how many mapper tasks do you have set for each node? how many workers are you using for giraph?
On Fri, Oct 18, 2013 at 7:12 PM, YAN Da <[email protected]> wrote: > Dear Claudio Martella, > > I don't quite get what you mean. Our cluster has 15 servers each with 24 > cores, so ideally there can be 15*24 threads/partitions work in parallel, > right? (Perhaps deduct one for ZooKeeper) > > However, when we set the "-Dgiraph.numComputeThreads" option, we find that > we cannot have even 20 threads, and when set to 10, the CPU usage is just > a little bit doubles that of the default setting, not anything close to > 100*numComputeThreads%. > > How can we set it to work on our server to utilize all the processors? > > Regards, > Da Yan > > > It actually depends on the setup of your cluster. > > > > Ideally, with 15 nodes (tasktrackers) you'd want 1 mapper slot per node > > (ideally to run giraph), so that you would have 14 workers, one per > > computing node, plus one for master+zookeeper. Once that is reached, you > > would have a number of compute threads equals to the number of threads > > that > > you can run on each node (24 in your case). > > > > Does this make sense to you? > > > > > > On Thu, Oct 17, 2013 at 5:04 PM, Yi Lu <[email protected]> wrote: > > > >> Hi, > >> > >> I have a computer cluster consisting of 15 slave machines and 1 master > >> machine. > >> > >> On each slave machine, there are two Xeon E5-2620 CPUs. With the help of > >> HT, there are 24 threads. > >> > >> I am wondering how to specify parameters in order to run giraph job in > >> parallel on my cluster. > >> > >> I am using the following parameters to run a pagerank algorithm. > >> > >> hadoop jar ~/giraph-examples.jar org.apache.giraph.GiraphRunner > >> SimplePageRank -vif PageRankInputFormat -vip /input -vof > >> PageRankOutputFormat -op /pagerank -w 1 -mc > >> SimplePageRank\$SimplePageRankMasterCompute -wc > >> SimplePageRank\$SimplePageRankWorkerContext > >> > >> In particular, > >> > >> 1)I know I can use “-w” to specify the number of workers. In my opinion, > >> the number of workers equals to the number of mappers in hadoop except > >> zookeeper. Therefore, in my case(15 slave machine), which number should > >> be > >> chosen? Is 15 a good choice? Since, I find if I input a large number, > >> e.g. > >> 100, the mappers will hang. > >> > >> 2)I know I can use “-Dgiraph.numComputeThreads=1” to specify vertex > >> computing thread number. However, if I specify it to 10, the total > >> runtime > >> is much longer than default. I think the default is 1, which is found in > >> the source code. I wonder if I want to use this parameter, which number > >> should be chosen. > >> > >> 3)When the giraph job is running, I use “top” command to monitor my cpu > >> usage on slave machines. I find that the java process can use 200%-300% > >> cpu > >> resource. However, if I change the number of vertex computing threads to > >> 10, the java process can use 800% cpu resource. I think it is not a > >> linear > >> relation and I want to know why. > >> > >> > >> Thanks for your help. > >> > >> Best, > >> > >> -Yi > >> > > > > > > > > -- > > Claudio Martella > > [email protected] > > > > > -- Claudio Martella [email protected]
