Collaboration diagram for Data stream infos:

Data Structures
struct	lttng_data_stream_info
	Data stream info (opaque type). More...

struct	lttng_data_stream_info_set
	Data stream info set (opaque type). More...

struct	lttng_data_stream_info_sets
	Set of data stream info sets (opaque type). More...

Enumerations
enum	lttng_app_bitness { LTTNG_APP_BITNESS_32 , LTTNG_APP_BITNESS_64 }
	Bitness of an instrumented application. More...

enum	lttng_data_stream_info_status { LTTNG_DATA_STREAM_INFO_STATUS_OK , LTTNG_DATA_STREAM_INFO_STATUS_NONE , LTTNG_DATA_STREAM_INFO_STATUS_ERROR , LTTNG_DATA_STREAM_INFO_STATUS_INVALID_PARAMETER }
	Return type for data stream info functions. More...

Functions
enum lttng_data_stream_info_status	lttng_data_stream_info_get_cpu_id (const struct lttng_data_stream_info stream_info, unsigned int cpu_id)
	Sets `*cpu_id` to the CPU ID of the data stream info `stream_info`.

enum lttng_data_stream_info_status	lttng_data_stream_info_get_memory_usage (const struct lttng_data_stream_info stream_info, uint64_t value)
	Sets `*value` to the current memory usage (bytes) of the data stream info `stream_info`.

enum lttng_data_stream_info_status	lttng_data_stream_info_set_get_app_bitness (const struct lttng_data_stream_info_set set, enum lttng_app_bitness bitness)
	Sets `*bitness` to the application bitness of the data streams of the data stream set `set`.

enum lttng_data_stream_info_status	lttng_data_stream_info_set_get_at_index (const struct lttng_data_stream_info_set set, unsigned int index, const struct lttng_data_stream_info *stream_info)
	Sets `*stream_info` to the data stream info at the index `index` in the data stream info set `set`.

enum lttng_data_stream_info_status	lttng_data_stream_info_set_get_count (const struct lttng_data_stream_info_set set, unsigned int count)
	Sets `*count` to the number of data stream infos in the data stream info set `set`.

enum lttng_data_stream_info_status	lttng_data_stream_info_set_get_pid (const struct lttng_data_stream_info_set set, pid_t pid)
	Sets `*pid` to the process ID of the owner of the data streams of the data stream info set `set`.

enum lttng_data_stream_info_status	lttng_data_stream_info_set_get_uid (const struct lttng_data_stream_info_set set, uid_t uid)
	Sets `*uid` to the Unix user ID of the owner of the data streams of the data stream info set `set`.

void	lttng_data_stream_info_sets_destroy (const struct lttng_data_stream_info_sets *sets)
	Destroys the set of data stream info sets `sets`.

enum lttng_data_stream_info_status	lttng_data_stream_info_sets_get_at_index (const struct lttng_data_stream_info_sets sets, unsigned int index, const struct lttng_data_stream_info_set *set)
	Sets `*set` to the data stream info set at the index `index` in the set of data stream info sets `sets`.

enum lttng_data_stream_info_status	lttng_data_stream_info_sets_get_count (const struct lttng_data_stream_info_sets sets, unsigned int count)
	Sets `*count` to the number of data stream info sets in the set of data stream info sets `sets`.

Detailed Description

A data stream info (lttng_data_stream_info) represents information about a single data stream of a user space channel.

The main purpose of this API is to get the CPU ID (for a per-CPU channel only) and memory usage of the data streams of a channel.

A data stream info set (lttng_data_stream_info_set) contains data stream infos that share common ownership properties (same Unix user ID, process ID, or instrumented application bitness).

A set of data stream info sets (lttng_data_stream_info_sets) groups multiple data stream info sets for a given channel.

To get CPU ID and memory usage of the data streams of a channel:

Retrieve data stream info sets for the channel with lttng_channel_get_data_stream_info_sets().

This function returns a container of snapshots of information about data streams at call time: the returned object tree is immutable.
For each data stream info set (use lttng_data_stream_info_sets_get_at_index() (borrowed) and lttng_data_stream_info_sets_get_count()):
1. Get the ID of its owning Unix user/process and its application bitness with lttng_data_stream_info_set_get_uid(), lttng_data_stream_info_set_get_pid(), and lttng_data_stream_info_set_get_app_bitness().
2. For each data stream info (use lttng_data_stream_info_set_get_at_index() (borrowed) and lttng_data_stream_info_set_get_count()):
  - Get its memory usage and CPU ID with lttng_data_stream_info_get_cpu_id() and lttng_data_stream_info_get_memory_usage().
When you're done with the data stream info sets, destroy them with lttng_data_stream_info_sets_destroy().

Note: The content and availability of memory usage information may vary depending on tracer support.

Enumeration Type Documentation

◆ lttng_app_bitness

enum lttng_app_bitness

Bitness of an instrumented application.

Enumerator
LTTNG_APP_BITNESS_32	32-bit.
LTTNG_APP_BITNESS_64	64-bit.

◆ lttng_data_stream_info_status

enum lttng_data_stream_info_status

Return type for data stream info functions.

Error status enumerators have a negative value.

Enumerator
LTTNG_DATA_STREAM_INFO_STATUS_OK	Success.
LTTNG_DATA_STREAM_INFO_STATUS_NONE	Information not available.
LTTNG_DATA_STREAM_INFO_STATUS_ERROR	Other error.
LTTNG_DATA_STREAM_INFO_STATUS_INVALID_PARAMETER	Unsatisfied precondition.

Function Documentation

◆ lttng_data_stream_info_get_cpu_id()

enum lttng_data_stream_info_status lttng_data_stream_info_get_cpu_id	(	const struct lttng_data_stream_info *	stream_info,
		unsigned int *	cpu_id
	)

extern

Sets *cpu_id to the CPU ID of the data stream info stream_info.

When a channel uses a per-CPU buffer ownership model, each data stream of the channel is bound to a specific CPU and therefore has a CPU ID. Otherwise, the CPU ID isn't set and this function returns LTTNG_DATA_STREAM_INFO_STATUS_NONE.

Parameters

[in]	stream_info	Data stream information from which to get the CPU ID.
[out]	cpu_id	On success, this function sets `*cpu_id` to the ID of the CPU to which the data stream of `stream_info` is bound.

Return values

LTTNG_DATA_STREAM_INFO_STATUS_OK	Success.
LTTNG_DATA_STREAM_INFO_STATUS_NONE	The data stream of `stream_info` isn't bound to a CPU.
LTTNG_DATA_STREAM_INFO_STATUS_INVALID_PARAMETER	Unsatisfied precondition.

Precondition

stream_info is not NULL.
cpu_id is not NULL.

◆ lttng_data_stream_info_get_memory_usage()

enum lttng_data_stream_info_status lttng_data_stream_info_get_memory_usage	(	const struct lttng_data_stream_info *	stream_info,
		uint64_t *	value
	)

extern

Sets *value to the current memory usage (bytes) of the data stream info stream_info.

Parameters

[in]	stream_info	Data stream information object from which to get the memory usage.
[out]	value	On success, this function sets `*value` to the current memory usage (bytes) of `stream_info`.

Return values

LTTNG_DATA_STREAM_INFO_STATUS_OK	Success.
LTTNG_DATA_STREAM_INFO_STATUS_INVALID_PARAMETER	Unsatisfied precondition.

Precondition

stream_info is not NULL.
value is not NULL.

◆ lttng_data_stream_info_set_get_app_bitness()

enum lttng_data_stream_info_status lttng_data_stream_info_set_get_app_bitness	(	const struct lttng_data_stream_info_set *	set,
		enum lttng_app_bitness *	bitness
	)

extern

Sets *bitness to the application bitness of the data streams of the data stream set set.

Parameters

[in]	set	Data stream set for which to get the application bitness.
[out]	bitness	On success, this function sets `*bitness` to the application bitness of the data streams of `set`.

Return values

LTTNG_DATA_STREAM_INFO_STATUS_OK	Success.
LTTNG_DATA_STREAM_INFO_STATUS_INVALID_PARAMETER	Unsatisfied precondition.

Precondition

set is not NULL.
bitness is not NULL.

◆ lttng_data_stream_info_set_get_at_index()

enum lttng_data_stream_info_status lttng_data_stream_info_set_get_at_index	(	const struct lttng_data_stream_info_set *	set,
		unsigned int	index,
		const struct lttng_data_stream_info **	stream_info
	)

extern

Sets *stream_info to the data stream info at the index index in the data stream info set set.

Parameters

[in] set Data stream info set from which to get the data stream info at the index index.

[in] index Index of the data stream info to get from set.

[out]

stream_info

On success, this function sets *stream_info to the data stream info at the index index in set.

*stream_info remains valid as long as set exists.

Return values

LTTNG_DATA_STREAM_INFO_STATUS_OK	Success.
LTTNG_DATA_STREAM_INFO_STATUS_INVALID_PARAMETER	Unsatisfied precondition.

Precondition

set is not NULL.
index is less than the number of data stream infos in set (as given by lttng_data_stream_info_set_get_count()).
stream_info is not NULL.

◆ lttng_data_stream_info_set_get_count()

enum lttng_data_stream_info_status lttng_data_stream_info_set_get_count	(	const struct lttng_data_stream_info_set *	set,
		unsigned int *	count
	)

extern

Sets *count to the number of data stream infos in the data stream info set set.

Parameters

[in]	set	Set of data stream info of which to get the count.
[out]	count	On success, this function sets `*count` to the number of data stream infos in `set`.

Return values

LTTNG_DATA_STREAM_INFO_STATUS_OK	Success.
LTTNG_DATA_STREAM_INFO_STATUS_INVALID_PARAMETER	Unsatisfied precondition.

Precondition

set is not NULL.
count is not NULL.

See also: lttng_data_stream_info_set_get_at_index() – Get a data stream info from a data stream info set by index.

◆ lttng_data_stream_info_set_get_pid()

enum lttng_data_stream_info_status lttng_data_stream_info_set_get_pid	(	const struct lttng_data_stream_info_set *	set,
		pid_t *	pid
	)

extern

Sets *pid to the process ID of the owner of the data streams of the data stream info set set.

If set represents per-user data streams, then the owner is a Unix user and this function returns LTTNG_DATA_STREAM_INFO_STATUS_NONE.

Parameters

[in]	set	Data stream info set of which to get the ID of the owning process.
[out]	pid	On success, this function sets `*pid` to the ID of the owning process of the data streams of `set`.

Return values

LTTNG_DATA_STREAM_INFO_STATUS_OK	Success.
LTTNG_DATA_STREAM_INFO_STATUS_NONE	`set` isn't owned by a process.
LTTNG_DATA_STREAM_INFO_STATUS_INVALID_PARAMETER	Unsatisfied precondition.

Precondition

set is not NULL.
pid is not NULL.

◆ lttng_data_stream_info_set_get_uid()

enum lttng_data_stream_info_status lttng_data_stream_info_set_get_uid	(	const struct lttng_data_stream_info_set *	set,
		uid_t *	uid
	)

extern

Sets *uid to the Unix user ID of the owner of the data streams of the data stream info set set.

If set represents per-process data streams, then the owner is a process and this function returns LTTNG_DATA_STREAM_INFO_STATUS_NONE.

Parameters

[in]	set	Data stream info set of which to get the ID of the owning Unix user.
[out]	uid	On success, this function sets `*uid` to the ID of the Unix user owning the data streams of `set`.

Return values

LTTNG_DATA_STREAM_INFO_STATUS_OK	Success.
LTTNG_DATA_STREAM_INFO_STATUS_NONE	`set` isn't owned by a Unix user.
LTTNG_DATA_STREAM_INFO_STATUS_INVALID_PARAMETER	Unsatisfied precondition.

Precondition

set is not NULL.
uid is not NULL.

◆ lttng_data_stream_info_sets_destroy()

void lttng_data_stream_info_sets_destroy ( const struct lttng_data_stream_info_sets * sets )

extern

Destroys the set of data stream info sets sets.

Parameters

[in]

sets

Set of data stream info sets to destroy.

May be NULL.

◆ lttng_data_stream_info_sets_get_at_index()

enum lttng_data_stream_info_status lttng_data_stream_info_sets_get_at_index	(	const struct lttng_data_stream_info_sets *	sets,
		unsigned int	index,
		const struct lttng_data_stream_info_set **	set
	)

extern

Sets *set to the data stream info set at the index index in the set of data stream info sets sets.

Parameters

[in] sets Set of data stream info sets from which to get the data stream info set at the index index.

[in] index Index of the data stream info set to get from sets.

[out]

set

On success, this function sets *set to the data stream info set at the index index in sets.

*set remains valid as long as sets exists.

Return values

LTTNG_DATA_STREAM_INFO_STATUS_OK	Success.
LTTNG_DATA_STREAM_INFO_STATUS_INVALID_PARAMETER	Unsatisfied precondition.

Precondition

sets is not NULL.
index is less than the number of data stream info sets in sets (as given by lttng_data_stream_info_sets_get_count()).
set is not NULL.

◆ lttng_data_stream_info_sets_get_count()

enum lttng_data_stream_info_status lttng_data_stream_info_sets_get_count	(	const struct lttng_data_stream_info_sets *	sets,
		unsigned int *	count
	)

extern

Sets *count to the number of data stream info sets in the set of data stream info sets sets.

Parameters

[in]	sets	Set of data stream info sets of which to get the count.
[out]	count	On success, this function sets `*count` to the number of data stream info sets in `sets`.

Return values

LTTNG_DATA_STREAM_INFO_STATUS_OK	Success.
LTTNG_DATA_STREAM_INFO_STATUS_INVALID_PARAMETER	Unsatisfied precondition.

Precondition

sets is not NULL.
count is not NULL.

See also: lttng_data_stream_info_sets_get_at_index() – Get a data stream info set from a set of data stream info sets by index.

Data Structures

Enumerations

Functions

Detailed Description

Enumeration Type Documentation

◆ lttng_app_bitness

◆ lttng_data_stream_info_status

Function Documentation

◆ lttng_data_stream_info_get_cpu_id()

◆ lttng_data_stream_info_get_memory_usage()

◆ lttng_data_stream_info_set_get_app_bitness()

◆ lttng_data_stream_info_set_get_at_index()

◆ lttng_data_stream_info_set_get_count()

◆ lttng_data_stream_info_set_get_pid()

◆ lttng_data_stream_info_set_get_uid()

◆ lttng_data_stream_info_sets_destroy()

◆ lttng_data_stream_info_sets_get_at_index()

◆ lttng_data_stream_info_sets_get_count()