Hi Yun,
Thanks a lot for the detailed and clear explanation, that is very
helpful.
Best
Henry
> 在 2019年6月13日，上午10:32，Yun Gao <yungao...@aliyun.com> 写道：
>
> Hi tao,
>
> As a whole, `networkBufBytes` is not part of the heap. In fact, it is
> allocated from the direct memory. The rough relationship (ignores min/max and
> assumes managed memory is allocated on heap) between the variables are:
>
> Total memory of TM (configured by taskmanager.heap.mb, the name
> may be a little misleading) = heap memory (-XmX) + networkBufBytes.
> networkBufBytes = Total memory of TM * networkBufFraction.
>
> Therefore, the networkBufBytes = xmx / (1 - networkBufFraction) *
> networkBufFraction.
>
> Best,
> Yun
> ------------------------------------------------------------------
> From:徐涛 <happydexu...@gmail.com>
> Send Time:2019 Jun. 13 (Thu.) 10:23
> To:user <user@flink.apache.org>
> Subject:Source code question - about the logic of calculating network buffer
>
> Hi Experts,
> I am debugging the WordCount Flink streaming program in local mode. Flink
> version is 1.7.2
> I saw the following calculation logic about network buffer in class
> TaskManagerServices.
> jvmHeapNoNet is equal to -xmx amount in Java.
> why the networkBufBytes = xmx / (1-networkBufFraction) * networkBufFraction,
> it is a bit strange.
> why it is not calculated by xmx * networkBufFraction?
>
> final long networkBufBytes = Math.min(networkBufMax, Math.max(networkBufMin,
> (long) (jvmHeapNoNet / (1.0 - networkBufFraction) * networkBufFraction)));
>
> Best
> Henry
>
