Djprobe - Kernel probing with the smallest overhead

Direct Jump Probe (djprobe) is an enhancement to kprobe, the existing facility that uses breakpoints to create probes anywhere in the kernel. Djprobe inserts jump instructions instead of breakpoints, thus reducing the overhead of probing. Even though the kprobe "booster" speeds up probing, there still is too much overhead due to probing to allow for the tracing of tens of thousands of events per second without affecting performance.

This presentation will show how the djprobe is designed to insert a jump, discuss the safety of insertion, and describe how the cross self-modification (and so on) is checked. This presentation also provides details on how to use djprobe to speed up probing and shows the performance improvement of djprobe compared to kprobe and kprobe-booster.


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