java - Soft Reference in the role of GC in java

Question

Recently I come across this article which does the GC tuning the Jenkins which talks about this paramter : -XX:SoftRefLRUPolicyMSPerMB

https://jenkins.io/blog/2016/11/21/gc-tuning/

I understand it prevents OOM error, Because it clears the Soft reference object when it reaches to the threshold.

1) What is this threshold (default = 1000ms in -XX:SoftRefLRUPolicyMSPerMB) means? What does this value denotes?

2) My jenkins seems to have 80% of the softreference (observed using HProf)

3) As suggested in the above article, If I reduce this -XX:SoftRefLRUPolicyMSPerMB flag to 10ms What will be consequence?

NOTE : We use G1GC

Thanks,
Harry