/* * Copyright (C) 2017 - Jérémie Galarneau * * This library is free software; you can redistribute it and/or modify it * under the terms of the GNU Lesser General Public License, version 2.1 only, * as published by the Free Software Foundation. * * This library is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License * for more details. * * You should have received a copy of the GNU Lesser General Public License * along with this library; if not, write to the Free Software Foundation, * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ #ifndef LTTNG_CONDITION_BUFFER_USAGE_H #define LTTNG_CONDITION_BUFFER_USAGE_H #include #include #include #include #ifdef __cplusplus extern "C" { #endif /** * Buffer usage conditions allows an action to be taken whenever a channel's * buffer usage crosses a set threshold. * * These conditions are periodically evaluated against the current buffer * usage statistics. The period at which these conditions are evaluated is * governed by the channels' monitor timer. * * Note that the use of these conditons does not imply any hysteresis-loop * mechanism. For instance, an upper-bound buffer usage condition set to 75% * will fire everytime the buffer usage goes from a value < 75% to a value that * is >= 75%. The evaluation result does not depend on any lower-bound condition * being reached before the condition is evaluated to true again. * * Buffer usage conditions have the following properties: * - the exact name of the session in which the channel to be monitored is * defined, * - the domain of the channel to be monitored, * - the exact name of the channel to be monitored, * - a usage threshold, expressed either in bytes or as a fraction of total * buffer capacity. * * Wildcards, regular expressions or other globbing mechanisms are not supported * in buffer usage condition properties. */ /* * Create a newly allocated lower-bound buffer usage condition. * * A lower-bound buffer usage condition evaluates to true whenever * a buffer's usage _crosses_ the bound that is defined as part of the * condition's properties from high to low. In other words, the condition only * evaluates to true when a buffer's usage transitions from a value higher than * the threshold defined in the condition to a value lower than the threshold * defined in the condition. * * Returns a new condition on success, NULL on failure. This condition must be * destroyed using lttng_condition_destroy(). */ extern struct lttng_condition * lttng_condition_buffer_usage_low_create(void); /* * Create a newly allocated upper-bound buffer usage condition. * * An upper-bound buffer usage condition evaluates to true whenever * a buffer's usage _crosses_ the bound that is defined as part of the * condition's properties from low to high. In other words, the condition only * evaluates to true when a buffer's usage transitions from a value lower than * the threshold defined in the condition to a value higher than the threshold * defined in the condition. * * Returns a new condition on success, NULL on failure. This condition must be * destroyed using lttng_condition_destroy(). */ extern struct lttng_condition * lttng_condition_buffer_usage_high_create(void); /* * Get the buffer usage threshold ratio of a buffer usage condition. * * The buffer usage condition's threshold must have been defined as a ratio in * order for this call to succeed. * * Returns LTTNG_CONDITION_STATUS_OK on success and a ratio contained by the * interval [0.0, 1.0]. LTTNG_CONDITION_STATUS_INVALID is returned if an invalid * parameter is passed, or LTTNG_CONDITION_STATUS_UNSET if a threshold, * expressed as a ratio of total buffer capacity, was not set prior to this * call. */ extern enum lttng_condition_status lttng_condition_buffer_usage_get_threshold_ratio( const struct lttng_condition *condition, double *threshold_ratio); /* * Set the buffer usage threshold ratio of a buffer usage condition. * * The threshold ratio passed must be contained by the interval [0.0, 1.0] and * represents a ratio of the channel's buffer's capacity. Setting a threshold, * either as a ratio or as an absolute size in bytes will override any * previously set threshold. * * Returns LTTNG_CONDITION_STATUS_OK on success, LTTNG_CONDITION_STATUS_INVALID * if invalid paramenters are passed. */ extern enum lttng_condition_status lttng_condition_buffer_usage_set_threshold_ratio( struct lttng_condition *condition, double threshold_ratio); /* * Get the buffer usage threshold of a buffer usage condition. * * The buffer usage condition's threshold must have been defined as an absolute * value expressed in bytes in order for this call to succeed. * * Returns LTTNG_CONDITION_STATUS_OK on success and a threshold expressed in * bytes, LTTNG_CONDITION_STATUS_INVALID if an invalid parameter is passed, or * LTTNG_CONDITION_STATUS_UNSET if a threshold, expressed as an absolute size in * bytes, was not set prior to this call. */ extern enum lttng_condition_status lttng_condition_buffer_usage_get_threshold( const struct lttng_condition *condition, uint64_t *threshold_bytes); /* * Set the buffer usage threshold in bytes of a buffer usage condition. * * Setting a threshold, either as a ratio or as an absolute size in bytes * will override any previously set threshold. * * Returns LTTNG_CONDITION_STATUS_OK on success, LTTNG_CONDITION_STATUS_INVALID * if invalid paramenters are passed. */ extern enum lttng_condition_status lttng_condition_buffer_usage_set_threshold( struct lttng_condition *condition, uint64_t threshold_bytes); /* * Get the session name property of a buffer usage condition. * * The caller does not assume the ownership of the returned session name. The * session name shall only only be used for the duration of the condition's * lifetime, or before a different session name is set. * * Returns LTTNG_CONDITION_STATUS_OK and a pointer to the condition's session * name on success, LTTNG_CONDITION_STATUS_INVALID if an invalid * parameter is passed, or LTTNG_CONDITION_STATUS_UNSET if a session name * was not set prior to this call. */ extern enum lttng_condition_status lttng_condition_buffer_usage_get_session_name( const struct lttng_condition *condition, const char **session_name); /* * Set the session name property of a buffer usage condition. * * The passed session name parameter will be copied to the condition. * * Returns LTTNG_CONDITION_STATUS_OK on success, LTTNG_CONDITION_STATUS_INVALID * if invalid paramenters are passed. */ extern enum lttng_condition_status lttng_condition_buffer_usage_set_session_name( struct lttng_condition *condition, const char *session_name); /* * Get the channel name property of a buffer usage condition. * * The caller does not assume the ownership of the returned channel name. The * channel name shall only only be used for the duration of the condition's * lifetime, or before a different channel name is set. * * Returns LTTNG_CONDITION_STATUS_OK and a pointer to the condition's channel * name on success, LTTNG_CONDITION_STATUS_INVALID if an invalid * parameter is passed, or LTTNG_CONDITION_STATUS_UNSET if a channel name * was not set prior to this call. */ extern enum lttng_condition_status lttng_condition_buffer_usage_get_channel_name( const struct lttng_condition *condition, const char **channel_name); /* * Set the channel name property of a buffer usage condition. * * The passed channel name parameter will be copied to the condition. * * Returns LTTNG_CONDITION_STATUS_OK on success, LTTNG_CONDITION_STATUS_INVALID * if invalid paramenters are passed. */ extern enum lttng_condition_status lttng_condition_buffer_usage_set_channel_name( struct lttng_condition *condition, const char *channel_name); /* * Get the domain type property of a buffer usage condition. * * Returns LTTNG_CONDITION_STATUS_OK and sets the domain type output parameter * on success, LTTNG_CONDITION_STATUS_INVALID if an invalid parameter is passed, * or LTTNG_CONDITION_STATUS_UNSET if a domain type was not set prior to this * call. */ extern enum lttng_condition_status lttng_condition_buffer_usage_get_domain_type( const struct lttng_condition *condition, enum lttng_domain_type *type); /* * Set the domain type property of a buffer usage condition. * * Returns LTTNG_CONDITION_STATUS_OK on success, LTTNG_CONDITION_STATUS_INVALID * if invalid paramenters are passed. */ extern enum lttng_condition_status lttng_condition_buffer_usage_set_domain_type( struct lttng_condition *condition, enum lttng_domain_type type); /** * lttng_evaluation_buffer_usage are specialised lttng_evaluations which * allow users to query a number of properties resulting from the evaluation * of a condition which evaluated to true. * * The evaluation of a buffer usage condition yields two different results: * - the usage ratio of the channel buffers at the time of the evaluation, * - the usage, in bytes, of the channel buffers at the time of evaluation. */ /* * Get the buffer usage ratio property of a buffer usage evaluation. * * Returns LTTNG_EVALUATION_STATUS_OK on success and a threshold expressed as * as a ratio of the buffer's capacity, or LTTNG_EVALUATION_STATUS_INVALID if * an invalid parameter is passed. */ extern enum lttng_evaluation_status lttng_evaluation_buffer_usage_get_usage_ratio( const struct lttng_evaluation *evaluation, double *usage_ratio); /* * Get the buffer usage property of a buffer usage evaluation. * * Returns LTTNG_EVALUATION_STATUS_OK on success and a threshold expressed in * bytes, or LTTNG_EVALUATION_STATUS_INVALID if an invalid parameter is passed. */ extern enum lttng_evaluation_status lttng_evaluation_buffer_usage_get_usage( const struct lttng_evaluation *evaluation, uint64_t *usage_bytes); #ifdef __cplusplus } #endif #endif /* LTTNG_CONDITION_BUFFER_USAGE_H */