[sf-lug] GNU Denemo chokes a dual core 2 GB server at the school

[Christian Einfeldt]

I think that we have diagnosed the problem.  It is a runaway process.  The
name of the process is timidity, which is a midi player.  One solution is

ps -A | grep timidity

then

kill [PID for timidity]

Thanks for your thoughts, Jim!

On 9/24/07, jim stockford <jim at well.com> wrote:
>
>
> here's how i understand attacking the problem:
> * watch network traffic to see if the network is overloaded.
> * watch workstations/chubby-clients to see where the CPU is working
> * watch the server to see where the CPU is working
>
>
> On Sep 24, 2007, at 4:09 PM, Christian Einfeldt wrote:
>
> > hi
> >
> > Here is the next issue for our public middle school project. And it
> > is actually part of a recurring theme, it seems: why is our linux lab
> > lagging, when most people think that it should be able to handle what
> > we are throwing at it. My question is fairly long to explain, but
> > simple to summarize: why are we experiencing delays in playing music
> > compositions using GNU Denemo under Edubuntu over a GB network that
> > should be performing better, and what can we do to solve the problem
> > without spending any money?
> >
> > As most of you know from reading this list, I am a volunteer
> > supporting a public middle school with FOSS. We have a brand new dual
> > core server with 2 GB of RAM whose only purpose in life is to support
> > 24 chubby clients running edubuntu. The thin clients have at least
> > 256 MB of RAM, and most of them have swap space on their hard drive
> > also, although some of them are true thin clients in that the hd has
> > no swap and is basically a vestige. I am told that we have a gigabyte
> > network. The server feeds the signal to the first 18 clients through
> > one GB switch, and then that switch feeds another identical switch
> > with services about 6 more clients.
> >
> > Our problem is that when we use GNU Denemo to play the short little
> > compositions that the students write in class, we can have only one
> > student play his / her composition at a time or the system is choked,
> > meaning that it lags. More specifically, all of the students find
> > that their GNOME desktops are almost completely non-responsive to the
> > mouse. The mouse still moves, but programs launch very slowly for
> > about 5 mins, at which time the choke point is presumably cleared, and
> > then one student can again play his / her composition. It might be
> > possible for, say, 2 students or maybe even three students to play
> > their music; but we don't know where that stress point is.
> >
> > And, in some ways, it doesn't even make sense to slowly add students
> > and have them play music, simply because some people who have heard of
> > this problem in passing furrow their brow and say that we shouldn't be
> > having these problems.
> >
> > We are, of course, going to be trying to get more RAM in the clients;
> > and swap for all of the clients; and we have thought of running GNU
> > Denomo natively on each of the clients by booting them as stand alone
> > work stations.
> >
> > For those of you who are familiar with the school, you can stop
> > reading here, because what follows is basic data about the school, and
> > you probably don't need to read it again.
> >
> > >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
> >
> > This inner city school has absolutely no budget for a real tech
> > support person, and all of the teachers already are at work by 6:50
> > a.m., and they usually stay until 6:30 p.m., and then each of the
> > teachers is expected to be available to field phone calls at home
> > until 8 p.m. All of this might sound kind of drastic, but our
> > students typically come to this school of 290 students
> > under-performing their grade level by 2 grade levels, but leave the
> > school as 8th graders typically performing at or above grade level.
> > Seventy-five (75%) of our students come from households below the
> > federal poverty guidelines. 65% of our students are African American;
> > 17% are Latino; 10% are Asian; and 8% are Caucasian. Despite the life
> > challenges facing our students, last year our students tested in first
> > place (as a student body) based on standardized testing. So this
> > school is succeeding in many ways, but they are really struggling in
> > terms of technology, and that is all because of funding shortfalls.
> >
> > Coincidentally, the students spend no time here on Windows boxes,
> > except for occasionally random Internet browsing on a teacher's
> > Windows box. But that is the exception, because, as you can imagine,
> > the teachers don't want the students accessing their computers. So
> > when the students are not in the lab, they are using PClinuxOS boxes
> > in several of the classrooms to do their Internet research.
> >
> > Overall, this school is making miracles with no funding. I am hoping
> > to move the whole school to FOSS eventually, but of course there is
> > still a lot of work to be done. Thus far, the music teacher is fairly
> > impressed with the ability of students to compose music on GNU Denemo,
> > but she would just like to be able to have all of the students listen
> > to their compositions at the same time. Typically, these compositions
> > are no more than, say, 6 or 10 bars long, just enough to get the
> > students familiar with the basics of scales, rests, note duration,
> > tempo, beat, etc. Just the basics.
> >
> > Thanks in advance for the help.
> >
> > --
> > Christian Einfeldt,
> > Producer, The Digital Tipping
> > Point_______________________________________________
> > sf-lug mailing list
> > sf-lug at linuxmafia.com
> > http://linuxmafia.com/mailman/listinfo/sf-lug
>
>


-- 
Christian Einfeldt,
Producer, The Digital Tipping Point
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://linuxmafia.com/pipermail/sf-lug/attachments/20070924/1e743ce4/attachment.html>