Changes between Version 5 and Version 6 of GEMINI/Tutorial/GEC19/GENI_Desktop_and_GEMINI_blipp/ExecuteExperiment
- Timestamp:
- 03/11/14 22:57:25 (10 years ago)
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GEMINI/Tutorial/GEC19/GENI_Desktop_and_GEMINI_blipp/ExecuteExperiment
v5 v6 107 107 == __Exercise Task 2 -- Instrument existing application __ == 108 108 109 In 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 . The !NetLogger probe instructions above can be used to let BLiPP push those measurements into the measurement store for graphing and archiving as we did before.109 In 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 variable determines how frequently those summary statistics are reported and the counters reset. 110 110 111 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 enable the wrapper using the Linux LD_PRELOAD mechanism (assumes default csh on default Fedora 15 images).111 The !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 enable the wrapper using the Linux LD_PRELOAD mechanism (assumes default csh on default Fedora 15 images). 112 112 113 113 {{{ 114 114 setenv LD_PRELOAD /usr/local/lib/nl_wrapper.so 115 setenv NL_INTERVAL 1 # default is 1 second summaries 115 116 setenv NL_FILE /tmp/iperf.log 116 117 … … 141 142 142 143 Here is a summary of each statistic: 143 144 * - count 144 145 145 * - sum 146 146 * - mean … … 150 150 * 151 151 * These statistics are tracked for: 152 * - 'v': the value152 * - 'v': the recorded value 153 153 * - 'g': the ratio of the duration(ns)/value (prefix=g for gap) 154 154 * - 'r': the ratio of the value/duration(ns) (prefix=r for rate)