Github user alpinegizmo commented on a diff in the pull request:
https://github.com/apache/flink/pull/5317#discussion_r162905555
--- Diff: docs/ops/config.md ---
@@ -290,6 +290,12 @@ The following parameters configure Flink's JobManager
and TaskManagers.
- `taskmanager.network.numberOfBuffers` (deprecated, replaced by the three
parameters above): The number of buffers available to the network stack. This
number determines how many streaming data exchange channels a TaskManager can
have at the same time and how well buffered the channels are. If a job is
rejected or you get a warning that the system has not enough buffers available,
increase this value (DEFAULT: **2048**). If set, it will be mapped to
`taskmanager.network.memory.min` and `taskmanager.network.memory.max` based on
`taskmanager.memory.segment-size`.
+- `taskmanager.network.memory.buffers-per-channel`: Number of network
buffers to use for each outgoing/incoming channel (subpartition/input channel).
Especially in credit-based flow control mode, it indicates how many credits are
exclusive in each input channel. It should be configured at least 2 for good
performance. 1 buffer is for receving in-flight data in the subpartition and 1
buffer is for parallel serialization.
+
--- End diff --
This needs some clarification. Is
taskmanager.network.memory.buffers-per-channel only used in credit-based flow
control mode? Does choosing a value greater than 2 provide any benefit?
---
