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

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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: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Arnaldo Carvalho de Melo 2016-04-15 16:41:19 -03:00
parent 0883e820a0
commit 0561499326
2 changed files with 18 additions and 1 deletions
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6
tools/perf/Documentation/perf-trace.txt
View file

@ -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.

13
tools/perf/builtin-trace.c
View file

@ -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;