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Number crunching :
Why pending credit takes so long?
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LGM Send message Joined: 10 Oct 07 Posts: 5 Credit: 6,640 RAC: 0 |
I'm sure this has been covered in the past, so I apologize for any redundancy. Most of my pending credits go through quickly but I have this one task that has been pending for days now. I was just wondering the usual reasons for when this happens. Thanks in advance, LGM |
purplemkayel Send message Joined: 23 Jul 02 Posts: 1904 Credit: 55,594 RAC: 0 |
Welcome to the SETI forums, Depending on your wingman, credit can take more than a month to arrive. For example, I'm waiting on credit from September... It'll arrive eventually :) Happy birthday Calm Chaos!!! Terrible twos? Calm Chaos... are you feeling it yet? |
John Clark Send message Joined: 29 Sep 99 Posts: 16515 Credit: 4,418,829 RAC: 0 |
My wingman on this WU is so far behind me that I am beginning to think they have left S@H but not told the servers. I completed the WU on August 27th, and still wait my wingman to report! My claimed credit is too high by, I suspect, about 20 cobblestones. It's good to be back amongst friends and colleagues |
Richard Haselgrove Send message Joined: 4 Jul 99 Posts: 14650 Credit: 200,643,578 RAC: 874 |
I'd been thinking of writing up a reply along these lines for a few days, and your question seems as good an excuse for posting it as any, so here goes. At SETI, you can't earn credit by yourself. You have to have a second user, a 'wingman', who crunches the same result and gets near enough the same answer: then you validate each other's work and both get credit. While only one result has been returned, the credit you have claimed shows as 'pending'. Sometimes it seems to stay that way for ages. Why? I can think of four different reasons. 1) Your wingman is slower than you are In the sense that they take longer to return a result that's been issued to them than you do. They may indeed have a much slower computer: they may take part in a much larger number of BOINC projects than you do, and have to spread their computer power more thinly: they may only have their computer turned on for a small proportion of each day: or they may have opted to 'cache' a larger number of results than you do, so you have to wait while the other work is finished before they get to the result you're interested in. All perfectly reasonable choices, and just some of the different ways that BOINC is designed to be used. You just have to wait until their result comes in: it shouldn't be more than a few days. 2) Your wingman has gone missing in action Some people sign up to BOINC and/or SETI, download one or two workunits, and then decide the project doesn't suit them and disappear without a trace. Others do a substantial amount of work, and download hundreds or even thousands of WUs, and then disappear equally suddenly. And it's always possible to suffer a computer breakdown, and not be able to return the work you really intended to finish. When this happens, the BOINC servers wait until the 'deadline' set when the task was issued, and then send another copy to someone else so that the comparison result can be finished off. At the moment, the SETI deadlines are quite long (up to three months), so you can be waiting for this long - plus whatever time your new wingman takes - before your pending credit is granted, but you'll get it in the end. 3) You and your wingman disagree about the result If the results for the two tasks that SETI sends out are different, the servers send out a third copy. When this result comes back in (subject to any of the delays I've described already), the results are checked again. Sometimes all three are 'close enough', and all are awarded credit: sometimes two of them agree (and are awarded credit), but the third is adjudged faulty and gets nothing. If you get the credit, fine: but if yours is the one that gets thrown out, you should investigate further and take remedial action. Is your computer running well (and not overheating)? Are you running the right software? Could you have any faulty (or marginal) hardware components? Are all your software drivers (especially graphics card drivers) up to date? 4) You and you wingman are both fine, but SETI has forgotten to check in your result Not common, but it does happen - I've just posted about it in another thread. All you can do is to alert people to the problem by posting in this message board, and hope that someone with the power to fix it reads your plea. |
MarkTW Send message Joined: 12 Aug 02 Posts: 1 Credit: 10,366,200 RAC: 17 |
I have over 1,000 "credits" pending, which represents nearly a week of production for me. This has been building up for a couple of weeks, I think. Before this, my Pending level has rarely been highr than 200 or 300. Checking the details, I notice that the deadlines for many of the "wingmen" are well into December. Though many pending credits are resolved within a few days, quite a few take the full alotted time, expire, and are then passed on to a new "wingman." This can, and I think does, stretch out some results for a very long time. This has to add to the overhead of the system, maintaining records for extended periods, right? I'm sure it has beeen asked before, but I'm going to ask again, why doesn't the system allocate work units taking the turnaround performance of the computers into consideration? My systems generally turn units around within a couple of days. But I find I'm paired with computers that show turnaround times of more than a week, even as much as 3 weeks. It's irritating even though I know eventually everything will be cleared. |
jedimstr Send message Joined: 23 Oct 00 Posts: 33 Credit: 16,828,887 RAC: 0 |
I have over 1,000 "credits" pending, which represents nearly a week of production for me... snip... Man, I'd be happy with 1,000 credits pending. Here's mine: Pending credit: 30,866.48 |
perryjay Send message Joined: 20 Aug 02 Posts: 3377 Credit: 20,676,751 RAC: 0 |
I'd been thinking of writing up a reply along these lines for a few days, and your question seems as good an excuse for posting it as any, so here goes. Thanks Richard, I hope everyone sees this post. It really explains all the details. I think I've had all of those except the last one. :) PROUD MEMBER OF Team Starfire World BOINC |
W-K 666 Send message Joined: 18 May 99 Posts: 19065 Credit: 40,757,560 RAC: 67 |
For a short period before Multi-Beam was released the initial replication was three. This meant you had two wingmmen for each unit, but the min quorum was two, so if 50% of these wingmen reported quickly you got about 90% of credits granted quickly, 2 to 3 days. You were happy because less than 10% of units went into the pending tray, probably equaling about half of your RAC score. And you only paid scant attention to the other 50% of your wingmen. With MB the replication decreased to two. So now you only have 1 wingman, but these, on average, are of similar performance as before, some fast reports some slow. This still means only about 50% of wingmen will report within 3 days. Therefore only 50% of units, not 90%, will be granted credit quickly. The result lots more pending, for longer periods. Probably equal to 3 or even 4 * your RAC. Now all wingmen are important to you. |
1mp0£173 Send message Joined: 3 Apr 99 Posts: 8423 Credit: 356,897 RAC: 0 |
I have over 1,000 "credits" pending, which represents nearly a week of production for me. This has been building up for a couple of weeks, I think. Before this, my Pending level has rarely been highr than 200 or 300. Checking the details, I notice that the deadlines for many of the "wingmen" are well into December. Though many pending credits are resolved within a few days, quite a few take the full alotted time, expire, and are then passed on to a new "wingman." This can, and I think does, stretch out some results for a very long time. This has to add to the overhead of the system, maintaining records for extended periods, right? I'm sure it has beeen asked before, but I'm going to ask again, why doesn't the system allocate work units taking the turnaround performance of the computers into consideration? My systems generally turn units around within a couple of days. But I find I'm paired with computers that show turnaround times of more than a week, even as much as 3 weeks. It's irritating even though I know eventually everything will be cleared. Remember that BOINC is trying to predict the future. You have a turn-around time of a couple of days. Great. So, (hypothetically) you've got a full cache, deadlines comfortably in the future, but you're going on vacation, and for safety you shut down for a week. ... or the machine dies, and work goes with it. ... or a glitch resets the DCF to something low and the machine downloads TONS of work. This is volunteer computing, and it is very difficult to predict what the volunteers are going to do. |
perryjay Send message Joined: 20 Aug 02 Posts: 3377 Credit: 20,676,751 RAC: 0 |
For a short period before Multi-Beam was released the initial replication was three. This meant you had two wingmmen for each unit, but the min quorum was two, so if 50% of these wingmen reported quickly you got about 90% of credits granted quickly, 2 to 3 days. I liked to watch and /or run in the race for second place. It was fun watching to see who got bumped out of the credits. :) PROUD MEMBER OF Team Starfire World BOINC |
dblEagle Send message Joined: 3 Apr 99 Posts: 136 Credit: 45,641 RAC: 0 |
I think the main reason for the pending credits is because a lot of people haven't switched over to the new Core2 DUO's yet, including me. The difference in computing power is widening. The new Core2 DUO's are about twice as fast and are doing about twice the number of WU's. It takes a slower computer a little while to catch up. |
Dr. C.E.T.I. Send message Joined: 29 Feb 00 Posts: 16019 Credit: 794,685 RAC: 0 |
I think the main reason for the pending credits is because a lot of people haven't switched over to the new Core2 DUO's yet, including me. The difference in computing power is widening. The new Core2 DUO's are about twice as fast and are doing about twice the number of WU's. It takes a slower computer a little while to catch up. and right ya be too . . . most people have to simply just wait for the return - NO biggie - this isn't a race . . . ;))) runs for cover ;) BOINC Wiki . . . Science Status Page . . . |
perryjay Send message Joined: 20 Aug 02 Posts: 3377 Credit: 20,676,751 RAC: 0 |
I think the main reason for the pending credits is because a lot of people haven't switched over to the new Core2 DUO's yet, including me. The difference in computing power is widening. The new Core2 DUO's are about twice as fast and are doing about twice the number of WU's. It takes a slower computer a little while to catch up. Nice thought dbleagle but all 4 of my machines are old and slow but I find myself waiting for core 2 and quads a lot. It seems the faster the machine they have they think they need a larger cache to keep it fed. I run through WUs long before they get to them Through their long cache. PROUD MEMBER OF Team Starfire World BOINC |
Clyde C. Phillips, III Send message Joined: 2 Aug 00 Posts: 1851 Credit: 5,955,047 RAC: 0 |
I have over 1,000 "credits" pending, which represents nearly a week of production for me... snip... Jedi, I have about 1,650 RAC and about 4,000 pendings. That's a little over two daysworth of pendings. You have a similar proportion. I've had around 4,000 pendings for some time. So in your case, it looks like everything is AOK. Hell will freeze over before your pendings will drop to 1,000 (unless the system is changed). For that, mine would have to drop to about 135. |
Andy Lee Robinson Send message Joined: 8 Dec 05 Posts: 630 Credit: 59,973,836 RAC: 0 |
I think the main reason for the pending credits is because a lot of people haven't switched over to the new Core2 DUO's yet, including me. The difference in computing power is widening. The new Core2 DUO's are about twice as fast and are doing about twice the number of WU's. It takes a slower computer a little while to catch up. The huge increase in pendings has absolutely NOTHING to do with the speed of a computer. It has everything to do with the change to 2 instead of 3 to reach quorum, large caches and machines going AWOL for various reasons without any proactive method of reallocating their trapped workunits. A slow computer with a 1 day cache can receive, process *and* return a few results a day. The fastest computer with a 10 day cache will take 10 days to turn around the same workunit if sent at the same time. SETI@home system can't process the workunit further until both crunchers have returned a successful result, so the database fills up with pending workunits. One that is done, then the result can be saved, credit granted and the workunit deleted to make space - workunits are a third of a megabyte each so this is a subtantial amount of data to have lying around unnecessarily. The most effective cache is the *smallest* necessary to ride outages. Big caches are for those few that really do have intermittent access. SETI@Home will run much nicer and smoother if work is turned around quickly with the least amount of work remaining in circulation, and everyone will get credits more quickly. Is that clear now? |
Osiris30 Send message Joined: 19 Aug 07 Posts: 264 Credit: 41,917,631 RAC: 0 |
I have over 1,000 "credits" pending, which represents nearly a week of production for me... snip... Tradesies: Pending credit: 140,738.36 |
Philadelphia Send message Joined: 12 Feb 07 Posts: 1590 Credit: 399,688 RAC: 0 |
I have over 1,000 "credits" pending, which represents nearly a week of production for me... snip... Hmmm, three of you mentioned your pending number and I did a rough calculation to come up with the following: Jedi Mstr - Pending credit: 30,866.48 - RAC: 13,834 - RAC % of PC: 44.8 Clyde C Phillips - PC: ~4,000 - RAC: 1,650 - RAC % of PC: 41.3 Osiris30 - PC: 140,738.36 - RAC: 60,355 - RAC % of PC: 42.9 I wonder if that trend of low 40% is the same for most others too? Probably not but I thought it was interesting that it was true for those three. |
Andy Lee Robinson Send message Joined: 8 Dec 05 Posts: 630 Credit: 59,973,836 RAC: 0 |
I wonder if that trend of low 40% is the same for most others too? Probably not but I thought it was interesting that it was true for those three. 26,649 here, 32.5% (cache 1+1 day). |
dnolan Send message Joined: 30 Aug 01 Posts: 1228 Credit: 47,779,411 RAC: 32 |
Doesn't look like it for me, pending is 25491 as of right now, RAC 13395, so that would be something like 52 - 53%. -Dave |
[KWSN]John Galt 007 Send message Joined: 9 Nov 99 Posts: 2444 Credit: 25,086,197 RAC: 0 |
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