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John Jones - why does welcomeAction seem to keep running

John Jones - why does welcomeAction seem to keep running

by Arnold Pizer -
Number of replies: 0
inactiveTopicwhy does welcomeAction seem to keep running topic started 6/7/2002; 9:49:22 AM
last post 6/11/2002; 3:10:27 PM
userJohn Jones - why does welcomeAction seem to keep running  blueArrow
6/7/2002; 9:49:22 AM (reads: 998, responses: 3)
On our server, which is currently only being used by a small number of people to develop problems, I see several instances of welcomeAction.pl running when I look at the system with top. There will be more instances of welcomeAction than there are people logged into the system, and some of them will be listed as using signifcant cpu time. For example, there are 3 currently running copies each using about 33% of the cpu time.

Has anyone else experienced this?

John

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userArnold K. Pizer - Re: why does welcomeAction seem to keep running  blueArrow
6/11/2002; 6:26:13 AM (reads: 1180, responses: 0)
Hi John,

We do not see that at Rochester. WelcomeAction, when producing hardcopy, will fork off a process but that should not appear as a separate process and even if it did, it might show memory usage but it should not show cpu usage.

Could it be that one person was doing multiple things?

Arnie

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userJohn Jones - Re: why does welcomeAction seem to keep running  blueArrow
6/11/2002; 8:19:21 AM (reads: 1201, responses: 0)
Hi Arnie,

This problem would linger for a long time. I think you are right that there is a connection to hard copy production. Earlier that day, someone ran into another problem: they tried to get hard copy (pdf) of a particular problem set, and the report back was that the document had no data. I have seen this a couple of times from windows pc's.

Here is a guess. There is a bug somewhere in hard copy production, although I don't know what combination of events trigger it. The result (I am still guessing) is an infinite loop with the user getting a message about no data in the hard copy (maybe because of a time out). Meanwhile, the loop still runs in the background.

I will see if I can find a sequence of events which reliably triggers this. Until then, it will probably be pretty hard to track down.

John

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userArnold K. Pizer - Re: why does welcomeAction seem to keep running  blueArrow
6/11/2002; 3:10:27 PM (reads: 1167, responses: 0)
Hi John,

Check for an infinite loop in a problem. These can be subtle. Someone may have written a problem that (depending on the random parameters) sometimes gets into an infinite loop. Then things will persist until welcomeAction times out. One of our Newton method problems originally had this type of bug (there was a while loop so that if the derivative at any stage was zero, then another starting point was chosen but this led to an infinite loop in at least one very rare case). As a test run l2hPrecreateSet and see where it stops. Note that l2hPrecreateSet has no timeout so watch the output.

Arnie

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