The '-g/-G' options have already implied function_graph tracer should be
used instead of function tracer. So we don't need extra option '--tracer'
in this case.
This patch changes the behavior as below:
- If '-g' or '-G' option is on, then function_graph tracer is used.
- If '-T' or '-N' option is on, then function tracer is used.
- The function_graph has priority over function tracer.
- The option '--tracer' only take effect if neither -g/-G nor -T/-N
is specified.
Here are some examples.
This will start tracing all functions using default tracer:
$ sudo perf ftrace
This will trace all functions using function graph tracer:
$ sudo perf ftrace -G '*'
This will trace function vfs_read using function graph tracer:
$ sudo perf ftrace -G vfs_read
This will trace function vfs_read using function tracer:
$ sudo perf ftrace -T vfs_read
Signed-off-by: Changbin Du <changbin...@gmail.com>
---
v4: changed tracer selection policy.
v3: remove default '*' for -G/-T.
---
tools/perf/Documentation/perf-config.txt | 5 +--
tools/perf/Documentation/perf-ftrace.txt | 41 +++++++++++++-----------
tools/perf/builtin-ftrace.c | 25 +++++++++++++--
3 files changed, 48 insertions(+), 23 deletions(-)
diff --git a/tools/perf/Documentation/perf-config.txt
b/tools/perf/Documentation/perf-config.txt
index c7d3df5798e2..76408d986aed 100644
--- a/tools/perf/Documentation/perf-config.txt
+++ b/tools/perf/Documentation/perf-config.txt
@@ -614,8 +614,9 @@ trace.*::
ftrace.*::
ftrace.tracer::
- Can be used to select the default tracer. Possible values are
- 'function' and 'function_graph'.
+ Can be used to select the default tracer when neither -G nor
+ -F option is not specified. Possible values are 'function' and
+ 'function_graph'.
llvm.*::
llvm.clang-path::
diff --git a/tools/perf/Documentation/perf-ftrace.txt
b/tools/perf/Documentation/perf-ftrace.txt
index b80c84307dc9..821d4d334a09 100644
--- a/tools/perf/Documentation/perf-ftrace.txt
+++ b/tools/perf/Documentation/perf-ftrace.txt
@@ -24,7 +24,8 @@ OPTIONS
-t::
--tracer=::
- Tracer to use: function_graph or function.
+ Tracer to use when neither -G nor -F option is not
+ specified: function_graph or function.
-v::
--verbose=::
@@ -50,33 +51,35 @@ OPTIONS
-T::
--trace-funcs=::
- Only trace functions given by the argument. Multiple functions
- can be given by using this option more than once. The function
- argument also can be a glob pattern. It will be passed to
- 'set_ftrace_filter' in tracefs.
+ Select function tracer and set function filter on the given
+ function (or a glob pattern). Multiple functions can be given
+ by using this option more than once. The function argument also
+ can be a glob pattern. It will be passed to 'set_ftrace_filter'
+ in tracefs.
-N::
--notrace-funcs=::
- Do not trace functions given by the argument. Like -T option,
- this can be used more than once to specify multiple functions
- (or glob patterns). It will be passed to 'set_ftrace_notrace'
- in tracefs.
+ Select function tracer and do not trace functions given by the
+ argument. Like -T option, this can be used more than once to
+ specify multiple functions (or glob patterns). It will be
+ passed to 'set_ftrace_notrace' in tracefs.
-G::
--graph-funcs=::
- Set graph filter on the given function (or a glob pattern).
- This is useful for the function_graph tracer only and enables
- tracing for functions executed from the given function.
- This can be used more than once to specify multiple functions.
- It will be passed to 'set_graph_function' in tracefs.
+ Select function_graph tracer and set graph filter on the given
+ function (or a glob pattern). This is useful to trace for
+ functions executed from the given function. This can be used more
+ than once to specify multiple functions. It will be passed to
+ 'set_graph_function' in tracefs.
-g::
--nograph-funcs=::
- Set graph notrace filter on the given function (or a glob pattern).
- Like -G option, this is useful for the function_graph tracer only
- and disables tracing for function executed from the given function.
- This can be used more than once to specify multiple functions.
- It will be passed to 'set_graph_notrace' in tracefs.
+ Select function_graph tracer and set graph notrace filter on the
+ given function (or a glob pattern). Like -G option, this is useful
+ for the function_graph tracer only and disables tracing for function
+ executed from the given function. This can be used more than once to
+ specify multiple functions. It will be passed to 'set_graph_notrace'
+ in tracefs.
-D::
--graph-depth=::
diff --git a/tools/perf/builtin-ftrace.c b/tools/perf/builtin-ftrace.c
index 2bfc1b0db536..048a11192b59 100644
--- a/tools/perf/builtin-ftrace.c
+++ b/tools/perf/builtin-ftrace.c
@@ -455,6 +455,23 @@ static void delete_filter_func(struct list_head *head)
}
}
+static void select_tracer(struct perf_ftrace *ftrace)
+{
+ bool graph = !list_empty(&ftrace->graph_funcs) ||
+ !list_empty(&ftrace->nograph_funcs);
+ bool func = !list_empty(&ftrace->filters) ||
+ !list_empty(&ftrace->notrace);
+
+ /* The function_graph has priority over function tracer. */
+ if (graph)
+ ftrace->tracer = "function_graph";
+ else if (func)
+ ftrace->tracer = "function";
+ /* Otherwise, the default tracer is used. */
+
+ pr_debug("%s tracer is used\n", ftrace->tracer);
+}
+
int cmd_ftrace(int argc, const char **argv)
{
int ret;
@@ -479,11 +496,13 @@ int cmd_ftrace(int argc, const char **argv)
OPT_STRING('C', "cpu", &ftrace.target.cpu_list, "cpu",
"list of cpus to monitor"),
OPT_CALLBACK('T', "trace-funcs", &ftrace.filters, "func",
- "trace given functions only", parse_filter_func),
+ "trace given functions using function tracer",
+ parse_filter_func),
OPT_CALLBACK('N', "notrace-funcs", &ftrace.notrace, "func",
"do not trace given functions", parse_filter_func),
OPT_CALLBACK('G', "graph-funcs", &ftrace.graph_funcs, "func",
- "Set graph filter on given functions", parse_filter_func),
+ "trace given functions using function_graph tracer",
+ parse_filter_func),
OPT_CALLBACK('g', "nograph-funcs", &ftrace.nograph_funcs, "func",
"Set nograph filter on given functions",
parse_filter_func),
OPT_INTEGER('D', "graph-depth", &ftrace.graph_depth,
@@ -505,6 +524,8 @@ int cmd_ftrace(int argc, const char **argv)
if (!argc && target__none(&ftrace.target))
ftrace.target.system_wide = true;
+ select_tracer(&ftrace);
+
ret = target__validate(&ftrace.target);
if (ret) {
char errbuf[512];
--
2.25.1
