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Keep Work for xx Days not Working Correctly?

Keep Work for xx Days not Working Correctly?

Questions and Answers : Preferences : Keep Work for xx Days not Working Correctly?
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old_user1075

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Message 1963 - Posted: 28 Aug 2004, 4:45:38 UTC

If my prefs are to keep 1-3 days (or something similar) of work, and given that a CPDN unit is allegedly going to take 800 more hours to process, why does BOINC insist on contacting P@H and S@H to get small bits of work (usually about 11000 seconds per request)? I obviously have a computer attached to all three projects at once.

I am aware of the problem before of BOINC ignoring home vs work vs school settings and using the defaults instead (fixed yet?). I am also aware that S@H and P@H are not compatible with v4. However, these are separate issues.

Does BOINC consider a CPDN work unit to be a trickle instead of the entire run? Is that the reason that BOINC insists on trying to get non-CPDN work when there is still a lot of CPDN work left to do?

I\'m afarid that BOINC will download a S@H/P@H unit but CPDN will crunch past the P@H/S@H return deadline. Either that or the P@H/S@H work will preempt the CPDN work because of the closer return deadline and my CPDN work will go undone for a year.

Didn\'t I read something about being able to share work across a single CPU so that multiple work units could be completed at the same time?

Sorry for the rambling post. Thanks in advance.

derekm
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old_user355

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Message 1966 - Posted: 28 Aug 2004, 6:24:51 UTC

One of the features of 4.xx is pre-emptive scheduling, which will allow BOINC to switch projects every hour. This means you will be able to do work for other projects while still working on the big WUs CPDN has. As soon as the other projects come online with the new CC, we shall see how well this works. :)

No, multiple WUs will never be processed at the same time unless you have a hyper-threaded or multi-CPU system.

And no, the trickles aren't seen as WUs by CPDN, although you do get incremental credits from them. The entire run is the WU.

<a href="http://www.boinc.dk/index.php?page=user_statistics&amp;project=cpdn&amp;userid=355"><img border="0" height="80" src="http://355.cpdn.sig.boinc.dk?188"></a>
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Message 1970 - Posted: 28 Aug 2004, 8:47:25 UTC

To expand on heffed's answer.

The preemptive scheduling system downloads some work (possibly the same amount as the full queue) from each project. That way it will have work on hand to do the project switching when needed. There are some bugs in the preemptive scheduling code. Most of them will not affect CPDN, but will affect projects running alongside of it. I expect they will be fixed before the projects most affected will be publicly released or updated to version 4.
<br>John Keck
BOINCing since 2002/12/08
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Message 1981 - Posted: 28 Aug 2004, 11:05:53 UTC - in response to Message 1966.  

&gt; One of the features of 4.xx is pre-emptive scheduling, which will allow BOINC
&gt; to switch projects every hour. This means you will be able to do work for
&gt; other projects while still working on the big WUs CPDN has. As soon as the
&gt; other projects come online with the new CC, we shall see how well this works.
&gt; :)

That must have been what I read somewhere. Thanks for the reminder. However, I do not see a preference for this under General or CPDN prefs on my account page. Is this behavior controllable? Will BOINC see the fact that there may be a lot of P@H units with short (1-2 day) deadlines and compensate by doing these more often to make sure the deadline is met and then switch to the others (no matter what I put in my individual project prefs for the Resource Share)?

Am I thinking too much about a problem that may not ever exist? Feel free to say I am. It wouldn't be the first time.

derekm
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Message 2018 - Posted: 28 Aug 2004, 19:13:26 UTC - in response to Message 1981.  

&gt; &gt; One of the features of 4.xx is pre-emptive scheduling, which will allow
&gt; BOINC
&gt; &gt; to switch projects every hour. This means you will be able to do work
&gt; for
&gt; &gt; other projects while still working on the big WUs CPDN has. As soon as
&gt; the
&gt; &gt; other projects come online with the new CC, we shall see how well this
&gt; works.
&gt; &gt; :)
&gt;
&gt; That must have been what I read somewhere. Thanks for the reminder. However, I
&gt; do not see a preference for this under General or CPDN prefs on my account
&gt; page. Is this behavior controllable? Will BOINC see the fact that there may be
&gt; a lot of P@H units with short (1-2 day) deadlines and compensate by doing
&gt; these more often to make sure the deadline is met and then switch to the
&gt; others (no matter what I put in my individual project prefs for the Resource
&gt; Share)?
&gt;
&gt; Am I thinking too much about a problem that may not ever exist? Feel free to
&gt; say I am. It wouldn't be the first time.
&gt;
&gt; derekm
&gt; Team MacAddict
&gt;
&gt;
Currently this behavior is not controllable, I hope that will change eventually.

There is a problem with short deadlines/slow computers, hopefully this will be fixed before P@H upgrades to the 4.xx line. Currently the preemptive scheduler ignores deadlines and you can join enough projects to not finish anything on time.
<br>John Keck -- BOINCing since 2002/12/08 <a href="http://www.boinc.dk/index.php?page=user_statistics&amp;project=cpdn&amp;userid=191"><img border="0" height="80" src="http://191.cpdn.sig.boinc.dk?188"></a>
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James Cridland

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Message 2110 - Posted: 30 Aug 2004, 0:48:12 UTC - in response to Message 1966.  

&gt; One of the features of 4.xx is pre-emptive scheduling, which will allow BOINC
&gt; to switch projects every hour. This means you will be able to do work for
&gt; other projects while still working on the big WUs CPDN has. As soon as the
&gt; other projects come online with the new CC, we shall see how well this works.
&gt; :)

Now that SETI have upgraded to v 4, I've today successfully downloaded a SETI work unit to go with my CPDN one. BOINC temporarily stopped my CPDN unit, and is currently chomping through a small SETI unit. Once it's finished, I'm presuming it'll go back to the CPDN unit again.
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Message 2115 - Posted: 30 Aug 2004, 2:45:24 UTC - in response to Message 2110.  


&gt; Now that SETI have upgraded to v 4, I've today successfully downloaded a SETI
&gt; work unit to go with my CPDN one. BOINC temporarily stopped my CPDN unit, and
&gt; is currently chomping through a small SETI unit. Once it's finished, I'm
&gt; presuming it'll go back to the CPDN unit again.
&gt;

Ok, same for me too. It has gone back and forth between the two a few times. However, from what I can tell so far, the Resource Share setting is only for amount of work downloaded at once or in the cache. It has no effect on how often the suspensions take place. It also seems that BOINC tries to keep work in the cache for all projects at once. Therefore, all projects will eventually share CPU time evenly no matter the Resource Share setting unless the scheduler is not responding for a particular project. I really hope this is changed.

derekm
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Message 3479 - Posted: 8 Sep 2004, 18:07:28 UTC - in response to Message 1966.  

Just how big are the CPDN WU's?
BOINC is telling me it will take about 4,000 hours to complete &amp; i have 11 Months to return it in!

WOOOOHOOOOOO!
I came here because BOINC had downloaded a Seti WU about 3 hours ago, yet it hadn't done anything with it, but it just kicked in! (yeah, it's taken me that long to find this thread) :)
42% completed in 12 minutes!



&gt; One of the features of 4.xx is pre-emptive scheduling, which will allow BOINC
&gt; to switch projects every hour. This means you will be able to do work for
&gt; other projects while still working on the big WUs CPDN has. As soon as the
&gt; other projects come online with the new CC, we shall see how well this works.
&gt; :)

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Message 3486 - Posted: 8 Sep 2004, 18:25:54 UTC - in response to Message 3479.  

when you first start the time-to-finish estimate will be way off, but after say 50-100 timesteps it should be a better estimate. It's about 3 weeks to finish a full CPDN workunit (3-phase or 45-year model run) on something like a Pentium IV 2.4GHz computer.
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Message 3549 - Posted: 9 Sep 2004, 2:37:17 UTC - in response to Message 3486.  

&gt; when you first start the time-to-finish estimate will be way off, but after
&gt; say 50-100 timesteps it should be a better estimate. It's about 3 weeks to
&gt; finish a full CPDN workunit (3-phase or 45-year model run) on something like a
&gt; Pentium IV 2.4GHz computer.

Since I started this thread, I'll try to finish it...

BOINC is doing a better job now that 3 of 4 projects are online with v4 (for Mac OS X that's the limit :-( no LHC). I am sure there is some complicated math that throws everything off a little when you start a project and then have another come online a week later at no credit yet. I can't say exactly how close my current time slicing is to my preferences, but we'll call it a work in progress that seems to be heading in the right direction. I predict(!) that when Predictor comes online and BOINC sees my 65+% allocation to it, I'll be a little slow with my CPDN timestep trickles for awhile.

One thing I have noticed is that if I have only CPDN and SETI being crunched at a pref of 10:1 on a dual proc machine, it still likes to preempt the CPDN and run two SETIs at once. You would think any good algorithm wouldn't do that (as shown in an example on the BOINC website). Oh well. I have more important things to worry about in life.
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