Commit 1a375ae7 authored Sep 19, 2019 by Masami Hiramatsu Committed by Arnaldo Carvalho de Melo Sep 20, 2019

perf probe: Skip same probe address for a given line



Fix to skip making a same probe address on given line.

Since a DWARF line info contains several entries for one line with
different column, perf probe will make a different probe on same address
if user specifies a probe point by "function:line" or "file:line".

e.g.
 $ perf probe -D kernel_read:8
 p:probe/kernel_read_L8 kernel_read+39
 p:probe/kernel_read_L8_1 kernel_read+39

This skips such duplicated probe addresses.

Committer testing:

  # uname -a
  Linux quaco 5.3.0+ #2 SMP Thu Sep 19 16:13:22 -03 2019 x86_64 x86_64 x86_64 GNU/Linux
  #

Before:

  # perf probe -D kernel_read:8
  p:probe/kernel_read _text+3115191
  p:probe/kernel_read_1 _text+3115191
  #

After:

  # perf probe -D kernel_read:8
  p:probe/kernel_read _text+3115191
  #

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lore.kernel.org/lkml/156886447061.10772.4261569305869149178.stgit@devnote2


Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

parent 0216234c

tools/perf/util/probe-finder.c

+19 −0

Original line number	Diff line number	Diff line
		@@ -1245,6 +1245,17 @@ static int expand_probe_args(Dwarf_Die sc_die, struct probe_finder pf,
		return n;
		}

		static bool trace_event_finder_overlap(struct trace_event_finder *tf)
		{
		int i;

		for (i = 0; i < tf->ntevs; i++) {
		if (tf->pf.addr == tf->tevs[i].point.address)
		return true;
		}
		return false;
		}

		/* Add a found probe point into trace event list */
		static int add_probe_trace_event(Dwarf_Die sc_die, struct probe_finder pf)
		{
		@@ -1255,6 +1266,14 @@ static int add_probe_trace_event(Dwarf_Die sc_die, struct probe_finder pf)
		struct perf_probe_arg *args = NULL;
		int ret, i;

		/*
		* For some reason (e.g. different column assigned to same address)
		* This callback can be called with the address which already passed.
		* Ignore it first.
		*/
		if (trace_event_finder_overlap(tf))
		return 0;

		/* Check number of tevs */
		if (tf->ntevs == tf->max_tevs) {
		pr_warning("Too many( > %d) probe point found.\n",

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