[tip:perf/core] perf script: Make scripting_max_stack value allow for synthesized callchains

[tip-bot for Adrian Hunter]

Commit-ID:  3c5b645faee7afbd417f6127694adbd26778a9eb
Gitweb:     http://git.kernel.org/tip/3c5b645faee7afbd417f6127694adbd26778a9eb
Author:     Adrian Hunter <adrian.hunter@xxxxxxxxx>
AuthorDate: Fri, 25 Sep 2015 16:15:51 +0300
Committer:  Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
CommitDate: Mon, 28 Sep 2015 17:09:41 -0300

perf script: Make scripting_max_stack value allow for synthesized callchains

perf script has a setting to set the maximum stack depth when processing
callchains.  The setting defaults to the hard-coded maximum definition
PERF_MAX_STACK_DEPTH which is 127.

It is possible, when processing instruction traces, to synthesize
callchains.  Synthesized callchains do not have the kernel size
limitation and are whatever size the user requests, although validation
presently prevents the user requested a value greater that 1024.  The
default value is 16.

To allow for synthesized callchains, make the scripting_max_stack value
at least the same size as the synthesized callchain size.

Signed-off-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Link: http://lkml.kernel.org/r/1443186956-18718-21-git-send-email-adrian.hunter@xxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
 tools/perf/builtin-script.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/tools/perf/builtin-script.c b/tools/perf/builtin-script.c
index 5c3c02d..8ce1c6b 100644
--- a/tools/perf/builtin-script.c
+++ b/tools/perf/builtin-script.c
@@ -1748,6 +1748,10 @@ int cmd_script(int argc, const char **argv, const char *prefix __maybe_unused)
 		}
 	}
 
+	if (itrace_synth_opts.callchain &&
+	    itrace_synth_opts.callchain_sz > scripting_max_stack)
+		scripting_max_stack = itrace_synth_opts.callchain_sz;
+
 	/* make sure PERF_EXEC_PATH is set for scripts */
 	perf_set_argv_exec_path(perf_exec_path());
 
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