Linux 4.x Tracing: Performance Analysis with bcc/BPF
BPF (Berkeley Packet Filter) has been enhanced in the Linux 4.x series and now powers a large collection of performance analysis and observability tools ready for you to use, included in the bcc (BPF Complier Collection) open source project. BPF nowadays can do system tracing, software defined networks, and kernel fast path: much more than just filtering packets! This talk will focus on the bcc/BPF tools for performance analysis, which make use of other built in Linux capabilities: dynamic tracing (kprobes and uprobes) and static tracing (tracepoints and USDT). There are now bcc tools for measuring latency distributions for file system I/O and run queue latency, printing details of storage device I/O and TCP retransmits, investigating blocked stack traces and memory leaks, and a whole lot more. These lead to performance wins large and small, especially when instrumenting areas that previously had zero visibility. Tracing superpowers have finally arrived, built in to Linux.