flink-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Zhangrucong <zhangruc...@huawei.com>
Subject 答复: How to understand slot?
Date Tue, 18 Aug 2015 08:38:08 GMT
Hi stephan, Thanks a lot for answering.

3) For sources, Flink picks a random TaskManager (splits are then assigned locality aware
to the sources). For all tasks after sources, Flink tries to co-locate them with their input(s),
unless they have so many inputs that co-location makes no difference (each parallel reducer
task has all mapper tasks as inputs).

If for sources, Flink picks a random taskmanager. In distributed scene, Some taskmangers run
full task, some taskmangers run litter task, It is not balance?

Thanks!


发件人: ewenstephan@gmail.com [mailto:ewenstephan@gmail.com] 代表 Stephan Ewen
发送时间: 2015年8月18日 16:23
收件人: user@flink.apache.org
主题: Re: How to understand slot?

Hi!

There is a little bit of documentation about the scheduling and the slots

  - In the config reference: https://ci.apache.org/projects/flink/flink-docs-master/setup/config.html#configuring-taskmanager-processing-slots

  - In the internals docs: https://ci.apache.org/projects/flink/flink-docs-master/internals/job_scheduling.html


For <our other questions, here are some brief answers:

1) Shared slots are very useful for pipelined execution. Shared slots mean that (in the example
of MapReduce), one slot can hold one mapper and one reducer. Mappers and reducers run at the
same time when using pipelined execution.

2) A good choice for the number of slots is the number of CPU cores in the processor.

3) For sources, Flink picks a random TaskManager (splits are then assigned locality aware
to the sources). For all tasks after sources, Flink tries to co-locate them with their input(s),
unless they have so many inputs that co-location makes no difference (each parallel reducer
task has all mapper tasks as inputs).


Greetings,
Stephan



On Tue, Aug 18, 2015 at 9:29 AM, Zhangrucong <zhangrucong@huawei.com<mailto:zhangrucong@huawei.com>>
wrote:
When I read the schedule code in job manager. I have flowing questions:


1、  How to decide a job vertex to deploy in a shared slot?  What is the benefit deploy vertexes
in a shared slot?

2、  How to decide a task manager has how many slots?

3、  If there are many task managers, when allocate a new slot, how to decide to use which
slot in which task manger?

4、  If there have detail documents about schedule?



Thank you for any suggestions in advance!





Mime
View raw message