Harsh, I wanted to conform about it b'coz in case if it doesn't i want to write code to capture it.
Does it make sense to classify a map/reduce task as I/O bound or cpu bound based on its I/O rate ? Arun On Sat, Dec 3, 2011 at 2:43 PM, Harsh J <ha...@cloudera.com> wrote: > Arun, > > Inline again. > > On 03-Dec-2011, at 12:39 PM, arun k wrote: > > > Q>Does the map/reduce task run time displayed in web GUI is > decent/accurate enough ? > > > Don't see why not. We only display what's been genuinely collected. What > you get out of an API on the CLI is absolutely the same thing. Or perhaps I > do not understand your question completely here - what's led you to ask > this? > > Q>If i want to do find the IO rate of a task, will the task run time > divided by total number of FIle bytes and HDFS bytes read/written give it > approximately ? > > > Yes, that should give you a stop-watch measure. Task start -> Task end, > and the counters the task puts up for itself. > > Q>Does the FILE Bytes read for the reduce task include the map output > record bytes read non-locally over network or the bytes read locally from > the map output records after they are copied locally ? > > > FILE counters are from whatever is read off a local filesystem (file:///), > so would mean the latter. If you look again, you will notice another > counter named "Reduce shuffle bytes" that gives you the former count - > separately. >
