From: Masami Hiramatsu <mhiramat@kernel.org>
To: Steven Rostedt <rostedt@goodmis.org>,
Masami Hiramatsu <mhiramat@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>,
linux-kernel@vger.kernel.org,
Tom Zanussi <tom.zanussi@linux.intel.com>,
Ravi Bangoria <ravi.bangoria@linux.ibm.com>,
Namhyung Kim <namhyung@kernel.org>,
Arnaldo Carvalho de Melo <acme@kernel.org>
Subject: Re: [PATCH v2 00/12] tracing/probe: Add multi-probes per event support
Date: Thu, 4 Jul 2019 15:39:58 +0900 [thread overview]
Message-ID: <20190704153958.16a97c881aebbc5898b1264e@kernel.org> (raw)
In-Reply-To: <156095682948.28024.14190188071338900568.stgit@devnote2>
Hi Steve,
Would you have any comment on this?
Thank you,
On Thu, 20 Jun 2019 00:07:09 +0900
Masami Hiramatsu <mhiramat@kernel.org> wrote:
> Hello,
>
> This is the 2nd version of multi-probes per event support on ftrace
> and perf-tools.
>
> Previous version is here;
> https://lkml.org/lkml/2019/5/31/573
>
> >From this version, I omitted first 9 patches which has been picked
> to Steve's tree.
> In this version, I've fixed some bugs and hardened some unexpected
> error cases according to Steve's comment.
> Here are changes in this version:
>
> - [1/12] This have below changes.
> - Warn if the primary trace_probe does not exist.
> - Fix enable_trace_kprobe() to not return error if the any probes
> are "gone" state. If all probes have gone or any other error
> reason, the event can not be enabled and return error.
> - Fix trace_probe_enable() to roll back all enabled uprobe if
> any one of uprobe is failed to enable.
> - [7/12] Swap the checking order of filename for avoiding unexpected
> memory access.
>
>
> ====
> For trace-event, we can insert same trace-event on several places
> on the code, and those can record similar information as a same event
> with same format.
>
> This series implements similar feature on probe-event. Since the probe
> event is based on the compiled binary, sometimes we find that the target
> source line is complied into several different addresses, e.g. inlined
> function, unrolled loop, etc. In those cases, it is useful to put a
> same probe-event on different addresses.
>
> With this series, we can append multi probes on one event as below
>
> # echo p:testevent _do_fork r1=%ax r2=%dx > kprobe_events
> # echo p:testevent fork_idle r1=%ax r2=%cx >> kprobe_events
> # kprobe_events
> p:kprobes/testevent _do_fork r1=%ax r2=%dx
> p:kprobes/testevent fork_idle r1=%ax r2=%cx
>
> This means testevent is hit on both of _do_fork and fork_idle.
> As you can see, the appended event must have same number of arguments
> and those must have same 'type' and 'name' as original one. This is like
> a function signature, it checks whether the appending event has the same
> type and name of event arguments and same probe type, but doesn't care
> about the assignment.
>
> So, below appending commands will be rejected.
>
> # echo p:testevent _do_fork r1=%ax r2=%dx > kprobe_events
> # echo p:testevent fork_idle r1=%ax >> kprobe_events
> (No 2nd argument)
> # echo p:testevent fork_idle r1=%ax r2=%ax:x8 >> kprobe_events
> (The type of 2nd argument is different)
>
> If one inlined code has an argument on a register, but another
> inlined code has fixed value (as a result of optimization),
> you can also specify the fixed immediate value, e.g.
>
> # echo p:testevent _do_fork r1=%ax r2=%dx > kprobe_events
> # echo p:testevent fork_idle r1=%ax r2=\1 >> kprobe_events
>
>
> Thank you,
>
> ---
>
> Masami Hiramatsu (12):
> tracing/probe: Split trace_event related data from trace_probe
> tracing/dynevent: Delete all matched events
> tracing/dynevent: Pass extra arguments to match operation
> tracing/kprobe: Add multi-probe per event support
> tracing/uprobe: Add multi-probe per uprobe event support
> tracing/kprobe: Add per-probe delete from event
> tracing/uprobe: Add per-probe delete from event
> tracing/probe: Add immediate parameter support
> tracing/probe: Add immediate string parameter support
> selftests/ftrace: Add a testcase for kprobe multiprobe event
> selftests/ftrace: Add syntax error test for immediates
> selftests/ftrace: Add syntax error test for multiprobe
>
>
> Documentation/trace/kprobetrace.rst | 1
> Documentation/trace/uprobetracer.rst | 1
> kernel/trace/trace.c | 8 -
> kernel/trace/trace_dynevent.c | 10 +
> kernel/trace/trace_dynevent.h | 7 -
> kernel/trace/trace_events_hist.c | 4
> kernel/trace/trace_kprobe.c | 241 ++++++++++++++----
> kernel/trace/trace_probe.c | 176 +++++++++++--
> kernel/trace/trace_probe.h | 67 ++++-
> kernel/trace/trace_uprobe.c | 263 +++++++++++++++-----
> tools/testing/selftests/ftrace/test.d/functions | 2
> .../ftrace/test.d/kprobe/kprobe_multiprobe.tc | 35 +++
> .../ftrace/test.d/kprobe/kprobe_syntax_errors.tc | 15 +
> 13 files changed, 665 insertions(+), 165 deletions(-)
> create mode 100644 tools/testing/selftests/ftrace/test.d/kprobe/kprobe_multiprobe.tc
>
> --
> Masami Hiramatsu (Linaro) <mhiramat@kernel.org>
--
Masami Hiramatsu <mhiramat@kernel.org>
next prev parent reply other threads:[~2019-07-04 6:40 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-19 15:07 [PATCH v2 00/12] tracing/probe: Add multi-probes per event support Masami Hiramatsu
2019-06-19 15:07 ` [PATCH v2 01/12] tracing/probe: Split trace_event related data from trace_probe Masami Hiramatsu
2019-06-19 15:07 ` [PATCH v2 02/12] tracing/dynevent: Delete all matched events Masami Hiramatsu
2019-06-19 15:07 ` [PATCH v2 03/12] tracing/dynevent: Pass extra arguments to match operation Masami Hiramatsu
2019-06-19 15:07 ` [PATCH v2 04/12] tracing/kprobe: Add multi-probe per event support Masami Hiramatsu
2019-06-19 15:07 ` [PATCH v2 05/12] tracing/uprobe: Add multi-probe per uprobe " Masami Hiramatsu
2019-06-19 15:08 ` [PATCH v2 06/12] tracing/kprobe: Add per-probe delete from event Masami Hiramatsu
2019-06-19 15:08 ` [PATCH v2 07/12] tracing/uprobe: " Masami Hiramatsu
2019-06-19 15:08 ` [PATCH v2 08/12] tracing/probe: Add immediate parameter support Masami Hiramatsu
2019-06-19 15:08 ` [PATCH v2 09/12] tracing/probe: Add immediate string " Masami Hiramatsu
2019-06-19 15:08 ` [PATCH v2 10/12] selftests/ftrace: Add a testcase for kprobe multiprobe event Masami Hiramatsu
2019-06-19 15:08 ` [PATCH v2 11/12] selftests/ftrace: Add syntax error test for immediates Masami Hiramatsu
2019-06-19 15:09 ` [PATCH v2 12/12] selftests/ftrace: Add syntax error test for multiprobe Masami Hiramatsu
2019-07-04 6:39 ` Masami Hiramatsu [this message]
2019-07-04 11:28 ` [PATCH v2 00/12] tracing/probe: Add multi-probes per event support Steven Rostedt
2019-07-30 6:23 ` Masami Hiramatsu
2019-07-30 15:03 ` Steven Rostedt
2019-07-31 15:25 ` Steven Rostedt
2019-08-01 14:01 ` Masami Hiramatsu
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