为提高效率，提问时请提供以下信息，问题描述清晰可优先响应。
- 【TiDB 版本】：
TiKV
Release Version: 4.0.2
Edition: Community
Git Commit Hash: 98ee08c587ab47d9573628aba6da741433d8855c
Git Commit Branch: heads/refs/tags/v4.0.2
UTC Build Time: 2020-07-01 09:34:18
Rust Version: rustc 1.42.0-nightly (0de96d37f 2019-12-19)
Enable Features: jemalloc portable sse protobuf-codec
Profile: dist_release - 【问题描述】：
环境：3PD 32U 64G
3TIKVNODE 48U 384G 4*2T NVME 25GE网口 12TIKV实例
问题：使用go-ycsb压测发现读写延迟较大（超过业务预期，期望99%写入在5us以内），求各位支招优化方案。
测试数据：
#四节点 两节点64线程 两节点96线程 事务单写入
Run finished, takes 10m25.353182752s
INSERT - Takes(s): 625.3, Count: 9997977, OPS: 15989.3, Avg(us): 5931, Min(us): 1257, Max(us): 360724, 99th(us): 18000, 99.9th(us): 38000, 99.99th(us): 142000
Run finished, takes 10m29.663384968s
INSERT - Takes(s): 629.6, Count: 9999345, OPS: 15881.7, Avg(us): 5993, Min(us): 1240, Max(us): 496947, 99th(us): 18000, 99.9th(us): 38000, 99.99th(us): 206000
Run finished, takes 12m56.595600247s
INSERT - Takes(s): 776.5, Count: 9999854, OPS: 12877.6, Avg(us): 4914, Min(us): 1246, Max(us): 497273, 99th(us): 14000, 99.9th(us): 32000, 99.99th(us): 170000
Run finished, takes 13m2.456423591s
INSERT - Takes(s): 782.4, Count: 9999995, OPS: 12781.4, Avg(us): 4949, Min(us): 1261, Max(us): 505101, 99th(us): 14000, 99.9th(us): 29000, 99.99th(us): 125000