Docs: Update ib validation microbenchmark metrics (#246)

**Description**
Update ib validtion mirobenchmark metrics.

docs/user-tutorial/benchmarks/micro-benchmarks.md

@@ -194,6 +194,23 @@ gpcnet-network-load-test: Select full system network tests run with four congest
 | {benchmark_name}/${test_title}_Alltoall(4096B)_${stat}              | bandwidth (MB/s/rank) | statistical values(Min, Max, Avg, 99%, 99.9%) obtained by all nodes use congestion 'Alltoall (4096 B)' for congestion testing                                              |
 | gpcnet-network-load-test/${test_title}_${network_test_algo}_${stat} | times(x)              | summary about congestion impact factor of every network test algorithm                                                                                                     |
 
+### `ib-traffic`
+
+#### Introduction
+
+Measure the InfiniBand performance under multi nodes' traffic pattern.
+
+The traffic pattern is defined in a config file, which is pre-defined for one-to-many, many-to-one and all-to-all patterns.
+Each row in the config is one round, and all pairs of nodes in a row run ib command simultaneously.
+
+#### Metrics
+                                                              
+| Metrics                    | Unit            | Description                                                                                                                                      |
+| -------------------------- | --------------- | ------------------------------------------------------------------------------------------------------------------------------------------------ |
+| ib-traffic/${command}-${line}-${pair} | bandwidth (MB/s) | The average bandwidth of ib command (ib_write_bw, ib_send_bw, ib_read_bw) run between the ${pair}<sup>th</sup> node pair in the ${line}<sup>th</sup> line of the config |
+| ib-traffic/${command}-${line}-${pair} | time (us)      | The max latency of ib command (ib_write_lat, ib_send_lat, ib_read_lat) run between the ${pair}<sup>th</sup> node pair in the ${line}<sup>th</sup> line of the config    |
+
+
 ## Computation-communication Benchmarks
 
 ### `computation-communication-overlap`