(2013/12/06 19:05), Jovi Zhangwei wrote: > On Fri, Dec 6, 2013 at 4:43 PM, Masami Hiramatsu > <masami.hiramatsu...@hitachi.com> wrote: >> (2013/12/05 14:11), Alexei Starovoitov wrote: >>> On Wed, Dec 4, 2013 at 4:05 PM, Masami Hiramatsu >>> <masami.hiramatsu...@hitachi.com> wrote: >>>> (2013/12/04 10:11), Steven Rostedt wrote: >>>>> On Wed, 04 Dec 2013 09:48:44 +0900 >>>>> Masami Hiramatsu <masami.hiramatsu...@hitachi.com> wrote: >>>>> >>>>>> fetch functions and actions. In that case, we can continue >>>>>> to use current interface but much faster to trace. >>>>>> Also, we can see what filter/arguments/actions are set >>>>>> on each event. >>>>> >>>>> There's also the problem that the current filters work with the results >>>>> of what is written to the buffer, not what is passed in by the trace >>>>> point, as that isn't even displayed to the user. >>>> >>>> Agreed, so I've said I doubt this implementation is a good >>>> shape to integrate. Ktap style is better, since it just gets >>>> parameters from perf buffer entry (using event format). >>> >>> Are you saying always store all arguments into ring buffer and let >>> filter run on it? >> >> Yes, it is what ftrace does. I doubt your way fits all of the existing >> trace-event macros. However, I think just for dynamic events, you can >> integrating the argument fetching and filtering. >> > Does this will affect the user interface of perf-probe argument fetching? > > I mean if use bpf backend, do we must need gcc to compile bpf source > for perf-probe argument fetching? as we known, current argument > fetching is go through kprobe_events/uprobe_events debugfs file, and > ktap is based on this behavior.
No, I don't want to do that. Feeding binary code into the kernel is not trusted nor controllable. I'd just like to see the code which optimizing current fetching/filtering methods, and that is possible. Anyway, as far as I can see, there looks be two different models of tracing in our mind. A) Fixed event based tracing: In this model, there are several fixed "events" which well defined with fixed arguments. tracer handles these events and only use limited arguments. It's like a packet stream processing. ftrace, perf etc. are used this model. B) Flexible event-point tracing: In this model, each tracer(or even trace user) can freely define their own event, there will be some fixed tracing points defined, but arguments are defined by users. It's like a debugger's breakpoint debugging. systemtap, ktap etc. are used this model. Of course, both have pros/cons, and can share some fundamental features. e.g. B model has a good flexibility and A model is easy to use for beginners. I think we'd better not integrate these two, but find the better way to share each functionality. Thank you, -- Masami HIRAMATSU IT Management Research Dept. Linux Technology Center Hitachi, Ltd., Yokohama Research Laboratory E-mail: masami.hiramatsu...@hitachi.com -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
