lttng_channel_attr Struct Reference

Attributes of an event record channel summary. More...

#include <channel.h>

Data Fields
unsigned int	live_timer_interval
	Live timer period (µs), if applicable.
uint64_t	num_subbuf
	Sub-buffer count.
enum lttng_event_output	output
	Output type (Linux kernel event record channel).
int	overwrite
	Event record loss mode.
unsigned int	read_timer_interval
	Read timer period (µs).
uint64_t	subbuf_size
	Sub-buffer size (bytes).
unsigned int	switch_timer_interval
	Switch timer period (µs), if applicable.
uint64_t	tracefile_count
	Maximum trace file count, or 0 for unlimited.
uint64_t	tracefile_size
	Maximum trace file size (bytes), or 0 for unlimited.

Detailed Description

Attributes of an event record channel summary.

The lttng_channel::attr member is an instance of such a structure.

lttng_channel_set_default_attr() sets the members of such a structure to their default values given a specific tracing domain summary.

A valid lttng_channel_attr structure satisfies the following constraints:

Member	Constraints
lttng_channel_attr::overwrite	0, 1, or -1
lttng_channel_attr::subbuf_size	Greater than 0 Power of two
lttng_channel_attr::num_subbuf	Greater than 0 Power of two

Field Documentation

live_timer_interval

unsigned int lttng_channel_attr::live_timer_interval

Live timer period (µs), if applicable.

You may not set this member: use the live_timer_period parameter of lttng_session_descriptor_live_network_create() when you create the descriptor of a live recording session to contain the event record channel to create.

Only available if the recording session which owns this event record channel is in live mode.

overwrite

int lttng_channel_attr::overwrite

Event record loss mode.

One of:

0

The event record loss mode of the event record channel is discard.

1

The event record loss mode of the event record channel is overwrite.

-1

The event record loss mode of the event record channel is the default value of its recording session:

Snapshot mode

Overwrite mode

Other modes

Discard mode

switch_timer_interval

unsigned int lttng_channel_attr::switch_timer_interval

Switch timer period (µs), if applicable.

Only available if the recording session which owns this event record channel is not in live mode.