question
24 Oct 2005 13:16:13 UTC
Topic 190053
(moderation:
I've been trying to look at my log to learn about the BOINC software and science apps.
So I have a question that I've been twisting over in my brain for the last 2 days.
According to the BOINC Wiki,
"Note:
A Scheduler Request Message for one second's worth of work is equivalent to asking for one Work Unit. "
So in my log, I get a message
"10/20/2005 12:48:36 AM|LHC@home|Requesting 0 seconds of work, returning 1 results"
So here's my question, if 1 second of work = 1 WU, then how can a request for 0 seconds of work return a result?
And here's another message from the log...
"10/21/2005 1:57:08 AM|LHC@home|Requesting 9 seconds of work, returning 0 results
10/21/2005 1:57:13 AM|LHC@home|Scheduler request to http://lhcathome-sched1.cern.ch/scheduler/cgi succeeded
10/21/2005 1:57:14 AM|LHC@home|Started download of woct1B_v6s4hvnom_mqx__17__64.22_59.23__8_10__6__25_1_sixvf_boinc24055.zip"
If I requested 9 seconds of work, and got 0 results, how then do I end up downloading a new WU?
I'm fairly new to all of this, so I hope this isn't a dumb question.
Thanks,
Kathryn
Kathryn :o)
Einstein@Home Moderator
question
)
Hi Kathryn,
The request for work and the return of completed work are opposite ends of the work cycle. A project running under Boinc on your computer (LHC, in the first instance) has at 12:48 AM returned to the server the result of a completed workunit. In your second case, the LHC app running on your computer has decided that it needs another workunit to queue for processing, so it downloaded it from the server.
Regards,
Michael
EDIT - The only dumb question is the one which needed to be asked, but wasn't, for fear of ridicule.
microcraft
"The arc of history is long, but it bends toward justice" - MLK
Simple answer; the message
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Simple answer; the message you're looking at is "two parts"...
"Requesting x seconds of work" means it needs to have more results on your computer to process (or zero, if it's already happy); "returning y results" means it has completed y results and is returning them to the server as 'done'.
The wording is strange because it's telling you "this is what I'm ABOUT to do", and it doesn't know the result yet. Following messages will tell you "ok, server got my request for x seconds of work and now I'm downloading new work" ("starting download"), and "ok, server got my message that I had finished stuff to upload and now I'm uploading it" ("started upload"). It could well request 9876 seconds of work only to be told "sorry, there is no work", or it could say "returning 32 results" only to be told "sorry, project is down".
Just to add a bit more detail
)
Just to add a bit more detail to what Michael said to make things clearer:-
This comment simply means that since work is sent out in whole units only, if your BOINC client calculates that it needs just 1 second of work to make up the required quota, it is going to get a whole work unit anyway. So if an average work unit takes 5,000 seconds to complete, any work request for between 1 and 5,000 seconds will result in just one work unit being downloaded.
This is your BOINC client advising that it has a result that needs returning but it actually doesn't need more work at the moment. Quite often, to save excessive load on the server in making extra requests, the BOINC client can combine the return of result(s) with a request for extra work and do both tasks in the one exchange with the server. In this case however, BOINC decided not to request more work, probably because it was concerned that you had too much already and there might have been a risk of exceeding the deadline.
Because they are two quite separate and distinct tasks that BOINC is attempting to combine into the one server exchange.
9 seconds is a tiny fraction of one work unit but since BOINC has decided that you need a bit more to make up your desired quota, you are going to get a full work unit anyway. Now at the time BOINC decided you needed more work, there just happened to be no completed results ready to return so BOINC is just chatting away and keeping you fully informed as to what it was attempting to do. The following parts of the output you quoted show the successful contact with the scheduling server and the downloading of the new work unit with the most complicated and undecipherable filename ending in ".zip". There would have been a further line you haven't quoted announcing the successful completion of the download. So you should interpret the bit that says "returning 0 results" as simply meaning that BOINC was on the ball and looking for results to return but there simply weren't any at that particular time.
As Michael said, there is really no such thing as a dumb question when dealing with a beast like BOINC. After all look at how extensive the Wiki already is and there is still quite a way to go before it gets anywhere near complete. By that time you'll need a Wiki to explain the Wiki, I'm sure.
Cheers,
Gary.
Thanks everyone! You are
)
Thanks everyone!
You are fantastic.
I'm no computer engineer/software guru, but I want to learn.
I'm in the process of trying to read the wiki (btw, what is a wiki -- does it stand for something?).
Again, thanks :)
Kathryn
Kathryn :o)
Einstein@Home Moderator
RE: I'm in the process of
)
Check out this link to the origin of the term "Wikipedia" but be careful not to browse too deeply as the wealth of information there is quite addictive :).
The unofficial BOINC-Wiki is a collaborative effort by a dedicated group of volunteers, led by Paul D Buck, to create a Wikipedia-like source of information for every conceivable aspect of BOINC and BOINC hosted science projects like EAH. Paul is the driving force and without his untiring efforts, the Wiki probably wouldn't have ever seen the light of day.
Cheers,
Gary.
RE: Thanks everyone! You
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Kathryn,
As I often do, I was just browsing through the Messages Boards and saw this thread. As I am sure you have already realized, Einstein has a large number of knowledgeable and enthusiastic users who willingly volunteer their time to help solve user problems and to discuss issues involving the project. Although my "expertise" may not measure up to those who have already responded here, I would like to offer this small bit of advice.
I noticed, by looking at your "Results for computer" that you have already had a couple of results rejected with "Client error Computing" messages. {You can also see this if you click on KSMarksPsych (in blue to the left of your last post), on "View" Computers, on your "Computer ID", and finally on your "Results".} Most likely, these "Client errors" indicate that you have encountered the "graphics bug" - a problem a lot of people who run Einstein 4.79 and BOINC 4.45 (or later) run into. If you are using the BOINC screensaver or have used the "Show graphics" option under the BOINC "Work" tab, then it is virtually certain that your "Client errors" are a result of the "bug". Basically, if you want to start getting valid results again, you have two choices: 1/ You can stop using the screensaver and "Show graphics" option; or, 2/ You can switch to the Einstein Beta Application (which fixes the graphics bug). If you are interested in trying the Beta App, there is a link to it under More Information on the E@H home page. (I switched to it in early August and I haven't had a "Client error" since. You might also want to do a Message Board "keyword search" on "graphics bug" and learn a little more about it.
Good luck and welcome aboard,
Stick
RE: RE: Thanks
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Thank you so much. I was about to look through the messages to see if I could figure out what was going on.
I have read about the graphics bug, but since I have no idea what kind of graphics card (or the like) my puter has... well, I was a bit lost.
I just put my screen saver back to the picture slide show I had before. I was kind of missing my pictures anyway :)
I'm no so much interested in the screen saver or graphics because I don't know a lot about astronomy and so it was basically a lot of dots on a sphere for me.
I've found the E@H boards to be some of the best :)
Thanks again,
Kathryn
Kathryn :o)
Einstein@Home Moderator
RE: I have read about the
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Most graphics bug reports are about ATI cards but not all (I don't have an ATI card and I got the graphics bug). If you want to find out what kind of graphics card you have, open your Windows "System" Control Panel, click on "Hardware" and then on "Device Manager". Your graphics card will be listed under "Display adapters".
You may also need to restart your system (to clear out any "bug" residuals). And, don't be surprised if the work unit you now have "In Progress" also fails because of the bug.
RE: RE: I have read
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Thanks so much for the advice. I'll make sure to do a reboot right now.
You know... this is a great support forum. I went to the support forum on my blog site and was basically shot down for what I thought was a good question.
Everyone... please keep up the good work. And perhaps someday I'll be able to pay it back by helping a newbie :)
Kathryn
Kathryn :o)
Einstein@Home Moderator