It really depends what you are doing and how you're doing it. If you only pull a few variables out and aggregate their reporting into one printf, then your ove

It really depends what you are doing and how you're doing it. If you only pull a few variables out and aggregate their reporting into one printf, then your overhead is close to one printf. For something like tcp_retransmit_skb that's usually not even noticeable. However if you're performing frequent live calculations on an oft-called function, like every single tcp transmit, like you can definitely introduce too much overhead and negatively affect the system. I'm far from a SystemTap expert, but some low-hanging fruit is to look at what you're doing and see if you can do it fewer times, or see if there's a quicker way or a built-in way to do it already.