[lttng-dev] [Patch LTTng-ust 1/7] Add or update data structures to support CTF named metadata
Mathieu Desnoyers
mathieu.desnoyers at efficios.com
Mon Feb 3 10:31:12 EST 2014
----- Original Message -----
> From: "Geneviève Bastien" <gbastien at versatic.net>
> To: "Mathieu Desnoyers" <mathieu.desnoyers at efficios.com>, "Geneviève Bastien" <gbastien+lttng at versatic.net>
> Cc: lttng-dev at lists.lttng.org
> Sent: Friday, January 31, 2014 3:27:50 PM
> Subject: Re: [lttng-dev] [Patch LTTng-ust 1/7] Add or update data structures to support CTF named metadata
>
> Thanks for reviewing all those patches! I'll make the changes soon when
> the naming of this concept is settled (see Stefan's email). "Global
> types" sounds good.
OK. Replied in a separate email for this one.
>
> Only thing where answer is needed inline below.
>
> On 14-01-30 06:06 PM, Mathieu Desnoyers wrote:
> > ----- Original Message -----
> >> From: "Geneviève Bastien" <gbastien+lttng at versatic.net>
> >> To: lttng-dev at lists.lttng.org
> >> Sent: Friday, January 24, 2014 3:04:39 PM
> >> Subject: [lttng-dev] [Patch LTTng-ust 1/7] Add or update data structures
> >> to support CTF named metadata
> >>
> >> The structures match those in LTTng-tools to support named metadata in
> >> general
> >> and CTF enumerations in particular.
> >>
> >> Signed-off-by: Geneviève Bastien <gbastien+lttng at versatic.net>
> >> ---
> >> include/lttng/ust-ctl.h | 36 +++++++++++++++++++++++++++++++++++-
> >> include/lttng/ust-events.h | 20 +++++++++++++++++++-
> >> 2 files changed, 54 insertions(+), 2 deletions(-)
> >>
> >> diff --git a/include/lttng/ust-ctl.h b/include/lttng/ust-ctl.h
> >> index 40e831e..29c89fe 100644
> >> --- a/include/lttng/ust-ctl.h
> >> +++ b/include/lttng/ust-ctl.h
> >> @@ -295,13 +295,23 @@ struct ustctl_float_type {
> >> char padding[USTCTL_UST_FLOAT_TYPE_PADDING];
> >> } LTTNG_PACKED;
> >>
> >> -#define USTCTL_UST_BASIC_TYPE_PADDING 296
> >> +#define USTCTL_UST_ENUM_ENTRY_PADDING 296
> >> +struct ustctl_enum_entry {
> >> + unsigned long long start, end; /* start and end are inclusive */
> >> + char string[LTTNG_UST_SYM_NAME_LEN];
> >> + char padding[USTCTL_UST_ENUM_ENTRY_PADDING];
> >> +};
> >> +
> >> +#define USTCTL_UST_BASIC_TYPE_PADDING 40
> >> union _ustctl_basic_type {
> >> struct ustctl_integer_type integer;
> >> struct {
> >> enum ustctl_string_encodings encoding;
> >> } string;
> >> struct ustctl_float_type _float;
> >> + struct {
> >> + char name[LTTNG_UST_SYM_NAME_LEN];
> >> + } enumeration;
> >> char padding[USTCTL_UST_BASIC_TYPE_PADDING];
> >> } LTTNG_PACKED;
> >>
> >> @@ -329,6 +339,30 @@ struct ustctl_type {
> >> } u;
> >> } LTTNG_PACKED;
> >>
> >> +#define USTCTL_UST_ENUM_TYPE_PADDING 296
> >> +struct ustctl_enum {
> >> + char name[LTTNG_UST_SYM_NAME_LEN];
> >> + struct ustctl_integer_type container_type;
> >> + struct ustctl_enum_entry *entries;
> >> + unsigned int len;
> >> + char padding[USTCTL_UST_ENUM_TYPE_PADDING];
> >> +} LTTNG_PACKED;
> >> +
> >> +/* CTF Metadata types for named metadata described outside event
> >> descriptions */
> >> +enum ustctl_metadata_types {
> >> + ustctl_mtype_enum,
> >> + NR_USTCTL_METADATA_TYPES,
> >> +};
> >> +
> >> +#define USTCTL_UST_NAMED_METADATA_PADDING 640
> >> +struct ustctl_named_metadata {
> >> + enum ustctl_metadata_types mtype;
> > OK to use the enumeration, but define this mtype field as a fixed-size
> > field (e.g. int32_t). (yes, I did the mistake to use enums in the ABI
> > in the past). Currently, compilers use 32-bit int typically, but they
> > have some freedom in the choice of the backing type.
> >
> >> + union {
> >> + struct ustctl_enum ctf_enum;
> >> + char padding[USTCTL_UST_NAMED_METADATA_PADDING];
> >> + } u;
> >> +};
> >> +
> >> #define USTCTL_UST_FIELD_PADDING 28
> >> struct ustctl_field {
> >> char name[LTTNG_UST_SYM_NAME_LEN];
> >> diff --git a/include/lttng/ust-events.h b/include/lttng/ust-events.h
> >> index d93c912..260b221 100644
> >> --- a/include/lttng/ust-events.h
> >> +++ b/include/lttng/ust-events.h
> >> @@ -89,6 +89,12 @@ enum lttng_string_encodings {
> >> NR_STRING_ENCODINGS,
> >> };
> >>
> >> +/* CTF Metadata types for named metadata described outside event
> >> descriptions */
> >> +enum lttng_metadata_types {
> >> + mtype_enum,
> >> + NR_METADATA_TYPES,
> >> +};
> >> +
> >> #define LTTNG_UST_ENUM_ENTRY_PADDING 16
> >> struct lttng_enum_entry {
> >> unsigned long long start, end; /* start and end are inclusive */
> >> @@ -204,12 +210,22 @@ struct lttng_type {
> >> #define LTTNG_UST_ENUM_TYPE_PADDING 24
> >> struct lttng_enum {
> >> const char *name;
> >> - struct lttng_type container_type;
> >> + struct lttng_integer_type container_type;
> > doing this change assumes that lttng_enum was never used in lttng-ust, is
> > that true ?
> Are you asking me or the list? I haven't seen any reference to it and
> you told me on IRC that [you thought] it hadn't been used anywhere ever.
> But I don't know about the past of UST... For more security, maybe I
> should just add a new field at the end of this struct?
I think it should be safe to assume that nobody used it, since it's not
supported neither at the instrumentation API level, nor used by lttng-ust,
nor written into the CTF metadata by lttng-sessiond. You might want to
document this assumption in the patch changelog though.
Thanks,
Mathieu
>
> Thanks,
>
> Geneviève
> >
> > Thanks,
> >
> > Mathieu
> >
> >> const struct lttng_enum_entry *entries;
> >> unsigned int len;
> >> char padding[LTTNG_UST_ENUM_TYPE_PADDING];
> >> };
> >>
> >> +#define LTTNG_UST_NAMED_METADATA_PADDING 60
> >> +struct lttng_named_metadata {
> >> + enum lttng_metadata_types mtype;
> >> + unsigned int nowrite; /* inherited from the field using it */
> >> + union {
> >> + const struct lttng_enum *ctf_enum;
> >> + char padding[LTTNG_UST_NAMED_METADATA_PADDING];
> >> + } u;
> >> +};
> >> +
> >> /*
> >> * Event field description
> >> *
> >> @@ -267,6 +283,8 @@ struct lttng_event_desc {
> >> union {
> >> struct {
> >> const char **model_emf_uri;
> >> + unsigned int nr_metadata;
> >> + const struct lttng_named_metadata *named_metadata;
> >> } ext;
> >> char padding[LTTNG_UST_EVENT_DESC_PADDING];
> >> } u;
> >> --
> >> 1.8.5.3
> >>
> >>
> >> _______________________________________________
> >> lttng-dev mailing list
> >> lttng-dev at lists.lttng.org
> >> http://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev
> >>
>
>
--
Mathieu Desnoyers
EfficiOS Inc.
http://www.efficios.com
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