On Thu, 9 Dec 2021 18:38:15 +0200
"Yordan Karadzhov (VMware)" <y.karadz@xxxxxxxxx> wrote:
> The following APIs are added:
> int tracefs_synth_echo_fmt(struct trace_seq *, struct tracefs_synth *)
> const char *tracefs_synth_show_event(struct tracefs_synth *)
> const char *tracefs_synth_show_start_hist(struct tracefs_synth *)
> const char *tracefs_synth_show_end_hist(struct tracefs_synth *)
>
> The new APIs can be useful in the case whene the user wants to
"where"
> check what exactly gets passed to the kernel as definition of
> a synth event.
>
> Signed-off-by: Yordan Karadzhov (VMware) <y.karadz@xxxxxxxxx>
> ---
> Documentation/libtracefs-synth2.txt | 23 ++++++-
> include/tracefs.h | 5 ++
> src/tracefs-hist.c | 94 +++++++++++++++++++++++------
> 3 files changed, 102 insertions(+), 20 deletions(-)
>
> diff --git a/Documentation/libtracefs-synth2.txt b/Documentation/libtracefs-synth2.txt
> index 569819a..e557bc9 100644
> --- a/Documentation/libtracefs-synth2.txt
> +++ b/Documentation/libtracefs-synth2.txt
> @@ -5,7 +5,8 @@ NAME
> ----
> tracefs_synth_create, tracefs_synth_destroy, tracefs_synth_echo_cmd, tracefs_synth_complete,
> tracefs_synth_get_start_hist, tracefs_synth_trace, tracefs_synth_snapshot,
> -tracefs_synth_get_name - Creation of synthetic events
> +tracefs_synth_get_name, tracefs_synth_echo_fmt, tracefs_synth_show_event,
> +tracefs_synth_show_start_hist, tracefs_synth_show_end_hist - Creation of synthetic events
>
> SYNOPSIS
> --------
> @@ -27,6 +28,11 @@ int tracefs_synth_save(struct tracefs_synth pass:[*]synth,
> enum tracefs_synth_handler type, const char pass:[*]var,
> char pass:[**]save_fields);
> const char *tracefs_synth_get_name(struct tracefs_synth pass:[*]synth);
> +int tracefs_synth_echo_fmt(struct trace_seq pass:[*]seq, struct tracefs_synth pass:[*]synth);
> +const char *tracefs_synth_show_event(struct tracefs_synth pass:[*]synth);
> +const char *tracefs_synth_show_start_hist(struct tracefs_synth pass:[*]synth);
> +const char *tracefs_synth_show_end_hist(struct tracefs_synth pass:[*]synth);
> +
> --
>
> DESCRIPTION
> @@ -93,9 +99,22 @@ _var_ changes. _var_ must be one of the _name_ elements used in *tracefs_synth_a
> The returned string belongs to the synth event object and is freed with the event
> by *tracefs_synth_free*().
>
> +*tracefs_synth_show_event*() returns the format of the dynamic event used by the synthetic
> +event or NULL on error. The returned string belongs to the synth event object and is freed
> +with the event by *tracefs_synth_free*().
> +
> +*tracefs_synth_show_start_hist*() returns the format of the start histogram used by the
> +synthetic event or NULL on error. The returned string belongs to the synth event object
> +and is freed with the event by *tracefs_synth_free*().
> +
> +*tracefs_synth_show_end_hist*() returns the format of the end histogram used by the
> +synthetic event or NULL on error. The returned string belongs to the synth event object
> +and is freed with the event by *tracefs_synth_free*().
> +
> RETURN VALUE
> ------------
> -*tracefs_synth_get_name*() returns a string owned by the synth event object.
> +*tracefs_synth_get_name*(), *tracefs_synth_show_event*(), *tracefs_synth_show_start_hist*()
> +and *tracefs_synth_show_end_hist*() return a string owned by the synth event object.
>
> All other functions return zero on success or -1 on error.
>
> diff --git a/include/tracefs.h b/include/tracefs.h
> index 967690f..b772f5a 100644
> --- a/include/tracefs.h
> +++ b/include/tracefs.h
> @@ -250,6 +250,7 @@ enum tracefs_dynevent_type {
> TRACEFS_DYNEVENT_SYNTH = 1 << 5,
> TRACEFS_DYNEVENT_MAX = 1 << 6,
> };
> +
> int tracefs_dynevent_create(struct tracefs_dynevent *devent);
> int tracefs_dynevent_destroy(struct tracefs_dynevent *devent, bool force);
> int tracefs_dynevent_destroy_all(unsigned int types, bool force);
> @@ -550,6 +551,10 @@ int tracefs_synth_create(struct tracefs_synth *synth);
> int tracefs_synth_destroy(struct tracefs_synth *synth);
> void tracefs_synth_free(struct tracefs_synth *synth);
> int tracefs_synth_echo_cmd(struct trace_seq *seq, struct tracefs_synth *synth);
> +int tracefs_synth_echo_fmt(struct trace_seq *seq, struct tracefs_synth *synth);
> +const char *tracefs_synth_show_event(struct tracefs_synth *synth);
> +const char *tracefs_synth_show_start_hist(struct tracefs_synth *synth);
> +const char *tracefs_synth_show_end_hist(struct tracefs_synth *synth);
>
> struct tracefs_synth *tracefs_sql(struct tep_handle *tep, const char *name,
> const char *sql_buffer, char **err);
> diff --git a/src/tracefs-hist.c b/src/tracefs-hist.c
> index 6051ecc..f5359a5 100644
> --- a/src/tracefs-hist.c
> +++ b/src/tracefs-hist.c
> @@ -683,6 +683,8 @@ struct tracefs_synth {
> struct action *actions;
> struct action **next_action;
> struct tracefs_dynevent *dyn_event;
> + char *start_hist;
> + char *end_hist;
> char *name;
> char **synthetic_fields;
> char **synthetic_args;
> @@ -737,6 +739,8 @@ void tracefs_synth_free(struct tracefs_synth *synth)
> return;
>
> free(synth->name);
> + free(synth->start_hist);
> + free(synth->end_hist);
> tracefs_list_free(synth->synthetic_fields);
> tracefs_list_free(synth->synthetic_args);
> tracefs_list_free(synth->start_keys);
> @@ -1802,6 +1806,67 @@ static char *create_end_hist(struct tracefs_synth *synth)
> return create_actions(end_hist, synth);
> }
>
> +/*
> + * tracefs_synth_echo_fmt - show the raw format of a synthetic event
> + * @seq: A trace_seq to store the format string
> + * @synth: The synthetic event to read format from
> + *
> + * This shows the raw format that describes the synthetic event, including
> + * the format of the dynamic event and the start / end histograms.
> + *
> + * Returns 0 on succes -1 on error.
> + */
> +int tracefs_synth_echo_fmt(struct trace_seq *seq, struct tracefs_synth *synth)
Sorry to nitpick on the naming again, but perhaps we should call this
tracefs_synth_raw_fmt()
Because saying "echo_fmt" I would think it would include the "echo" command
in the output.
> +{
> + if (!synth->dyn_event)
> + return -1;
> +
> + trace_seq_printf(seq, "%s", synth->dyn_event->format);
> + trace_seq_printf(seq, "\n%s", synth->start_hist);
> + trace_seq_printf(seq, "\n%s", synth->end_hist);
Hmm, shouldn't this end with a \n? Or is it to allow quoting?
-- Steve
> +
> + return 0;
> +}
> +
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