Hi, On Thu, Oct 14, 2010 at 10:59 PM, He Chen <airb...@gmail.com> wrote: > they arrived in 1 minute. I understand there will be a setup phase which > will use any free slot no matter map or reduce. >
You mean all jobs were submitted within a minute ? That means a few seconds between jobs ? Or do you mean each job was submitted a minute after the earlier job. Also, which version of Hadoop is this ? > My queue time is the period between the start of Map stage and the time job > is submitted. Because the setup phase has the higher priority than map and > reduce tasks. Any job submitted in the queue will setup no matter how many > previous map and reduce tasks need to be assigned. > > Now, I am sure the job3 setup stage finished earlier than job4's. However, > job3's map stage start later than job4's. BTW, they request same amount of > blocks. > > > On Thu, Oct 14, 2010 at 12:10 PM, abhishek sharma <absha...@usc.edu> wrote: > >> What is the inter-arrival time between these jobs? >> >> There is a "set up" phase for jobs before they are launched. It is >> possible that the order of jobs can change due to slightly different >> set up times. Apart from the number of blocks, it may matter "where" >> these blocks lie. >> >> Abhishek >> >> On Thu, Oct 14, 2010 at 10:06 AM, He Chen <airb...@gmail.com> wrote: >> > Hi all >> > >> > I am testing the performance of my Hadoop clsuters with Hadoop Default >> FIFO >> > schedular. But I find a interesting phenomina. >> > >> > When I submit a series of jobs, some job will be executed earlier even >> they >> > are submitted late. All jobs are request same amount of blocks. For >> example: >> > job 1 submit at time 0 >> > job 2 submit at time 1 >> > job 3 submit at time 2 >> > job 4 submit at time 3 >> > >> > >> > job 4 's queue time is smaller than job3's queue time. This disobey the >> FIFO >> > principle. Any one can give a hint? >> > >> > Thanks >> > >> > Chen >> > >> >
