> > > > I am recording here the results from a test VME system using four VF48
waveform digitizers
Last message from this series. After all the tuning, I reduce the trigger rate
from 120 Hz to 100 Hz to see
what happens when the backend computer is not overloaded and has some spare
capacity.
event rate: 100 Hz (down from 120 Hz)
data rate: 37 Mbytes/sec (down from 50 M/s)
mlogger cpu use: 65% (down from 99%)
Attached:
1) trigger rate event plot: now the rate is solid 100 Hz without dropouts
2) CPU and Network plots frog ganglia: the spikes is lazylogger saving mid.gz
files to HDFS storage
3) time structure plots:
a) trigger latency: mean 5 us, most below 10 us, 59 events (0.046%) longer than
100 us, (bottom left graph) 7000 us is longest latency observed.
b) readout time is 7000-8000 us (same as before - VME data rate is independant
from the trigger rate)
c) busy time: mean 7.2 us, 12 events (0.0094%) longer than 10 ms, longest busy
time ever observed is 17 ms (bottom middle graph)
d) time between events is 10 ms (100 Hz pulser trigger), 1 event was missed
about 10 times (spike at 20 ms) (0.0085%), more than 1 event missed never (no
spike at 30 ms, 40 ms, etc).
CPU use on the backend computer:
top - 16:30:59 up 75 days, 35 min, 6 users, load average: 0.98, 0.99, 1.01
Tasks: 206 total, 3 running, 203 sleeping, 0 stopped, 0 zombie
Cpu(s): 39.3%us, 8.2%sy, 0.0%ni, 39.4%id, 5.7%wa, 0.3%hi, 7.2%si, 0.0%st
Mem: 3925556k total, 3404192k used, 521364k free, 8792k buffers
Swap: 32766900k total, 296304k used, 32470596k free, 2477268k cached
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
5826 trinat 20 0 441m 292m 287m R 65.8 7.6 2215:16 mlogger
26756 trinat 20 0 310m 288m 288m S 16.8 7.5 34:32.03 mserver
29005 olchansk 20 0 206m 39m 17m R 14.7 1.0 26:19.42 ana_vf48.exe
7878 olchansk 20 0 99m 3988 740 S 7.7 0.1 27:06.34 sshd
29012 trinat 20 0 314m 288m 288m S 2.8 7.5 4:22.14 mserver
23317 root 20 0 0 0 0 S 1.4 0.0 24:21.52 flush-9:3
K.O. |