linux – 什么是锁步采样？

我见过它here for dtrace：

The rate is also increased to 199 Hertz,as capturing kernel stacks is
much less expensive than user-level stacks. The odd numbered rates,99
and 199,are used to avoid sampling in lockstep with other activity
and producing misleading results.

Here for perf：

-F 99: sample at 99 Hertz (samples per second). I’ll sometimes sample faster than this (up to 999 Hertz),but that also costs overhead. 99
Hertz should be negligible. Also,the value ’99’ and not ‘100’ is to
avoid lockstep sampling,which can produce skewed results.

从我所看到的所有剖析器应该避免锁步采样,因为结果可能“倾斜”和“误导”,但我不明白为什么.我想这个问题适用于所有的分析器,但我对linux上的perf感兴趣.