On Mon, May 11, 2026 at 06:08:53PM +0100, Gustavo Luiz Duarte wrote: > > You actually don't need debugfs for this. You can just use bpftrace and > > instrument trace_rcu_ (with other RCU tracing Kconfig options enabled?). I > > had > > something like that working sometime ago. > > My initial attempt to do this using tracepoints was probing > trace_rcu_segcb_stats, but this would add significant overhead to > every callback enqueue/dequeue event which is too expensive for a > production environment
An additional benefit of this debugfs-based approach is that it eliminates the dependency on bpftrace and custom scripts. While instrumenting tracepoints with bpftrace is certainly feasible for a limited number of servers, deploying it fleet-wide becomes problematic. It requires distributing and maintaining additional binaries on every host, just to collect metrics that a few lines of kernel code can expose more efficiently. So while bpftrace can technically accomplish this, it may not be the most appropriate solution for this particular use case.
