perf tools: Add --debug optionto set debug variable

Adding --debug option as a way to setup debug variables.  Starting with
support for verbose, more will come.

It's possible to use it now with report command:
  $ perf --debug verbose   ...
  $ perf --debug verbose=2 ...

I'll need this support to add separated debug variable for ordered
events change in order to separate debug output out of standard verbose
stream.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20140717105500.GG516@krava.redhat.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 44 insertions, 0 deletions

diff --git a/tools/perf/util/debug.c b/tools/perf/util/debug.c
index c208d6f56e63..71d419362634 100644
--- a/tools/perf/util/debug.c
+++ b/tools/perf/util/debug.c
@@ -105,3 +105,47 @@ void trace_event(union perf_event *event)
         }
         printf(".\n");
 }
+
+static struct debug_variable {
+        const char *name;
+        int *ptr;
+} debug_variables[] = {
+        { .name = "verbose", .ptr = &verbose },
+        { .name = NULL, }
+};
+
+int perf_debug_option(const char *str)
+{
+        struct debug_variable *var = &debug_variables[0];
+        char *vstr, *s = strdup(str);
+        int v = 1;
+
+        vstr = strchr(s, '=');
+        if (vstr)
+                *vstr++ = 0;
+
+        while (var->name) {
+                if (!strcmp(s, var->name))
+                        break;
+                var++;
+        }
+
+        if (!var->name) {
+                pr_err("Unknown debug variable name '%s'\n", s);
+                free(s);
+                return -1;
+        }
+
+        if (vstr) {
+                v = atoi(vstr);
+                /*
+                 * Allow only values in range (0, 10),
+                 * otherwise set 0.
+                 */
+                v = (v < 0) || (v > 10) ? 0 : v;
+        }
+
+        *var->ptr = v;
+        free(s);
+        return 0;
+}