Commit 05614993 authored by Arnaldo Carvalho de Melo's avatar Arnaldo Carvalho de Melo
Browse files

perf trace: Make --(min,max}-stack imply "--call-graph dwarf" 

If one uses:

  # perf trace --min-stack 16

Then it implicitly means that callgraphs should be enabled, and the best
option in terms of widespread availability is "dwarf".

Further work needed to choose a better alternative, LBR, in capable
systems.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Milian Wolff <milian.wolff@kdab.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-xtjmnpkyk42npekxz3kynzmx@git.kernel.org


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent 0883e820

tools/perf/Documentation/perf-trace.txt

+6 −0
Original line number Diff line number Diff line
@@ -136,12 +136,18 @@ the thread executes on the designated CPUs. Default is to monitor all CPUs. 
        not limiting, the overhead of callchains needs to be set via the

        knobs in --call-graph dwarf.



        Implies '--call-graph dwarf' when --call-graph not present on the

        command line, on systems where DWARF unwinding was built in.



        Default: 127



--min-stack::

        Set the stack depth limit when parsing the callchain, anything

        below the specified depth will be ignored. Disabled by default.



        Implies '--call-graph dwarf' when --call-graph not present on the

        command line, on systems where DWARF unwinding was built in.



--proc-map-timeout::

	When processing pre-existing threads /proc/XXX/mmap, it may take a long time,

	because the file may be huge. A time out is needed in such cases.

tools/perf/builtin-trace.c

+12 −1
Original line number Diff line number Diff line
@@ -3047,7 +3047,7 @@ int cmd_trace(int argc, const char **argv, const char *prefix __maybe_unused) 
		.show_comm = true,

		.trace_syscalls = true,

		.kernel_syscallchains = false,

		.max_stack = PERF_MAX_STACK_DEPTH,

		.max_stack = UINT_MAX,

	};

	const char *output_name = NULL;

	const char *ev_qualifier_str = NULL;
@@ -3109,6 +3109,7 @@ int cmd_trace(int argc, const char **argv, const char *prefix __maybe_unused) 
			"per thread proc mmap processing timeout in ms"),

	OPT_END()

	};

	bool max_stack_user_set = true;

	const char * const trace_subcommands[] = { "record", NULL };

	int err;

	char bf[BUFSIZ];
@@ -3142,6 +3143,16 @@ int cmd_trace(int argc, const char **argv, const char *prefix __maybe_unused) 
		trace.opts.sample_time = true;

	}



	if (trace.max_stack == UINT_MAX) {

		trace.max_stack = PERF_MAX_STACK_DEPTH;

		max_stack_user_set = false;

	}



#ifdef HAVE_DWARF_UNWIND_SUPPORT

	if ((trace.min_stack || max_stack_user_set) && !trace.opts.callgraph_set)

		record_opts__parse_callchain(&trace.opts, &callchain_param, "dwarf", false);

#endif



	if (trace.opts.callgraph_set)

		symbol_conf.use_callchain = true;

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