1, and subsequent users log on to subsequent sessions. This means that services never run in the same session as users’ applications and are therefore protected from attacks that originate in application code.


That means that in the middle of doing work on your GPU, BOINC realizes it can't get to the driver for the GPU anymore and it will no longer use it. Simple solution? Don't switch users when using CUDA. It's not something for BOINC to fix.
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Peter

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Message 34444 - Posted: 30 Aug 2010, 22:05:44 UTC - in response to Message 34442.  

Hi,
sounds reasonable. Problem is I share the computer, so don't get much say in when the users switch if I'm not using the machine.

I'll try converting my wife's account to administrator and see if that solves the problem.
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Peter

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Message 34445 - Posted: 30 Aug 2010, 22:14:22 UTC - in response to Message 34444.  

Yes, changing my wife's account to admin seems to solve the problem. Thanks.
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Peter

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Message 34457 - Posted: 31 Aug 2010, 13:16:28 UTC - in response to Message 34445.  

After more running, seems that this didn't solve the problem after all. Wife's account is admin and swapping didin't cause the problem. But sustained use by my wife eventually caused the problem.
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KeeperC

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United Kingdom
Message 34660 - Posted: 13 Sep 2010, 9:55:21 UTC - in response to Message 34457.  

I have exactly the same problem as this. I'm runing Collatz. When my partner switches user so she can use the computer, all Collatz GPU WUs error out immediately. Her account is a limited account. I have installed to allow all users to control BOINC, but when I try from her account it doesn't have the necessary privileges. All CPU WUs continue to run just fine when she switches user.

I don't want to give all other users on this computer admin accounts but it doesn't sound like this is a complete work-around, either.
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Profile Jord
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Message 34703 - Posted: 16 Sep 2010, 20:03:27 UTC

I have forwarded the problem to the developers. They'll look into it after they've dealt with the screen saver is crashing certain systems problem.
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KeeperC

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Message 34716 - Posted: 17 Sep 2010, 8:01:35 UTC - in response to Message 34703.  

I have forwarded the problem to the developers. They'll look into it after they've dealt with the screen saver is crashing certain systems problem.


Great! Thanks.

I've also described my problems on the Collatz boards, here.

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ZPM
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Message 34727 - Posted: 17 Sep 2010, 16:45:47 UTC - in response to Message 34716.  

um, it also crashes on my computer too, ati wu for collatz.
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KeeperC

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Message 34795 - Posted: 21 Sep 2010, 11:06:55 UTC


Just for completeness, to note that I've just started DNETC on this computer and the GPU WUs show exactly the same behaviour.

Thanks
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Message boards : Questions and problems : Computation errors when switching users

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