[tip:perf/core] perf tools: Do not disable source line lookup just because of 1 failure

[tip-bot for Adrian Hunter]

Commit-ID:  906049c8276eb99af997f73d602649a98e360035
Gitweb:     http://git.kernel.org/tip/906049c8276eb99af997f73d602649a98e360035
Author:     Adrian Hunter <adrian.hunter@xxxxxxxxx>
AuthorDate: Tue, 3 Dec 2013 09:23:10 +0200
Committer:  Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
CommitDate: Wed, 4 Dec 2013 13:46:36 -0300

perf tools: Do not disable source line lookup just because of 1 failure

Looking up an ip's source file name and line number does not succeed
always.  Current logic disables the lookup for a dso entirely on any
failure.  Change it so that disabling never happens if there has ever
been a successful lookup for that dso but disable if the first 123
lookups fail.

Signed-off-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Cc: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Cc: David Ahern <dsahern@xxxxxxxxx>
Cc: Frederic Weisbecker <fweisbec@xxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Mike Galbraith <efault@xxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxx>
Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Cc: Stephane Eranian <eranian@xxxxxxxxxx>
Link: http://lkml.kernel.org/r/1386055390-13757-8-git-send-email-adrian.hunter@xxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
 tools/perf/util/dso.c     |  1 +
 tools/perf/util/dso.h     |  1 +
 tools/perf/util/srcline.c | 20 ++++++++++++++++----
 3 files changed, 18 insertions(+), 4 deletions(-)

diff --git a/tools/perf/util/dso.c b/tools/perf/util/dso.c
index 49da968..a0c7c59 100644
--- a/tools/perf/util/dso.c
+++ b/tools/perf/util/dso.c
@@ -451,6 +451,7 @@ struct dso *dso__new(const char *name)
 		dso->sorted_by_name = 0;
 		dso->has_build_id = 0;
 		dso->has_srcline = 1;
+		dso->a2l_fails = 1;
 		dso->kernel = DSO_TYPE_USER;
 		dso->needs_swap = DSO_SWAP__UNSET;
 		INIT_LIST_HEAD(&dso->node);
diff --git a/tools/perf/util/dso.h b/tools/perf/util/dso.h
index 7142e52..384f2d9 100644
--- a/tools/perf/util/dso.h
+++ b/tools/perf/util/dso.h
@@ -79,6 +79,7 @@ struct dso {
 	struct rb_root	 cache;
 	void		 *a2l;
 	char		 *symsrc_filename;
+	unsigned int	 a2l_fails;
 	enum dso_kernel_type	kernel;
 	enum dso_swap_type	needs_swap;
 	enum dso_binary_type	symtab_type;
diff --git a/tools/perf/util/srcline.c b/tools/perf/util/srcline.c
index 93795f9..0c07556 100644
--- a/tools/perf/util/srcline.c
+++ b/tools/perf/util/srcline.c
@@ -244,6 +244,12 @@ void dso__free_a2l(struct dso *dso __maybe_unused)
 
 #endif /* HAVE_LIBBFD_SUPPORT */
 
+/*
+ * Number of addr2line failures (without success) before disabling it for that
+ * dso.
+ */
+#define A2L_FAIL_LIMIT 123
+
 char *get_srcline(struct dso *dso, unsigned long addr)
 {
 	char *file = NULL;
@@ -268,15 +274,21 @@ char *get_srcline(struct dso *dso, unsigned long addr)
 	if (!addr2line(dso_name, addr, &file, &line, dso))
 		goto out;
 
-	if (asprintf(&srcline, "%s:%u", file, line) < 0)
-		srcline = SRCLINE_UNKNOWN;
+	if (asprintf(&srcline, "%s:%u", file, line) < 0) {
+		free(file);
+		goto out;
+	}
+
+	dso->a2l_fails = 0;
 
 	free(file);
 	return srcline;
 
 out:
-	dso->has_srcline = 0;
-	dso__free_a2l(dso);
+	if (dso->a2l_fails && ++dso->a2l_fails > A2L_FAIL_LIMIT) {
+		dso->has_srcline = 0;
+		dso__free_a2l(dso);
+	}
 	return SRCLINE_UNKNOWN;
 }
 
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