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    SubjectRe: [PATCH v9 14/22] tracing: Add hist trigger 'hex' modifier for displaying numeric fields
    Hi Tom,

    On Thu, Jul 16, 2015 at 12:22:47PM -0500, Tom Zanussi wrote:
    > 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
    >
    > Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
    > ---
    > kernel/trace/trace.c | 5 +++-
    > kernel/trace/trace_events_hist.c | 49 +++++++++++++++++++++++++++++++++++++---
    > 2 files changed, 50 insertions(+), 4 deletions(-)
    >
    > diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
    > index 27daa28..14f9472 100644
    > --- a/kernel/trace/trace.c
    > +++ b/kernel/trace/trace.c
    > @@ -3810,7 +3810,10 @@ static const char readme_msg[] =
    > "\t entry is a simple list of the keys and values comprising the\n"
    > "\t entry; keys are printed first and are delineated by curly\n"
    > "\t braces, and are followed by the set of value fields for the\n"
    > - "\t entry. Numeric fields are displayed as base-10 integers.\n"
    > + "\t entry. By default, numeric fields are displayed as base-10\n"
    > + "\t integers. This can be modified by appending any of the\n"
    > + "\t following modifiers to the field name:\n\n"
    > + "\t .hex display a number as a hex value\n\n"
    > "\t By default, the size of the hash table is 2048 entries. The\n"
    > "\t 'size' param can be used to specify more or fewer than that.\n"
    > "\t The units are in terms of hashtable entries - if a run uses\n"
    > diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
    > index d8259fe..9cc38ee 100644
    > --- a/kernel/trace/trace_events_hist.c
    > +++ b/kernel/trace/trace_events_hist.c
    > @@ -72,6 +72,7 @@ enum hist_field_flags {
    > HIST_FIELD_HITCOUNT = 1,
    > HIST_FIELD_KEY = 2,
    > HIST_FIELD_STRING = 4,
    > + HIST_FIELD_HEX = 8,
    > };
    >
    > struct hist_trigger_attrs {
    > @@ -284,9 +285,20 @@ 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;
    >
    > - field = trace_find_event_field(file->event_call, field_str);
    > + field_name = strsep(&field_str, ".");
    > + if (field_str) {
    > + if (!strcmp(field_str, "hex"))
    > + flags |= HIST_FIELD_HEX;
    > + else {
    > + ret = -EINVAL;
    > + goto out;
    > + }
    > + }
    > +
    > + field = trace_find_event_field(file->event_call, field_name);
    > if (!field) {
    > ret = -EINVAL;
    > goto out;
    > @@ -349,11 +361,22 @@ 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;
    >
    > flags |= HIST_FIELD_KEY;
    >
    > - field = trace_find_event_field(file->event_call, field_str);
    > + field_name = strsep(&field_str, ".");
    > + if (field_str) {
    > + if (!strcmp(field_str, "hex"))
    > + flags |= HIST_FIELD_HEX;
    > + else {
    > + ret = -EINVAL;
    > + goto out;
    > + }
    > + }
    > +
    > + field = trace_find_event_field(file->event_call, field_name);
    > if (!field) {
    > ret = -EINVAL;
    > goto out;
    > @@ -688,7 +711,11 @@ hist_trigger_entry_print(struct seq_file *m,
    > if (i > hist_data->n_vals)
    > seq_puts(m, ", ");
    >
    > - if (key_field->flags & HIST_FIELD_STRING) {
    > + if (key_field->flags & HIST_FIELD_HEX) {
    > + uval = *(u64 *)(key + key_field->offset);
    > + seq_printf(m, "%s: %llx",
    > + key_field->field->name, uval);
    > + } else if (key_field->flags & HIST_FIELD_STRING) {
    > seq_printf(m, "%s: %-35s", key_field->field->name,
    > (char *)(key + key_field->offset));
    > } else {

    It seems the '.hex' modifier only affects key fields' output..

    Thanks,
    Namhyung


    > @@ -791,9 +818,25 @@ 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_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,
    > --
    > 1.9.3
    >


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