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Improving Efficiency of switching between projects

Improving Efficiency of switching between projects

Questions and Answers : Wish list : Improving Efficiency of switching between projects
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Message 28188 - Posted: 27 Apr 2007, 16:34:25 UTC
Last modified: 27 Apr 2007, 16:58:34 UTC

I am running CPDN and Einstein BOINC projects. I have set their resource shares to be equal. Generally this means that every 2 hours the BOINC manager switches between the 2 projects.

I am almost positive that this means there is a not insignificant (i.e. about 5%) loss of computation during each switch out of CPDN. This is because when the CPDN project is removed from memory whatever timesteps have been done since the last checkpoint would be lost. Is this correct?

If so this means on average 432/2 = 216 timesteps will be lost each switch. At 3secs (real time) per TS this equates to more than 10 minutes per switch. At 12 swtiches per day (6 from CPDN) this means an hour of CPDN computation lost per day. (Which partly explains my reduced RAC since sharing the resource). Multiply this over the number of users and the number of projects and time to run projects and its an enourmous waste.

Would it be possible for BOINC to check that it has just passed a checkpoint before switching project? Otherwise, if this is correct anyone sharing resource between projects is just wasting time and energy and leading to extra CO2 emissions. If this can\'t be fixed we would all be better off if the users just chose their favourite project and stuck to it.
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Jord
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Message 28191 - Posted: 27 Apr 2007, 16:54:03 UTC - in response to Message 28188.  

Would it be possible for BOINC to check that it has just passed a checkpoint before switching project? Otherwise, if this is correct anyone sharing resource between projects is just wasting time and energy and leading to extra CO2 emissions. If this can\'t be fixed we would all be better off if the users just chose their favourite project and stuck to it.

The 5.8.x versions of BOINC will wait until a checkpoint has been reached before allowing to make the switch between applications. There is that hiatus though that you mentioned, if an earlier checkpoint has been made, Boinc will make the switch anyway.
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Message 28206 - Posted: 27 Apr 2007, 21:08:33 UTC

The project can be set to leave it in memory when suspended, in Preferences, in Your Account. (That way, if the OS ever required the space when CPDN was suspended, CPDN would be swapped out and later restored intact.)

However, with 1.5 GB in your laptop, memory and swapping shouldn\'t be a problem.

"We have met the enemy and he is us." -- Pogo
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Message 28207 - Posted: 27 Apr 2007, 21:36:21 UTC - in response to Message 28206.  

The project can be set to leave it in memory when suspended, in Preferences, in Your Account.



Thanks for that. Preferences changed and problem solved...at least for me. However, there are presumably plenty of other users unaware of this so an enhancement to the way BOINC handles switching would probably result in a decent improvement in efficiency for very little effort. A low hanging piece of fruit waiting to be picked?
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Message 28214 - Posted: 27 Apr 2007, 22:56:02 UTC - in response to Message 28207.  

However, there are presumably plenty of other users unaware of this so an enhancement to the way BOINC handles switching would probably result in a decent improvement in efficiency for very little effort. A low hanging piece of fruit waiting to be picked?

Indecisive as BOINC versions change and not everyone changes their BOINC on all their systems.

And the option to set to leave in memory isn\'t available for all versions of BOINC.
Jord.
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Questions and Answers : Wish list : Improving Efficiency of switching between projects

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