[neurosetta] positron experiences and questions

[Trebonius Narcolepticus]

I've synced around 1600 tracks at once several times without trouble... 
But then, I've never had trouble with syncing at all.  Well, I had
trouble with I was trying to use NSM using vmware, but that doesn't
really count.

I have noticed that SMP users have had a lot to complain about both in
Windows and in Linux.  Maybe it's just coincidence.  I think the Neuros'
USB code is a bit fragile.  I hope DI gets it sorted.

<p><p>On Tue, 2003-07-01 at 10:21, Dan Berger wrote:
> Has anyone out there had any success syncing large (i.e. thousands of
> tracks) amounts of music to the Neuros using positron?
> 
> I've observed that aside from general usb-storage instability (the
> device only wants to be mounted once, though rmmod'ing usb-storage
> after unplugging the Neuros and allowing the kernel to re-insert it
> seems to help) my system - a 2x1Gz PIII running the latest SMP errata
> kernel (2.4.20-18.9smp) from redhat - goes all to cock when running a
> sync.
> 
> I left a positron sync running overnight last night and returned to a
> completely hung (not even control-alt-del worked) system this morning.
> 
> So this morning I started it up again, and observed that after syncing
> about 30 tracks, my system load average started climbing.   It got so
> bad that interactive response suffered - the X pointer jumped around
> randomly and I realized things were probably going down hill in a
> hurry.  
> 
> I figured it might be a problem with buffering to or from the USB
> storage driver, so I switched to a text VT and typed 'sync'.
> 
> A minute later, sync hadn't returned - so I switched to another vt and
> did it again.  Still nothing.
> 
> I switched to a third vt and ran top - and noticed that positron and
> both my sync's were in stat "D" meaning un-interruptible  sleep.
> 
> So I killed positron - and within a few minutes the system had
> returned - the load average dropped, and I could use X again.
> 
> As I started typing this message, I started positron again - and sure
> enough - when it hit track 36, the system started seizing up again. 
> This time, I killed it (ctrl-c) before I lost X.
> 
> Anyone having similar experiences?  Given the long startup-time for
> positron (while it scans the sync point), and only being able to sync
> in blocks of 30 - it'll take me days to get my 3000 odd tracks copied
> over.
> 
> So, since positron has a rebuild command - I decided to try syncing
> the files without positron. 
> 
> I fired up rsync
> 
> % rsync -rvP --include=\*.ogg --include=\*.mp3 . /mnt/neuros/music
> 
> My first observation is that doing file reads off the neuros must be
> dog slow - as it's taking rsync forever to decide what files it
> doesn't need to update.
> 
> My second observation is that writes are pretty slow, too - as rsync
> reports about 500kB/s writing files.
> 
> My third observation is that after running for 15 minutes, it's still
> running any my system is behaving pretty normally.  My load average is
> around 2 (vs. 6 or 7 when positron goes haywire) and I can still type
> this message (under X).  
> 
> My fourth observation is that rsync seems to be slowing down as it
> writes more data.  Previous tracks were being written (as I said
> above) at 500kB/s - the last few have averaged between 90kB/s (!) and
> 250kB/s.
> 
> My fifth  and final (at least for now) observation is that during
> those times that rsync is getting poor throughput, my load average
> peaks around 4 - but once that file is written (and flushed, perhaps?)
> the load average drops and rsync continues.
> 
> My conclusion is that what seems to be going on is that positron is
> aggravating a kernel or usb-storage bug - and that rsync, for whatever
> reason, isn't doing the same.
> 
> Can anyone out there corroborate these experiences?  Any comment from
> the positron folk(s)?
> 
> --
> 
> ...Dan Berger [dberger at oubliette.org]
>    http://www.oubliette.org/~dberger
>    Inter arma silent leges
>    A982 E6B1 CB2F 7A49  843A 9297 DA73 4371  1F54 8D0C
> 
>    "Government is not reason. It is not eloquence. It is a force,
>     like fire, a dangerous servant and a terrible master."
> 
>                                       -- George Washington

-- 
Trebonius Narcolepticus <tbone at dirtyredcommie.com>
DRC National Laboratories

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