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Number crunching :
No Tasks ???
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Send message Joined: 19 Feb 08 Posts: 708 Credit: 4,336,250 RAC: 0 |
I've started running LHC@home on my new HP 635 laptop with AMD E-450 CPU and SLES 11 Linux from SuSE. Let's see what it does. The APU unit has graphic capabilities that are not exploited on this project bur maybe Einstein@home can use them. Tullio It does not use much CPU: about 50%. How come? Sorry, mistake, That was LineVeto in Einstein@home. |
Send message Joined: 6 Sep 08 Posts: 117 Credit: 12,418,570 RAC: 19,037 |
Thanks for the feedback, Eric. I'm amazed that only 50 out of 25,000 hosts seem to have problems. Presumably these rejected results don't validate, or are there additional checks? Good work, all. John. |
Send message Joined: 4 May 07 Posts: 250 Credit: 826,541 RAC: 0 |
Eric, If batches are taking too long to run then you might have someone take a look at any limitations that have been set for the maximum number of Tasks a client can run in any one day. At one time, there were so many number crunching farms out there that as soon as a batch of tasks appeared on the server they got sucked up by these farms and people who wanted to participate but were running only one or two systems never got anything. I have notice in the past few days that if I try to "pump" the Project I will eventually get a message that I have gotten the maximum number of Tasks for the day. I'm not saying open it up to no limit but if one exists then it may need to be tweaked a bit to get the batches done across more BOINC clients. I don't think it is a good idea to totally eliminate validation. SETI use to do three and dropped it to two which seems to be the best approach. That way if the validation fails the Task is fed to a different BOINC client for re-crunching. BTW, I wish I could figure out how to make things work better when running T4T@Home along with other Projects. Since T4T runs outside of BOINC it doesn't play well with others. I'm also seeing a limit in the number of cores that I can use. Don't know why but it seems to have happened with the most recent update to BOINC (7.0.28). Any ideas... anybody? Tom Well I am doing my best,but we have some limitations on the |
Send message Joined: 19 Feb 08 Posts: 708 Credit: 4,336,250 RAC: 0 |
Tom, I am running T4T alongside 6 BOINC projects on my SUN WS and am now trying it on my new HP laptop with Einstein and LHC, all on Linux. tullio |
Send message Joined: 12 Jul 11 Posts: 857 Credit: 1,619,050 RAC: 0 |
Tom; food for thought here. I'll make sure we discuss these issues at the next occasion we can and get back to you. Eric. |
Send message Joined: 4 May 07 Posts: 250 Credit: 826,541 RAC: 0 |
Tom, I am running T4T alongside 6 BOINC projects on my SUN WS and am now trying it on my new HP laptop with Einstein and LHC, all on Linux. Tullio, What setups are you running on the various Projects and on BOINC Manager? I'm on WIndows7 (x64), Intel i7-2600, 16GB RAM. Thanks. Cheers, Tom |
Send message Joined: 12 Jul 11 Posts: 857 Credit: 1,619,050 RAC: 0 |
Well is that really so surprising. I would hope most systems would work correctly! I rely on validation; bit for bit identical results from two work units after some number of Gigaflops!). I also rerun some cases and cross check and finally we once found an outlier point in the physics that was clearly wrong, but that was before the validation using our old in house CPSS. I even found a failing machine in the CERN Computer Centre. I have more work to do here as I cannot prove that I have solved all the numeric issues, but I think I have :-) Hope to publish sson and I hope the paper will be of some interest, funnily enough to Computer Games programmers at least. Eric. |
Send message Joined: 9 Oct 10 Posts: 77 Credit: 3,671,357 RAC: 0 |
Thanks for adding 60k+ tasks ... I hope it will be enough to feed us for the week end ... |
Send message Joined: 12 Jul 11 Posts: 857 Credit: 1,619,050 RAC: 0 |
Doing my best :-) I have another study of about the same size lined up. It is rather exciting actually as this a serious look at the effect of beam-beam in the planned LHC upgrade and is also comparing the two numerical methods of computing the error function of a complex number. Some may be a bit short as we are searching for the limit of the region of beam stability. Eric. |
Send message Joined: 18 Sep 04 Posts: 40 Credit: 60,176 RAC: 0 |
Thanks Eric. I do not remember seeing more that 84k tasks ready to send. :-) Warped |
Send message Joined: 22 Jul 05 Posts: 72 Credit: 3,962,626 RAC: 0 |
If batches are taking too long to run then you might have someone take a look at any limitations that have been set for the maximum number of Tasks a client can run in any one day. Is there such a limit? I don't think there is but I might be wrong. There is certainly a limit on tasks in progress (currently 4 per CPU core) but as soon as a finished task is returned, it seems to be able to be replaced without limit during the day as long as there are tasks 'ready to send' on the server. I haven't noticed any host being told that it has reached a 'daily quota'. At one time, there were so many number crunching farms out there that as soon as a batch of tasks appeared on the server they got sucked up by these farms and people who wanted to participate but were running only one or two systems never got anything. I think this is a misunderstanding of what happened in those days. At the time that 'farm bashing' started happening, batches of work were small and the gaps between batches were weeks and months. Nobody got much work to do. The way BOINC is designed, if requests for work are unsuccessful, the gap between requests will lengthen to the point that the client may not initiate a work request for as long as 24 hours. If a small batch of work suddenly appears, the lucky hosts will be those that just happen to ask for work at the right time. It has nothing to do with whether any particular host is part of a farm or not. I am sure that those individuals (whether owing a single host or a farm) who wanted work desperately enough, could arrange for any particular host to bypass the BOINC backoff and so have a much higher chance of requesting work at the fortuitous moment when new tasks first appeared. I suspect enough people were doing this to deplete the batch so quickly that hosts in extended backoff didn't stand a chance. I have notice in the past few days that if I try to "pump" the Project I will eventually get a message that I have gotten the maximum number of Tasks for the day. The message actually says This computer has reached a limit on tasks in progress. which is fine since hosts are being prevented from caching such large numbers of tasks that others would be prevented from getting their share. Cheers, Gary. |
Send message Joined: 4 May 07 Posts: 250 Credit: 826,541 RAC: 0 |
Tom, I am running T4T alongside 6 BOINC projects on my SUN WS and am now trying it on my new HP laptop with Einstein and LHC, all on Linux. Tullio, Disregard. I managed to fumble my way into getting a lot more work. :) Cheers, Tom |
Send message Joined: 24 Apr 11 Posts: 37 Credit: 1,295,012 RAC: 0 |
Wow, one of my 3.75GHz AMD boxes finished one that took 24 hours... and the wingman is a 1.6GHz Pentium-M that will probably take 3 times longer... Does this mean the equations are turning out more and more relevant data??? :) http://lhcathomeclassic.cern.ch/sixtrack/workunit.php?wuid=2493244 |
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