On Fri, 18 Jan 2008, Frank Ch. Eigler wrote: > > All this complexity is to be justified by keeping the raw prev/next > pointers from being sent to a naive tracer? It seems to me way out of > proportion.
Damn, and I just blew away all my marker code for something like this ;-) Actually, you just gave me a great idea that I think can help all of us. OK, Mathieu may not be in total agreement, but I think this is the ultimate compromise. We have in sched.c the following marker: trace_mark(kernel_sched_scheduler, "prev %p next %p", prev, next); Then Mathieu can add in some code somewhere (or a module, or something) ret = marker_probe_register("kernel_sched_scheduler", "prev %p next %p", pretty_print_sched_switch, NULL); static void pretty_print_sched_switch(const struct marker *mdata, void *private_data, const char *format, ...) { va_list ap; struct task_struct *prev; struct task_struct *next; va_start(ap, format); prev = va_arg(ap, typeof(prev)); next = va_arg(ap, typeof(next)); va_end; trace_mark(kernel_pretty_print_sched_switch, "prev_pid %d next_pid %d prev_state %ld", prev->pid, next->pid, prev->state); } Then LTTng on startup could arm the normal kernel_sched_switch code and have the user see the nice one. All without adding any more goo or overhead to the non tracing case, and keeping a few critical markers with enough information to be useful to other tracers! Thoughts? -- Steve -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/