Hi Jiri,
I found that only this patch is not enough. When converting such tracepoints,
it uses add_tracepoint_fields_values(..., struct format_field *fields ...),
and fields->name is still the original one.
If 'struct format_field' has a field like 'dup_name' we can make things simpler.
However, struct format_field is part of traceevent, not only used by perf.
I have no enough time to think on it. Jiri, could you please give me some hints
so I can implement another patch tomorrow?
Thank you.
On 2015/1/21 11:23, Wang Nan wrote:
> Some parameters of syscall tracepoints named as 'nr', 'event', etc.
> When dealing with them, perf convert to ctf meets some problem:
>
> 1. If a parameter with name 'nr', it will duplicate syscall's
> common field 'nr'. One such syscall is io_submit().
>
> 2. If a parameter with name 'event', it is denied to be inserted
> because 'event' is a babeltrace keywork. One such syscall is
> epoll_ctl.
>
> This patch appends '_dupl_X' suffix to avoid problem 1, prepend a '_'
> prefix to avoid problem 2.
>
> Signed-off-by: Wang Nan <wangn...@huawei.com>
> ---
> tools/perf/util/data-convert-bt.c | 65
> ++++++++++++++++++++++++++++++++++++---
> 1 file changed, 61 insertions(+), 4 deletions(-)
>
> diff --git a/tools/perf/util/data-convert-bt.c
> b/tools/perf/util/data-convert-bt.c
> index ddecce8..b0a042d 100644
> --- a/tools/perf/util/data-convert-bt.c
> +++ b/tools/perf/util/data-convert-bt.c
> @@ -567,6 +567,38 @@ static int process_sample_event(struct perf_tool *tool,
> return cs ? 0 : -1;
> }
>
> +/* If dup < 0, add a prefix. Else, add _dupl_X suffix. */
> +static char *change_name(char *name, char *orig_name, int dup)
> +{
> + char *new_name = NULL;
> + size_t len;
> +
> + if (!name)
> + name = orig_name;
> +
> + if (dup >= 10)
> + goto out;
> +
> + if (dup < 0)
> + len = strlen(name) + sizeof("_");
> + else
> + len = strlen(orig_name) + sizeof("_dupl_X");
> +
> + new_name = malloc(len);
> + if (!new_name)
> + goto out;
> +
> + if (dup < 0)
> + snprintf(new_name, len, "_%s", name);
> + else
> + snprintf(new_name, len, "%s_dupl_%d", orig_name, dup);
> +
> +out:
> + if (name != orig_name)
> + free(name);
> + return new_name;
> +}
> +
> static int add_tracepoint_fields_types(struct ctf_writer *cw,
> struct format_field *fields,
> struct bt_ctf_event_class *event_class)
> @@ -577,6 +609,9 @@ static int add_tracepoint_fields_types(struct ctf_writer
> *cw,
> for (field = fields; field; field = field->next) {
> struct bt_ctf_field_type *type;
> unsigned long flags = field->flags;
> + struct bt_ctf_field_type *f = NULL;
> + char *name;
> + int dup = 1;
>
> pr2(" field '%s'\n", field->name);
>
> @@ -595,14 +630,36 @@ static int add_tracepoint_fields_types(struct
> ctf_writer *cw,
> if (flags & FIELD_IS_ARRAY)
> type = bt_ctf_field_type_array_create(type,
> field->arraylen);
>
> - ret = bt_ctf_event_class_add_field(event_class, type,
> - field->name);
> + /* Check name duplication */
> + name = field->name;
> + while (f = bt_ctf_event_class_get_field_by_name(event_class,
> name)) {
> + bt_ctf_field_type_put(f);
> + name = change_name(name, field->name, dup++);
> + if (!name) {
> + pr_err("Failed to create dup name for '%s'\n",
> field->name);
> + return -1;
> + }
> + }
> +
> + ret = bt_ctf_event_class_add_field(event_class, type, name);
> + /* if failed, we may hit a keywork. try again with a '_' prefix
> */
> + if (ret) {
> + name = change_name(name, field->name, -1);
> + if (!name) {
> + pr_err("Failed to alloc name for '_%s'\n",
> field->name);
> + return -1;
> + }
> + ret = bt_ctf_event_class_add_field(event_class, type,
> name);
> + }
> + if (name != field->name)
> + free(name);
>
> if (flags & FIELD_IS_ARRAY)
> bt_ctf_field_type_put(type);
>
> if (ret) {
> - pr_err("Failed to add field '%s\n", field->name);
> + pr_err("Failed to add field '%s': %d\n",
> + field->name, ret);
> return -1;
> }
> }
> @@ -646,7 +703,7 @@ static int add_generic_types(struct ctf_writer *cw,
> struct perf_evsel *evsel,
> do { \
> pr2(" field '%s'\n", n); \
> if (bt_ctf_event_class_add_field(cl, t, n)) { \
> - pr_err("Failed to add field '%s;\n", n); \
> + pr_err("Failed to add field '%s';\n", n); \
> return -1; \
> } \
> } while (0)
>
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