Hi, I'm doing some measurement on hadoop's execution time for my theses. I discovered some steps in the jobs execution time when raising the mappers' execution time continuously. Here is a plot of the execution times with 1, 30 and 60 parallel executing mappers: http://baumbart.drhuim.de/executiontime.gif
The cluster consists of 10 nodes and an overall map task capacity of 60. I'm using hadoop 0.20.2. The many small steps about 1 second are probably caused by the polling interval of the JobClient in monitorAndPrintJob(..) which is about 1 second. But can anyone give me a hint, what's causing the bigger 3 second steps? I suppose it's a polling interval, too. But where? In the Jobtracker? In the Tasktrackers? Thanks for some help and comments, Christian
