[FLINK-2471]Improve File Sink

[ffbin]

FileSinkFunction invoke funtion always call updateCondition, so we can use a variable updateTime to avoid frequent operate (System.currentTimeMillis() - lastTime).

[gyfora]

I don't see that you avoid calling System.currentTimeMillis, you remove one addition and you also add one.

[StephanEwen]

Arithmetic (addition subtraction) in a pipeline is incredibly cheap on today's processors, to this is probably micro optimization ;-)

[ffbin]

In one millisecond, it will call updateCondition about 10000 times and it will do minus operate 10000 times.But update lastTime is less than times of call updateCondition.So i add updateTime to reduce call times of minus operate.

[StephanEwen]

The minus operation is not really evaluated in isolation. It is part of the processor instruction pipeline at that point (see superscalar execution architectures). It will most likely be computed in flight with other instructions without adding overhead, because the pipeline's throughput is at that point not limited by the ALU. Judging the cost or an isolated operation does not work any more on modern processors.

The processing time is in almost all cases dominated stalls in the pipeline doe to fetching variables from memory.

[ffbin]

hi, I can run successfully in local computer,but CI is failed,How can i see why CI is failed?
I can not see the details content ,it is "Do you have a question?".

[StephanEwen]

Can you access this link here? https://travis-ci.org/apache/flink/builds/73886757

[StephanEwen]

BTW: I am not saying we should not merge this. It is actually a fine fix.

I am only trying to help judge the importance of issues, to help deciding what would be important to fix.

[StephanEwen]

If you want to contribute some performance improvements, how about bundling them per component. Something like "Improve File Sink" pull request, where all fixes to the FileSinkFunction go together.

[ffbin]

Hi , i can not access https://travis-ci.org/apache/flink/builds/73886757. Open it , i can only see like this:

[ffbin]

hi, System.currentTimeMillis() is cost performance very much.I want to use a thread to call System.currentTimeMillis and update a static long variable millTime.All other module do not need call System.currentTimeMillis() and can use millTime directly.I have test it can improve performance very much.

[StephanEwen]

Can we close this pull request? I think

The followup idea if adding a "TimeService" with a thread that avoid too frequent calls to System.currentTimeMillis() is an interesting idea...