case. ### 4. Performance evaluation ## Overview To evaluate the performance of before/after HBASE-21879, we build the following clusters. |service|job|host|cpu|disk|network|comment| |---|---|---|---|---|---|---| SSD|10Gbps|onheap=2g| And we have designed three test cases to prove the performance improvement after HBASE-21879: 1. Disabled BlockCache cache; 2. CacheHitRatio~65%; 3. CacheHitRatio~100% For case.1 and case then it will make so many heap allocations and have a very high GC pressure on heap, while after HBASE-21879 all reads will allocate from pooled offheap bytebuffers and almost no heap allocation. As the cacheHitRatio