----- On Apr 20, 2021, at 10:55 AM, rostedt rost...@goodmis.org wrote: > On Tue, 20 Apr 2021 09:29:27 -0400 (EDT) > Mathieu Desnoyers <mathieu.desnoy...@efficios.com> wrote: > >> ----- On Apr 20, 2021, at 8:55 AM, rostedt rost...@goodmis.org wrote: >> [...] >> > >> > Would adding automatic module parameters be an issue? That is, you can add >> > in the insmod command line a parameter that will enable tracepoints. We >> > could have a way to even see them from the modinfo. I think I had that >> > working once, and it wasn't really that hard to do. >> >> There is one thing we should consider here in terms of namespacing: those >> module >> command line parameters should be specific to each tracer (e.g. ftrace, perf, >> ebpf). >> >> LTTng for instance already tackles early module load tracing in a different >> way: users can enable instrumentation of yet-to-be loaded kernel modules. So >> it would not make sense in that scheme to have module load parameters. >> >> It's a different trade-off in terms of error reporting though: for instance, >> LTTng won't report an error if a user does a typo when entering an event >> name. >> >> So I think those command line parameters should be tracer-specific, do you >> agree >> ? > > > No, I do not agree. I would like to make it consistent with the kernel > command line. As you can put in: "trace_event=sched_switch" and the > sched_switch trace point will be enable (for the tracefs directory) on boot > up. The same should be for modules as well. > > It shouldn't affect LTTng, as you already have a way to enable them as they > get loaded.
That sounds fine. So that would be within the "trace_event" (and not tracepoint) namespace for module load parameters as well ? Thanks, Mathieu -- Mathieu Desnoyers EfficiOS Inc. http://www.efficios.com
