Hbase-client Meta lookup performance regression between hbase-1 and hbase-2

One of our users complained higher latency after application upgrades from hbase-1.2 client (CDH-5.16.2) to hbase-2.4.5 client with meta replica Load Balance mode during app restart. I reproduced the regression by a test for meta lookup. 

At my test cluster, there are 160k regions for the test table, so there are 160k entries in meta region. Used one thread to do 1 million meta lookup against the meta region server.