perf tools: Fix usage of max_stack sysctl

tip:perf/urgent tip-bot for Arnaldo Carvalho de Melo 1 participant 1 message May 20, 2016 perf events

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2016-05-20 17:45 UTC #0 lore raw

Commit-ID:  fe176085a4d45fb241c04beea872ecbb8bef6a55
Gitweb:     http://git.kernel.org/tip/fe176085a4d45fb241c04beea872ecbb8bef6a55
Author:     Arnaldo Carvalho de Melo <[email protected]>
AuthorDate: Thu, 19 May 2016 11:34:06 -0300
Committer:  Arnaldo Carvalho de Melo <[email protected]>
CommitDate: Fri, 20 May 2016 11:43:56 -0300

perf tools: Fix usage of max_stack sysctl

We cannot limit processing stacks from the current value of the sysctl, as we may be processing perf.data files, possibly from other machines.

Instead use the old PERF_MAX_STACK_DEPTH, the sysctl default, that can be overriden using --max-stack or equivalent.

Cc Adrian Hunter <[email protected]>

Cc Alexander Shishkin <[email protected]>

Cc Alexei Starovoitov <[email protected]>

Cc Brendan Gregg <[email protected]>

Cc David Ahern <[email protected]>

Cc Frederic Weisbecker <[email protected]>

Cc He Kuang <[email protected]>

Cc Jiri Olsa <[email protected]>

Cc Masami Hiramatsu <[email protected]>

Cc Milian Wolff <[email protected]>

Cc Namhyung Kim <[email protected]>

Cc Peter Zijlstra <[email protected]>

Cc Stephane Eranian <[email protected]>

Cc Thomas Gleixner <[email protected]>

Cc Vince Weaver <[email protected]>

Cc Wang Nan <[email protected]>

Cc Zefan Li <[email protected]>

Fixes 4cb93446c587 ("perf tools: Set the maximum allowed stack from /proc/sys/kernel/perf_event_max_stack")

Link http://lkml.kernel.org/n/[email protected] open here

Signed-off-by Arnaldo Carvalho de Melo <[email protected]>

---
 tools/perf/Documentation/perf-report.txt             | 2 +-
 tools/perf/Documentation/perf-script.txt             | 2 +-
 tools/perf/Documentation/perf-trace.txt              | 3 ++-
 tools/perf/builtin-report.c                          | 2 +-
 tools/perf/builtin-script.c                          | 2 --
 tools/perf/builtin-trace.c                           | 2 +-
 tools/perf/util/db-export.c                          | 3 +--
 tools/perf/util/scripting-engines/trace-event-perl.c | 3 +--
 8 files changed, 8 insertions(+), 11 deletions(-)

tools/perf/Documentation/perf-report.txt +1 -1

index ebaf849..496d42c 100644
@@ -248,7 +248,7 @@ OPTIONS
 	Note that when using the --itrace option the synthesized callchain size
 	will override this value if the synthesized callchain size is bigger.
 
-	Default: /proc/sys/kernel/perf_event_max_stack when present, 127 otherwise.
+	Default: 127
 
 -G::
 --inverted::

tools/perf/Documentation/perf-script.txt +1 -1

index a856a10..4fc44c7 100644
@@ -267,7 +267,7 @@ include::itrace.txt[]
         Note that when using the --itrace option the synthesized callchain size
         will override this value if the synthesized callchain size is bigger.
 
-        Default: /proc/sys/kernel/perf_event_max_stack when present, 127 otherwise.
+        Default: 127
 
 --ns::
 	Use 9 decimal places when displaying time (i.e. show the nanoseconds)

tools/perf/Documentation/perf-trace.txt +2 -1

index 6afe201..1ab0782 100644
@@ -143,7 +143,8 @@ the thread executes on the designated CPUs. Default is to monitor all CPUs.
         Implies '--call-graph dwarf' when --call-graph not present on the
         command line, on systems where DWARF unwinding was built in.
 
-        Default: /proc/sys/kernel/perf_event_max_stack when present, 127 otherwise.
+        Default: /proc/sys/kernel/perf_event_max_stack when present for
+                 live sessions (without --input/-i), 127 otherwise.
 
 --min-stack::
         Set the stack depth limit when parsing the callchain, anything

tools/perf/builtin-report.c +1 -1

index 87d40e3..9bc71c6 100644
@@ -691,7 +691,7 @@ int cmd_report(int argc, const char **argv, const char *prefix __maybe_unused)
 			.ordered_events	 = true,
 			.ordering_requires_timestamps = true,
 		},
-		.max_stack		 = sysctl_perf_event_max_stack,
+		.max_stack		 = PERF_MAX_STACK_DEPTH,
 		.pretty_printing_style	 = "normal",
 		.socket_filter		 = -1,
 	};

tools/perf/builtin-script.c +0 -2

index efca816..0a83f4b 100644
@@ -2067,8 +2067,6 @@ int cmd_script(int argc, const char **argv, const char *prefix __maybe_unused)
 		NULL
 	};
 
-	scripting_max_stack = sysctl_perf_event_max_stack;
-
 	setup_scripting();
 
 	argc = parse_options_subcommand(argc, argv, options, script_subcommands, script_usage,

tools/perf/builtin-trace.c +1 -1

index a2f3aa09..7401de7 100644
@@ -2905,7 +2905,7 @@ int cmd_trace(int argc, const char **argv, const char *prefix __maybe_unused)
 		mmap_pages_user_set = false;
 
 	if (trace.max_stack == UINT_MAX) {
-		trace.max_stack = sysctl_perf_event_max_stack;
+		trace.max_stack = input_name ? PERF_MAX_STACK_DEPTH : sysctl_perf_event_max_stack;
 		max_stack_user_set = false;
 	}

tools/perf/util/db-export.c +1 -2

index 8d96c80..c9a6dc1 100644
@@ -298,8 +298,7 @@ static struct call_path *call_path_from_sample(struct db_export *dbe,
 	 */
 	callchain_param.order = ORDER_CALLER;
 	err = thread__resolve_callchain(thread, &callchain_cursor, evsel,
-					sample, NULL, NULL,
-					sysctl_perf_event_max_stack);
+					sample, NULL, NULL, PERF_MAX_STACK_DEPTH);
 	if (err) {
 		callchain_param.order = saved_order;
 		return NULL;

tools/perf/util/scripting-engines/trace-event-perl.c +1 -2

index 62c7f69..5d1eb1c 100644
@@ -264,8 +264,7 @@ static SV *perl_process_callchain(struct perf_sample *sample,
 		goto exit;
 
 	if (thread__resolve_callchain(al->thread, &callchain_cursor, evsel,
-				      sample, NULL, NULL,
-				      sysctl_perf_event_max_stack) != 0) {
+				      sample, NULL, NULL, scripting_max_stack) != 0) {
 		pr_err("Failed to resolve callchain. Skipping\n");
 		goto exit;
 	}