[PATCH] tools lib traceevent: Add filter on task CPU id

From: Steven Rostedt
Date: Tue Jul 12 2016 - 09:33:17 EST



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@xxxxxxxxxxx>
---
tools/lib/traceevent/parse-filter.c | 18 +++++++++++++++---
1 file changed, 15 insertions(+), 3 deletions(-)

diff --git a/tools/lib/traceevent/parse-filter.c b/tools/lib/traceevent/parse-filter.c
index 88cccea3ca99..7c214ceb9386 100644
--- 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))
--
1.9.3