Sending data to offline system doesn't work reliably

Johanna Steer johanna.steer at ...256...
Tue Jul 26 10:58:22 CEST 2016


i am working on a toolchain monitoring the schedluing behavior of the 
fiasco.oc kernel. The data is monitored through the trace service (quota 
for trace is 2M).
It is then sent to an offline system through an active TCP/IP connection 
and written into a database. VDE is used for that and i am working on 
Ubuntu 14.04.
My problem is that the data isn't sent reliably. I am executing a 
periodic task that returns zero and exits. The only thing that varies is 
the period. After 20 seconds the tasks stop, the monitored data is 
gathered and then sent to the offline system.
The kernel says that it is sending the data, but the system freezes at 
times and the data simply doesn't arrive.
The system reacts quite randomly: Sometimes it sends the files, 
sometimes it doesn't. Sometimes i get an error (shown below). It seems 
easier to send small data sizes (around 200KB), above 700KB hardly 
anything works. In between, it might work or not. As far as i have 
experienced there is no pattern behind it.

I tried the tests before with only 1M quota for trace and the 
reliability improved with 2M quota. However, with 4M it gets worse again 
and the error occures more often.

Here ist the error:

[init -> nic_drv] tx fifo overrun, ignore packet
: spawn id exp6 not open
     while executing
"expect {
         -i $running_spawn_id $platform_msg { puts stderr "Error: 
platform rebooted unexpectedly"; exit -4 }
         -i $running_spawn_id -re $wait_for_re..."
     (procedure "wait_for_output" line 22)
     invoked from within
"wait_for_output $wait_for_re $timeout_value $qemu_spawn_id"
     (procedure "run_log" line 28)
     invoked from within
"run_log $wait_for_re $timeout_value"
     (procedure "run_genode_until" line 28)
     invoked from within
"run_genode_until forever"
     (file "/home/johanna/Bachelorarbeit/genode/repos/dom0/run/" 
line 132)
     invoked from within
"source $include_name"
     ("foreach" body line 6)
     invoked from within
"foreach include_name [get_cmd_arg --include ""] {
     # first check if the include name is absolute
     if {[string first "/" $include_name] == 0} {
         puts ..."
     (file "/home/johanna/Bachelorarbeit/genode/tool/run/run" line 642)

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