Changes between Version 12 and Version 13 of GEMINI/Tutorial/GEC21/GENI_Desktop_and_GEMINI_blipp/ExecuteExperiment

10/22/14 10:11:33 (5 years ago)



  • GEMINI/Tutorial/GEC21/GENI_Desktop_and_GEMINI_blipp/ExecuteExperiment

    v12 v13  
    107107 a. '''Task 3:''' Configure a !NetLogger probe to read the log file and graph the measurements.
     109== __Exercise Task 2 -- Instrument existing application __ ==
     111In this exercise, we will make use of a transparent !NetLogger wrapper than can intercept standard socket calls in existing applications.  This includes read()/write() and send()/recv().  When using the wrapper, you can specify an output file where the log messages are stored as well as the summary interval.  The wrapper uses a version of !NetLogger called NL-Calipers, which calculates and stores in-memory summary statistics over each event encountered.  The NL_INTERVAL
     112variable determines how frequently those summary statistics are reported and the counters reset.
     114The !NetLogger probe instructions above can be used to let BLiPP push the collected NL-Calipers measurements into the measurement store (MS) for graphing and archiving as we did in the previous exercise.  We will use 'iperf' as our test application to instrument with the wrapper library.  The iperf program should already be installed on the GEMINI intrumentized node.  If not, you can 'yum install iperf' or select another application to test with.  The following is an example of how to
     115enable the wrapper using the Linux LD_PRELOAD mechanism (assumes default csh on default Fedora 15 images).
     118    setenv LD_PRELOAD /usr/local/lib/
     119    setenv NL_INTERVAL 1     # default is 1 second summaries
     120    setenv NL_FILE /tmp/iperf.log
     122    iperf -c VM-0 -t 120 -i 2
     123    ------------------------------------------------------------
     124    Client connecting to VM-0, TCP port 5001
     125    TCP window size: 49.7 KByte (default)
     126    ------------------------------------------------------------
     127    [  4] local port 49730 connected with port 5001
     128    [ ID] Interval       Transfer     Bandwidth
     129    [  4]  0.0- 2.0 sec  5.65 GBytes  24.3 Gbits/sec
     130    [  4]  2.0- 4.0 sec  6.48 GBytes  27.8 Gbits/sec
     131    [  4]  4.0- 6.0 sec  6.22 GBytes  26.7 Gbits/sec
     132    [  4]  6.0- 8.0 sec  6.74 GBytes  29.0 Gbits/sec
     133    ...
     135    tail -f /tmp/iperf.log
     136    ts=2014-03-12T02:44:40.734545Z event=wrapper.calipers.write v.sum=2496921600.000000 v.min=131072.000000 v.max=131072.000000 v.mean=131072.000000 r.sum=63101.880412 r.min=0.000654 r.max=5.041231 r.mean=3.312435 g.sum=7558.227539 g.min=0.198364 g.max=1528.854370 g.mean=0.396757 count=19050 dur=1.000013 dur.i=0.990672
     137    ts=2014-03-12T02:44:41.734688Z event=wrapper.calipers.write v.sum=3468034048.000000 v.min=131072.000000 v.max=131072.000000 v.mean=131072.000000 r.sum=94498.685749 r.min=0.612486 r.max=5.041231 r.mean=3.571514 g.sum=7539.329529 g.min=0.198364 g.max=1.632690 g.mean=0.284944 count=26459 dur=1.000008 dur.i=0.988195
     138    ts=2014-03-12T02:44:42.734783Z event=wrapper.calipers.write v.sum=3484024832.000000 v.min=131072.000000 v.max=131072.000000 v.mean=131072.000000 r.sum=94586.291226 r.min=0.217728 r.max=4.854519 r.mean=3.558417 g.sum=7536.308289 g.min=0.205994 g.max=4.592896 g.mean=0.283522 count=26581 dur=1.000032 dur.i=0.987799
     139    ts=2014-03-12T02:44:43.734906Z event=wrapper.calipers.write v.sum=3365928960.000000 v.min=131072.000000 v.max=131072.000000 v.mean=131072.000000 r.sum=89386.429279 r.min=0.422813 r.max=4.854519 r.mean=3.480780 g.sum=7541.175842 g.min=0.205994 g.max=2.365112 g.mean=0.293659 count=25680 dur=1.000017 dur.i=0.988437
     140    ...
     143Once a BLiPP test has been configured for the given node, the event type drop down will contain entries for each of the statistics recorded by the !NetLogger wrapper.  (You will need to wait a minute for the collection to start and then refresh the page.)  In the iperf case, the client performs a number of write() calls to send data to the server.
     145Note that any additional applications started from a shell with the LD_PRELOAD environment variable set will invoke the intercept methods in the wrapper library.
     149Here is a summary of each statistic:
     151* - sum
     153* - mean
     155* - min
     157* - max
     159* - standard deviation.
     163* These statistics are tracked for:
     165*   - 'v': the recorded value
     167*   - 'g': the ratio of the duration(ns)/value (prefix=g for gap)
     169*   - 'r': the ratio of the value/duration(ns) (prefix=r for rate)