Home | About | Sematext search-lucene.com search-hadoop.com
 Search Hadoop and all its subprojects:

Switch to Plain View
MapReduce >> mail # dev >> hadoop1.2.1 speedup model

牛兆捷 2013-09-06, 15:27
牛兆捷 2013-09-06, 15:35
Copy link to this message
Re: hadoop1.2.1 speedup model

Clearly your input size isn't changing. And depending on how they are distributed on the nodes, there could be Datanode/disks contention.

The better way to model this is by scaling the input data also linearly. More nodes should process more data in the same amount of time.


On Sep 6, 2013, at 8:27 AM, 牛兆捷 wrote:

> Hi all:
> I vary the computational nodes of cluster and get the speedup result in attachment.
> In my mind, there are three type of speedup model: linear, sub-linear and super-linear. However the curve of my result seems a little strange. I have attached it.
> <speedup.png>
> This is sort in example.jar, actually it is done only using the default map-reduce mechanism of Hadoop.
> I use hadoop-1.2.1, set 8 map slots and 8 reduce slots per node(12 cpu, 20g men)
>  io.sort.mb = 512, block size = 512mb, heap size = 1024mb,  reduce.slowstart = 0.05, the others are default.
> Input data: 20g, I divide it to 64 files
> Sort example: 64 map tasks, 64 reduce tasks
> Computational nodes: varying from 2 to 9
> Why the speedup mechanism is like this? How can I model it properly?
> Thanks~
> --
> Sincerely,
> Zhaojie
NOTICE: This message is intended for the use of the individual or entity to
which it is addressed and may contain information that is confidential,
privileged and exempt from disclosure under applicable law. If the reader
of this message is not the intended recipient, you are hereby notified that
any printing, copying, dissemination, distribution, disclosure or
forwarding of this communication is strictly prohibited. If you have
received this communication in error, please contact the sender immediately
and delete it from your system. Thank You.
牛兆捷 2013-09-07, 08:33
Robert Evans 2013-09-09, 14:57
牛兆捷 2013-09-10, 02:40