JVM 性能波动探究

## performance down when writing, never occur on previous exp

standalone mode and cluster mode both exists, 波浪形变化，持续性流量变小；writer侧并未修改什么东西啊？！ just turn off sync data, why this effect?

波动的原因之一：日志不刷入的影响？NO

syncData=true时表现的更稳定，一般不出现波动，如果出现也是写入很久后出现

writer and server both has no error info, writer's rangeWriter initialized, writer

挤压了较多数据，

maybe due to setting throughput too high? writer has backpressure, writer can't swallow immidiatly, setting little small no effect, must small enough, can see steady effect.

maybe due to rocksDb write too slow?

bkperf occur refCnt = 0 error when the performance decrease

the 波动跟设置较大的direct memory来容纳event应该有关；本来流量大时，撑不住，但因为mem多可以缓冲，所以造成波动，虽然看起来是client侧存在写入瓶颈，数据积压导致空间吃紧，gc频繁，但本质原因是server不能消化掉。

很可能是gc引起的！！

用于统计的recorder占用了过多的资源？不是

server backend error，maybe grpc server related