tools lib traceevent: Add filter on task CPU id

Add a 'CPU' special field to allow the filter in trace-cmd report to
filter on the task's CPU.

By adding a special field 'CPU' (all caps) the user can now filter out
tasks based on which CPU they are on. This is useful when filtering out
(or in) a bunch of threads.

  -F 'CPU == 0'

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: http://lkml.kernel.org/r/20160712093306.5b058103@gandalf.local.home
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/lib/traceevent/parse-filter.c b/tools/lib/traceevent/parse-filter.c
index 88cccea..7c214ce 100644 (file)
--- a/tools/lib/traceevent/parse-filter.c
+++ b/tools/lib/traceevent/parse-filter.c
@@ -28,11 +28,16 @@
 #include "event-utils.h"
 
 #define COMM "COMM"
+#define CPU "CPU"
 
 static struct format_field comm = {
        .name = "COMM",
 };
 
+static struct format_field cpu = {
+       .name = "CPU",
+};
+
 struct event_list {
        struct event_list       *next;
        struct event_format     *event;
@@ -382,14 +387,17 @@ create_arg_item(struct event_format *event, const char *token,
                /* Consider this a field */
                field = pevent_find_any_field(event, token);
                if (!field) {
-                       if (strcmp(token, COMM) != 0) {
+                       /* If token is 'COMM' or 'CPU' then it is special */
+                       if (strcmp(token, COMM) == 0) {
+                               field = &comm;
+                       } else if (strcmp(token, CPU) == 0) {
+                               field = &cpu;
+                       } else {
                                /* not a field, Make it false */
                                arg->type = FILTER_ARG_BOOLEAN;
                                arg->boolean.value = FILTER_FALSE;
                                break;
                        }
-                       /* If token is 'COMM' then it is special */
-                       field = &comm;
                }
                arg->type = FILTER_ARG_FIELD;
                arg->field.field = field;
@@ -1718,6 +1726,10 @@ get_value(struct event_format *event,
                return (unsigned long)name;
        }
 
+       /* Handle our dummy "cpu" field */
+       if (field == &cpu)
+               return record->cpu;
+
        pevent_read_number_field(field, record->data, &val);
 
        if (!(field->flags & FIELD_IS_SIGNED))