Hello, Kent. On Thu, Mar 28, 2024 at 03:24:35PM -0400, Kent Overstreet wrote: > fs/bcachefs/time_stats.c has some code that's going to be moving out to > lib/ at some point, after I switch it to MAD; if you could hook that up > as well to a few points we could see at a glance if there are stalls > happening in the writeback path. Using BPF (whether through bcc or bpftrace) is likely a better approach for this sort of detailed instrumentation. Fixed debug information is useful and it's also a common occurrence that they don't quite reveal the full picture of what one's trying to understand and one needs to dig a bit deeper, wider, aggregate data in a different way, or whatever. So, rather than adding more fixed infrastructure, I'd suggest adding places which can easily be instrumented using the existing tools (they are really great once you get used to them) whether that's tracepoints or just strategically placed noinline functions. Thanks. -- tejun
