tracing: Add hist trigger 'hex' modifier for displaying numeric fields

Allow users to have numeric fields displayed as hex values in the
output by appending '.hex' to field names:

   # echo hist:keys=aaa,bbb.hex:vals=ccc.hex ... \
              [ if filter] > event/trigger

Link: http://lkml.kernel.org/r/67bd431edda2af5798d7694818f7e8d71b6b3463.1457029949.git.tom.zanussi@linux.intel.com
Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Tested-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Reviewed-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 4097cd3763f7fed5af981b4e135dd9a99140440f..2eb2eafbe7f54d0d984b48a8733baed5f8d53274 100644 (file)
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -3852,7 +3852,10 @@ static const char readme_msg[] =
        "\t    used to specify more or fewer than the default 2048 entries\n"
        "\t    for the hashtable size.\n\n"
        "\t    Reading the 'hist' file for the event will dump the hash\n"
-       "\t    table in its entirety to stdout.\n\n"
+       "\t    table in its entirety to stdout.  The default format used to\n"
+       "\t    display a given field can be modified by appending any of the\n"
+       "\t    following modifiers to the field name, as applicable:\n\n"
+       "\t            .hex        display a number as a hex value\n\n"
        "\t    The 'pause' parameter can be used to pause an existing hist\n"
        "\t    trigger or to start a hist trigger but not log any events\n"
        "\t    until told to do so.  'continue' can be used to start or\n"

diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
index 83cb25e067ad21b9c4f379a9908bcbb6c5fe7ada..8e49eeef8867c053864995263f0d66684230ed98 100644 (file)
--- a/kernel/trace/trace_events_hist.c
+++ b/kernel/trace/trace_events_hist.c
@@ -80,6 +80,7 @@ enum hist_field_flags {
        HIST_FIELD_FL_HITCOUNT  = 1,
        HIST_FIELD_FL_KEY       = 2,
        HIST_FIELD_FL_STRING    = 4,
+       HIST_FIELD_FL_HEX       = 8,
 };
 
 struct hist_trigger_attrs {
@@ -303,11 +304,23 @@ static int create_val_field(struct hist_trigger_data *hist_data,
 {
        struct ftrace_event_field *field = NULL;
        unsigned long flags = 0;
+       char *field_name;
        int ret = 0;
 
        if (WARN_ON(val_idx >= TRACING_MAP_VALS_MAX))
                return -EINVAL;
-       field = trace_find_event_field(file->event_call, field_str);
+
+       field_name = strsep(&field_str, ".");
+       if (field_str) {
+               if (strcmp(field_str, "hex") == 0)
+                       flags |= HIST_FIELD_FL_HEX;
+               else {
+                       ret = -EINVAL;
+                       goto out;
+               }
+       }
+
+       field = trace_find_event_field(file->event_call, field_name);
        if (!field) {
                ret = -EINVAL;
                goto out;
@@ -372,6 +385,7 @@ static int create_key_field(struct hist_trigger_data *hist_data,
        struct ftrace_event_field *field = NULL;
        unsigned long flags = 0;
        unsigned int key_size;
+       char *field_name;
        int ret = 0;
 
        if (WARN_ON(key_idx >= TRACING_MAP_FIELDS_MAX))
@@ -379,7 +393,17 @@ static int create_key_field(struct hist_trigger_data *hist_data,
 
        flags |= HIST_FIELD_FL_KEY;
 
-       field = trace_find_event_field(file->event_call, field_str);
+       field_name = strsep(&field_str, ".");
+       if (field_str) {
+               if (strcmp(field_str, "hex") == 0)
+                       flags |= HIST_FIELD_FL_HEX;
+               else {
+                       ret = -EINVAL;
+                       goto out;
+               }
+       }
+
+       field = trace_find_event_field(file->event_call, field_name);
        if (!field) {
                ret = -EINVAL;
                goto out;
@@ -713,7 +737,11 @@ hist_trigger_entry_print(struct seq_file *m,
                if (i > hist_data->n_vals)
                        seq_puts(m, ", ");
 
-               if (key_field->flags & HIST_FIELD_FL_STRING) {
+               if (key_field->flags & HIST_FIELD_FL_HEX) {
+                       uval = *(u64 *)(key + key_field->offset);
+                       seq_printf(m, "%s: %llx",
+                                  key_field->field->name, uval);
+               } else if (key_field->flags & HIST_FIELD_FL_STRING) {
                        seq_printf(m, "%s: %-50s", key_field->field->name,
                                   (char *)(key + key_field->offset));
                } else {
@@ -729,9 +757,15 @@ hist_trigger_entry_print(struct seq_file *m,
                   tracing_map_read_sum(elt, HITCOUNT_IDX));
 
        for (i = 1; i < hist_data->n_vals; i++) {
-               seq_printf(m, "  %s: %10llu",
-                          hist_data->fields[i]->field->name,
-                          tracing_map_read_sum(elt, i));
+               if (hist_data->fields[i]->flags & HIST_FIELD_FL_HEX) {
+                       seq_printf(m, "  %s: %10llx",
+                                  hist_data->fields[i]->field->name,
+                                  tracing_map_read_sum(elt, i));
+               } else {
+                       seq_printf(m, "  %s: %10llu",
+                                  hist_data->fields[i]->field->name,
+                                  tracing_map_read_sum(elt, i));
+               }
        }
 
        seq_puts(m, "\n");
@@ -816,9 +850,25 @@ const struct file_operations event_hist_fops = {
        .release = single_release,
 };
 
+static const char *get_hist_field_flags(struct hist_field *hist_field)
+{
+       const char *flags_str = NULL;
+
+       if (hist_field->flags & HIST_FIELD_FL_HEX)
+               flags_str = "hex";
+
+       return flags_str;
+}
+
 static void hist_field_print(struct seq_file *m, struct hist_field *hist_field)
 {
        seq_printf(m, "%s", hist_field->field->name);
+       if (hist_field->flags) {
+               const char *flags_str = get_hist_field_flags(hist_field);
+
+               if (flags_str)
+                       seq_printf(m, ".%s", flags_str);
+       }
 }
 
 static int event_hist_trigger_print(struct seq_file *m,