perf ftrace: Add support for trace option tracing_thresh

This adds an option '--graph-opts thresh' to setup trace duration
threshold for funcgraph tracer.

  $ sudo ./perf ftrace -G '*' --graph-opts thresh=100
   3) ! 184.060 us  |    } /* schedule */
   3) ! 185.600 us  |  } /* exit_to_usermode_loop */
   2) ! 225.989 us  |    } /* schedule_idle */
   2) # 4140.051 us |  } /* do_idle */

Signed-off-by: Changbin Du <changbin.du@gmail.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Link: http://lore.kernel.org/lkml/20200808023141.14227-14-changbin.du@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/Documentation/perf-ftrace.txt b/tools/perf/Documentation/perf-ftrace.txt
index a2056aaf2ece396d360d59ab4a1ac25ac49efba6..6fa927e5971b3fff87c7080fd9e96f2590fdb829 100644 (file)
--- a/tools/perf/Documentation/perf-ftrace.txt
+++ b/tools/perf/Documentation/perf-ftrace.txt
@@ -107,6 +107,7 @@ OPTIONS
          nosleep-time - Measure on-CPU time only for function_graph tracer.
          noirqs       - Ignore functions that happen inside interrupt.
          verbose      - Show process names, PIDs, timestamps, etc.
+         thresh=<n>   - Setup trace duration threshold in microseconds.
 
 SEE ALSO
 --------

diff --git a/tools/perf/builtin-ftrace.c b/tools/perf/builtin-ftrace.c
index 8ee5287bd84aeac1d6f56693f8c9b55378189484..ca61f8b8bbf627dad149d0c4236cec8db5a8c4a1 100644 (file)
--- a/tools/perf/builtin-ftrace.c
+++ b/tools/perf/builtin-ftrace.c
@@ -48,6 +48,7 @@ struct perf_ftrace {
        int                     graph_nosleep_time;
        int                     graph_noirqs;
        int                     graph_verbose;
+       int                     graph_thresh;
 };
 
 struct filter_entry {
@@ -234,6 +235,9 @@ static int reset_tracing_files(struct perf_ftrace *ftrace __maybe_unused)
        if (write_tracing_file("max_graph_depth", "0") < 0)
                return -1;
 
+       if (write_tracing_file("tracing_thresh", "0") < 0)
+               return -1;
+
        reset_tracing_filters();
        reset_tracing_options(ftrace);
        return 0;
@@ -446,6 +450,20 @@ static int set_tracing_funcgraph_verbose(struct perf_ftrace *ftrace)
        return 0;
 }
 
+static int set_tracing_thresh(struct perf_ftrace *ftrace)
+{
+       int ret;
+
+       if (ftrace->graph_thresh == 0)
+               return 0;
+
+       ret = write_tracing_file_int("tracing_thresh", ftrace->graph_thresh);
+       if (ret < 0)
+               return ret;
+
+       return 0;
+}
+
 static int __cmd_ftrace(struct perf_ftrace *ftrace, int argc, const char **argv)
 {
        char *trace_file;
@@ -545,6 +563,11 @@ static int __cmd_ftrace(struct perf_ftrace *ftrace, int argc, const char **argv)
                goto out_reset;
        }
 
+       if (set_tracing_thresh(ftrace) < 0) {
+               pr_err("failed to set tracing thresh\n");
+               goto out_reset;
+       }
+
        if (write_tracing_file("current_tracer", ftrace->tracer) < 0) {
                pr_err("failed to set current_tracer to %s\n", ftrace->tracer);
                goto out_reset;
@@ -727,6 +750,7 @@ static int parse_graph_tracer_opts(const struct option *opt,
                { .name = "nosleep-time",       .value_ptr = &ftrace->graph_nosleep_time },
                { .name = "noirqs",             .value_ptr = &ftrace->graph_noirqs },
                { .name = "verbose",            .value_ptr = &ftrace->graph_verbose },
+               { .name = "thresh",             .value_ptr = &ftrace->graph_thresh },
                { .name = NULL, }
        };
 
@@ -798,7 +822,7 @@ int cmd_ftrace(int argc, const char **argv)
        OPT_INTEGER('D', "graph-depth", &ftrace.graph_depth,
                    "Max depth for function graph tracer"),
        OPT_CALLBACK(0, "graph-opts", &ftrace, "options",
-                    "graph tracer options, available options: nosleep-time,noirqs,verbose",
+                    "graph tracer options, available options: nosleep-time,noirqs,verbose,thresh=<n>",
                     parse_graph_tracer_opts),
        OPT_CALLBACK('m', "buffer-size", &ftrace.percpu_buffer_size, "size",
                     "size of per cpu buffer", parse_buffer_size),