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Running multiple climate models on dual processor CPUs

Running multiple climate models on dual processor CPUs

Questions and Answers : Wish list : Running multiple climate models on dual processor CPUs
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old_user58799

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Message 33762 - Posted: 14 May 2008, 3:56:51 UTC

I have a dual processor computer, 2.8 GHz. When I get a \"C\" model, while it says it will take 4000 hours to complete, but it took 800 hours to get to 10% complete. Therefore, I might assume it will take 8000 hours to complete this model.

To help achieve that, I\'d like to dedicate one processor to just running the \"C\" model.

The other processor I\'d like to rotate between a climate \"S\" model, and some of the other dozen BONIC applications.

I can fake this, in a clumsy manner, by suspending all but 2 models on my computer, the \"C\" model, and what ever other application I want to run. But I need to time it, so I\'m home when the computation ends, so I can Resume the next application. If I\'m wrong, a CPU goes un-used for a period of time.

If I leave Network Activity Always Enabled, then I also need to change the Status of each project to Won\'t Get New Tasks to prevent new tasks being downloaded and taking the processor away from the \"C\" model.
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Message 33763 - Posted: 14 May 2008, 5:18:10 UTC

Dual processor? Your machine has only one CPU. It is a single-core Pentium-4 CPU with Hyperthreading -- which means it has an 18- to 20% boost over a non-Hyperthreading Pentium and the OS pretends it\'s two CPUs. What you want to do with it is fraught with problems.

In my opinion, you\'re asking much more of your machine than it can reasonably deliver.

"We have met the enemy and he is us." -- Pogo
Greetings from coastal Washington state, the scenic US Pacific Northwest.
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Message 33769 - Posted: 14 May 2008, 7:19:32 UTC

Charles, I see you have a HADSM slab model and a HADCM coupled model. The second of these is the really long one that will take a long time to complete. Neither has been processing very fast so far and I wonder whether you could speed them up a bit. Have you got the CPDN screensaver running? If you have, I\'d recommend disabling it because this dynamic screensaver slows the processing down - quite a lot on some computers. You\'d still be able to see your globe\'s progress by clicking the Show graphics button in BOINC manager.

If necessary, set screensaver to a static pic of something completely different, or to None.

A lot of us run climate models but are also attached to other projects. At the moment I have all my other projects set to No New Tasks because I have three really long climate models I need to give priority to. So yes, that\'s one way of helping to control what work the computer gets and runs.

Some people detach from projects they don\'t want work from for the time being. When they want more work from those projects they reattach using the same password as before. This method may keep the BOINC scheduler (which decides what tasks to run when and switches between tasks) happier. While detached, a project doesn\'t accumulate more runtime debt.


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Message 33866 - Posted: 19 May 2008, 8:44:28 UTC - in response to Message 33769.  

True, this is a Hyperthreading CPU, really, I wasn\'t aware it was only 1 CPU. When I run only a single task, Windows XP task manger says that is only getting 50% of my machine, so I needed to tell BONIC to use 2 processors in it\'s options to be able to get to 100%.

What is the CPDN screensaver? The Windows XP screensaver is set to Blank, and kicks in after 3 minutes.

At one time, they had recommended not to leave the BONIC Manager in the Tasks or Download panel, but rather switch to either Projects or Messages, to save the CPU cycles when refreshing those %\'s, even in if the application is minimized, is that still true?

Runtime debt? Oh yeh, read a little about that a long time ago, do I need to be concerned? Guess I\'m afraid if I detach from a project, might not get reconnected again, as I\'ve used different email address over the years for different projects, some which might no longer be valid.


The earlier post about the countdown number on the Show Graphics screen, that\'s neet. How would one ever guess that \"Z\" and \"8\" would do that, what else will is do, is it in some document somewheres?

A \"Time to next checkpoint\" or \"Date/time of next checkpoint\" would be nice.
How about a \"Suspend After Checkpoint\", so BONIC stops the process at the optimum point, for when we need to restart BONIC or reboot the computer?


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Message 33867 - Posted: 19 May 2008, 11:10:25 UTC - in response to Message 33866.  
Last modified: 19 May 2008, 11:14:57 UTC

True, this is a Hyperthreading CPU, really, I wasn\'t aware it was only 1 CPU. When I run only a single task, Windows XP task manger says that is only getting 50% of my machine, so I needed to tell BONIC to use 2 processors in it\'s options to be able to get to 100%.


Others will correct me if I\'m wrong, but I don\'t think you can make a hyperthreaded computer process two project tasks eg two climate models simultaneously. However, although ht computers report in Task manager that they\'re only using 50% of total processing time, this is just the way they report it. In reality your single model will be getting closer to 90% of processing time.

What is the CPDN screensaver? The Windows XP screensaver is set to Blank, and kicks in after 3 minutes.


If your XP screensaver is set to BOINC you\'ll see the graphics of whichever BOINC project task you\'re currently running. If you\'re running the model you\'ll see the model graphics. However, we don\'t recommend running this as a screensaver because it\'s a dynamic screensaver, changing all the time, and takes a lot of CPU cycles. Use the View graphics button in the Tasks tab of BOINC manager instead when you want to see your model. Z then 8 on the keyboard eliminates the overlay.

At one time, they had recommended not to leave the BONIC Manager in the Tasks or Download panel, but rather switch to either Projects or Messages, to save the CPU cycles when refreshing those %\'s, even in if the application is minimized, is that still true?


To use fewest CPU cycles, minimise to a tab where very little happens and changes. Transfers is good for this unless you\'re also running lots of very short tasks from another project.

Runtime debt? Oh yeh, read a little about that a long time ago, do I need to be concerned? Guess I\'m afraid if I detach from a project, might not get reconnected again, as I\'ve used different email address over the years for different projects, some which might no longer be valid.


You should be able to reattach to projects easily. Rejoin as an existing member; this only works if you give the same email address again.

Search for yourself at BoincStats to see what projects you have an account with:

http://boincstats.com/forum/forum_index.php

Just type your username in the box. You seem to have two registrations with several projects including CPDN. The second time you attached to these projects you will have rejoined as a new user and given a different, second, email address. The servers identify us by email address and they won\'t allow you to change an account\'s email address to one that\'s already in use. So it\'s impossible to \'merge\' two accounts on a single project.

This only really matters if you care about your credits total. If there are other projects where you only have one account, you could if necessary change its email address to the address you use on this account in CPDN. And on other projects with 2 accounts, you could get the account with more credits onto the same email address as here. To change account details you have to go into your account on that project.

You may need to bring a third email address into play, albeit temporarily, to do this.

What else can the model graphics display? When you have the graphics window open, type H and you\'ll see the Help menu giving lots of display options.
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Message 33870 - Posted: 19 May 2008, 13:02:22 UTC - in response to Message 33867.  

True, this is a Hyperthreading CPU, really, I wasn\'t aware it was only 1 CPU. When I run only a single task, Windows XP task manger says that is only getting 50% of my machine, so I needed to tell BONIC to use 2 processors in it\'s options to be able to get to 100%.


Others will correct me if I\'m wrong, but I don\'t think you can make a hyperthreaded computer process two project tasks eg two climate models simultaneously. However, although ht computers report in Task manager that they\'re only using 50% of total processing time, this is just the way they report it. In reality your single model will be getting closer to 90% of processing time.

BOINC treats it like 2 CPUs, so you can easily run 2 models (or 1 model and another project) at the same time. But, since it is only 1 CPU, you don\'t get a great deal more throughput (work done per unit time) running 2, than running 1. Maybe 15% more throughput. That\'s not bad, but since the coupled models take so long to process anyway, it takes even longer to finish 1, or 2, if you are running boinc tasks on both of the P4\'s virtual CPUs. It\'s not so bad if running 2 hadms3\'s or hadam3\'s since those are shorter work units.
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Message 33873 - Posted: 19 May 2008, 15:43:55 UTC

The Intel cross-reference for Pentium 4 processors is here. They\'ve persisted with the technology for a surprising length of time.

There is a 2.8 GHz P4 with HT; there is also one without; there are several 2.8 GHz Pentium D processors (which are genuine dual core). However, Pentium D processors normally report on the Web site as such.
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Questions and Answers : Wish list : Running multiple climate models on dual processor CPUs

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