Perl 6 - the future is here, just unevenly distributed

IRC log for #webwork, 2015-01-14

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Time Nick Message
00:05 cjmacs` joined #webwork
07:44 soumya joined #webwork
14:31 goehle joined #webwork
15:14 shdw_work joined #webwork
16:09 aubreyja joined #webwork
16:09 aubreyja joined #webwork
16:50 theseb joined #webwork
16:50 theseb can someone help me debug a ANS($ans->cmp()->withPostFilter function with PGML? Here is code and issue...http://webwork.maa.org/moodle/mod/forum/discuss.php?d=3544
16:52 goehle sorry, I don't know much about PGML
16:52 goehle your best bet would be to see if you can get Davide to answer your question
16:57 theseb ok...i don't know that it
16:57 theseb has to do with PGML....
16:57 theseb really i think i just need to debug my ANS thing
16:58 theseb basically i want it to give partial credit if number is right but units are wrong or missing
16:58 theseb that's all
16:58 theseb i can't get it to work.
16:58 theseb goehle: i am willing to switch off PGML if needed to get this to work
16:58 theseb goehle: since it makes my grading take longer for my physics classes big time
16:58 goehle hmm
17:27 goehle asdf
17:36 theseb joined #webwork
17:44 goehle they theseb
17:44 goehle I replied to your forum post
17:44 theseb yay!
17:44 theseb THANK YOU!
17:44 goehle well
17:44 goehle dont thank me yet
17:45 goehle what you are asking for is impossible
17:45 theseb :(
17:45 goehle the issue is that NumberWithUnits accepts equivalently united answers
17:45 goehle i.e. 1 ft or 12 in or whatever
17:45 goehle so it can't even do the comparison without the unit there
17:46 goehle it does print out messages to the student if the units are not provided
17:46 goehle or if they provide units which are not equivalent to the units of the correct answer
17:47 theseb goehle: i see what you mean
18:21 soumya_ joined #webwork
21:24 goehle hey aubreyja
21:24 aubreyja hey
21:25 goehle you have a better feel for this than me.
21:25 aubreyja trying to get reveal.js working
21:25 goehle what is reveal.js?
21:25 aubreyja uh...don't know if I want to commit to that...
21:25 goehle how big of a server do you need to if you want to give a gateway to, say, 40 students simultaneously
21:25 goehle (a gateway with 10-20 problems)
21:25 aubreyja http://lab.hakim.se/reveal-js/#/
21:26 goehle why would a person need a 2 dimensional array of slides?
21:26 aubreyja 40 isn't big. A 32-bit 4 gig machine I think would have worked back in the day
21:26 goehle remember gateways check simultaneously
21:26 goehle and its in class
21:26 aubreyja to be cool man.  I'm going to try using it instead of beamer
21:26 goehle so its, in practice, 400-800 students
21:27 aubreyja yeah, well, the maa server used to be that size believe it or not.
21:27 goehle ok
21:27 aubreyja But, if somebody is having problems with it, then the question I guess is what can they upgrade
21:28 goehle or there there is some kind of misconfiguration somewhere
21:28 aubreyja my guess is that the problem is most likely processor time in that case rather than memory
21:28 aubreyja well, gateways do hit hard. But yeah, it could be an apache config issue. Did he/she look at the MaxChild etc settings?
21:29 goehle I dont know, I'll recommend looking at that
21:29 aubreyja Are there error messages or just slowness?
21:29 goehle I think just slowness, but I will double check about error messages
21:33 goehle hmm
21:33 goehle it wasn't a gateway, it was a single homework with a single question
21:34 goehle the server should easily have handled that
21:39 goehle would max request workers being 20 have caused that aubreyja?
21:39 aubreyja just a sec
21:39 goehle (and does the 20*# of gb extend to 10 gb of memory)
21:43 aubreyja ok, hey, "For WeBWorK a rough rule of thumb is 20 MaxClients per 1 GB of memory"
21:43 goehle yeah
21:43 goehle what happens if that is too low?
21:43 goehle I dont know what maxclients does
21:43 goehle would it cause slowness if its low?
21:43 aubreyja well it's the number of forked apache processes that are allowed
21:44 goehle hmm
21:44 aubreyja when apache starts it spawns like 4 children automatically
21:44 goehle the servers were 87% idle at the time of the quiz
21:44 aubreyja then when a request come in it checks if those are busy and if so spawns a new one up to MaxClients
21:44 aubreyja if it's already at MaxClients then the user has to wait for a free one.
21:45 aubreyja If there are too many max clients it could hog a lot of ram
21:45 aubreyja So, that could cause slowness + idle servers
21:45 goehle this has like 15 gb of ram though
21:45 aubreyja And actually, that recommendation doesn't seem to allow any room for system memory
21:46 goehle w/ 6 processros
21:46 aubreyja So, maybe set it to 10 or something and try that.
21:46 aubreyja Yeah, it should be fine.  This is clearly some config issue.
21:46 aubreyja anything else on the server?
21:46 goehle not really.  Could 40 students overwhelm a wifi access point?
21:46 aubreyja no errors in the apache error log?
21:47 aubreyja I would be surprised if that was the issue, although it could be.
21:47 goehle nothing useful in the error log
21:48 aubreyja well, max clients set at 20 is too much for that rule of thumb. It should be at most 15 according to that. So, that seems like something to try.
21:49 goehle is it?
21:49 goehle its 20 per 1 gb of memory
21:49 goehle and this has 15 gb
21:49 aubreyja oh, wait, did I mis remember it.
21:49 goehle yeah
21:49 goehle I think so
21:49 goehle Its not 1-1
21:50 aubreyja Ok, so try 200 or something (20*10).  I think this is clearly a config issue so I would just start palying with those values. Also theres max_connections in my.cnf for mysql.
21:51 aubreyja What would happen with a value too low is that people would have to get in the request que.  How many students again?
21:51 goehle 40
21:51 goehle it should work with standard settings though
21:51 goehle I would think
21:52 aubreyja yeah, that's true. I would expect it to work with those numbers easily.
21:53 aubreyja I think I'm already sick of reveal.js.
21:54 aubreyja We got the grant submitted by the way.
21:54 goehle nice
21:54 goehle (memory used was a constant 44% through the day)
21:54 goehle cross your fingers and whatnot
21:55 aubreyja We had to make one budget change which is that people we hired as consultants will have to pay $15,000 to start their positions.  You know, goverment cut backs.  Thanks for agreeing in writing to be a consultant.
21:55 goehle I'm pretty sure I left myself an out in that letter ;)
21:55 goehle besides, you are sol on 14k
21:55 goehle or 15k
21:56 goehle or anything above 4k reallty
21:56 aubreyja Nope, no take backs.  We also said that in the grant.
21:56 goehle :)
21:57 aubreyja 44% is a pretty high status quo - that's without people working on it?
21:57 goehle that might be with cash
21:57 goehle cache
21:58 goehle yeah it is
21:58 aubreyja hold on - lemme check the maa server
22:00 goehle yeah the "commit" column in sar was like 16% all day (which is the percentage of memory needed to run the current workload)
22:00 aubreyja maa's load right now is 20%
22:02 goehle if you are using <virtualhost> setups for things like ssl that doesn't change where/how the MaxRequestWorkers, MaxConnectsionsPerChild stuff goes
22:02 goehle right?
22:03 aubreyja no, that's pre-virtual host I'm pretty sure
22:03 aubreyja in other words, I think it's a setting that cannot go in a virtual host config
22:03 goehle what if its after?
22:04 aubreyja after is probably ok, all of the settings just go into a hash all at once when the config files are read
22:04 goehle if the install script cant find an existing place for those settings it puts them at the very end of httpd.conf
22:04 goehle which I think gets run at the very very end
22:05 goehle but I think you are right about the hash
22:05 aubreyja Yes, but it starts up to read the config files and then restarts with those config values I think
22:06 aubreyja apache always does a two-start-start and that's the purpose I think
22:06 goehle makes sense
22:06 goehle well I dont know then
22:06 goehle the server wasn't under any real load
22:06 goehle I increased the MaxRequestWorkers
22:06 goehle and asked them to check if the students could all browse the internet at the same time
22:07 aubreyja hey - I've got to run to pick up my kids but I'll be on later
22:07 goehle later!

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