| 1 | /* |
| 2 | * Copyright (C) 2017 Jérémie Galarneau <jeremie.galarneau@efficios.com> |
| 3 | * |
| 4 | * SPDX-License-Identifier: LGPL-2.1-only |
| 5 | * |
| 6 | */ |
| 7 | |
| 8 | #ifndef LTTNG_CONDITION_BUFFER_USAGE_H |
| 9 | #define LTTNG_CONDITION_BUFFER_USAGE_H |
| 10 | |
| 11 | #include <lttng/condition/evaluation.h> |
| 12 | #include <lttng/condition/condition.h> |
| 13 | #include <stdint.h> |
| 14 | #include <lttng/domain.h> |
| 15 | #include <lttng/lttng-export.h> |
| 16 | |
| 17 | #ifdef __cplusplus |
| 18 | extern "C" { |
| 19 | #endif |
| 20 | |
| 21 | /** |
| 22 | * Buffer usage conditions allows an action to be taken whenever a channel's |
| 23 | * buffer usage crosses a set threshold. |
| 24 | * |
| 25 | * These conditions are periodically evaluated against the current buffer |
| 26 | * usage statistics. The period at which these conditions are evaluated is |
| 27 | * governed by the channels' monitor timer. |
| 28 | * |
| 29 | * Note that the use of these conditons does not imply any hysteresis-loop |
| 30 | * mechanism. For instance, an upper-bound buffer usage condition set to 75% |
| 31 | * will fire everytime the buffer usage goes from a value < 75% to a value that |
| 32 | * is >= 75%. The evaluation result does not depend on any lower-bound condition |
| 33 | * being reached before the condition is evaluated to true again. |
| 34 | * |
| 35 | * Buffer usage conditions have the following properties: |
| 36 | * - the exact name of the session in which the channel to be monitored is |
| 37 | * defined, |
| 38 | * - the domain of the channel to be monitored, |
| 39 | * - the exact name of the channel to be monitored, |
| 40 | * - a usage threshold, expressed either in bytes or as a fraction of total |
| 41 | * buffer capacity. |
| 42 | * |
| 43 | * Wildcards, regular expressions or other globbing mechanisms are not supported |
| 44 | * in buffer usage condition properties. |
| 45 | */ |
| 46 | |
| 47 | /* |
| 48 | * Create a newly allocated lower-bound buffer usage condition. |
| 49 | * |
| 50 | * A lower-bound buffer usage condition evaluates to true whenever |
| 51 | * a buffer's usage _crosses_ the bound that is defined as part of the |
| 52 | * condition's properties from high to low. In other words, the condition only |
| 53 | * evaluates to true when a buffer's usage transitions from a value higher than |
| 54 | * the threshold defined in the condition to a value lower than the threshold |
| 55 | * defined in the condition. |
| 56 | * |
| 57 | * Returns a new condition on success, NULL on failure. This condition must be |
| 58 | * destroyed using lttng_condition_destroy(). |
| 59 | */ |
| 60 | LTTNG_EXPORT extern struct lttng_condition * |
| 61 | lttng_condition_buffer_usage_low_create(void); |
| 62 | |
| 63 | /* |
| 64 | * Create a newly allocated upper-bound buffer usage condition. |
| 65 | * |
| 66 | * An upper-bound buffer usage condition evaluates to true whenever |
| 67 | * a buffer's usage _crosses_ the bound that is defined as part of the |
| 68 | * condition's properties from low to high. In other words, the condition only |
| 69 | * evaluates to true when a buffer's usage transitions from a value lower than |
| 70 | * the threshold defined in the condition to a value higher than the threshold |
| 71 | * defined in the condition. |
| 72 | * |
| 73 | * Returns a new condition on success, NULL on failure. This condition must be |
| 74 | * destroyed using lttng_condition_destroy(). |
| 75 | */ |
| 76 | LTTNG_EXPORT extern struct lttng_condition * |
| 77 | lttng_condition_buffer_usage_high_create(void); |
| 78 | |
| 79 | /* |
| 80 | * Get the buffer usage threshold ratio of a buffer usage condition. |
| 81 | * |
| 82 | * The buffer usage condition's threshold must have been defined as a ratio in |
| 83 | * order for this call to succeed. |
| 84 | * |
| 85 | * Returns LTTNG_CONDITION_STATUS_OK on success and a ratio contained by the |
| 86 | * interval [0.0, 1.0]. LTTNG_CONDITION_STATUS_INVALID is returned if an invalid |
| 87 | * parameter is passed, or LTTNG_CONDITION_STATUS_UNSET if a threshold, |
| 88 | * expressed as a ratio of total buffer capacity, was not set prior to this |
| 89 | * call. |
| 90 | */ |
| 91 | LTTNG_EXPORT extern enum lttng_condition_status |
| 92 | lttng_condition_buffer_usage_get_threshold_ratio( |
| 93 | const struct lttng_condition *condition, |
| 94 | double *threshold_ratio); |
| 95 | |
| 96 | /* |
| 97 | * Set the buffer usage threshold ratio of a buffer usage condition. |
| 98 | * |
| 99 | * The threshold ratio passed must be contained by the interval [0.0, 1.0] and |
| 100 | * represents a ratio of the channel's buffer's capacity. Setting a threshold, |
| 101 | * either as a ratio or as an absolute size in bytes will override any |
| 102 | * previously set threshold. |
| 103 | * |
| 104 | * Returns LTTNG_CONDITION_STATUS_OK on success, LTTNG_CONDITION_STATUS_INVALID |
| 105 | * if invalid paramenters are passed. |
| 106 | */ |
| 107 | LTTNG_EXPORT extern enum lttng_condition_status |
| 108 | lttng_condition_buffer_usage_set_threshold_ratio( |
| 109 | struct lttng_condition *condition, |
| 110 | double threshold_ratio); |
| 111 | |
| 112 | /* |
| 113 | * Get the buffer usage threshold of a buffer usage condition. |
| 114 | * |
| 115 | * The buffer usage condition's threshold must have been defined as an absolute |
| 116 | * value expressed in bytes in order for this call to succeed. |
| 117 | * |
| 118 | * Returns LTTNG_CONDITION_STATUS_OK on success and a threshold expressed in |
| 119 | * bytes, LTTNG_CONDITION_STATUS_INVALID if an invalid parameter is passed, or |
| 120 | * LTTNG_CONDITION_STATUS_UNSET if a threshold, expressed as an absolute size in |
| 121 | * bytes, was not set prior to this call. |
| 122 | */ |
| 123 | LTTNG_EXPORT extern enum lttng_condition_status |
| 124 | lttng_condition_buffer_usage_get_threshold( |
| 125 | const struct lttng_condition *condition, |
| 126 | uint64_t *threshold_bytes); |
| 127 | |
| 128 | /* |
| 129 | * Set the buffer usage threshold in bytes of a buffer usage condition. |
| 130 | * |
| 131 | * Setting a threshold, either as a ratio or as an absolute size in bytes |
| 132 | * will override any previously set threshold. |
| 133 | * |
| 134 | * Returns LTTNG_CONDITION_STATUS_OK on success, LTTNG_CONDITION_STATUS_INVALID |
| 135 | * if invalid paramenters are passed. |
| 136 | */ |
| 137 | LTTNG_EXPORT extern enum lttng_condition_status |
| 138 | lttng_condition_buffer_usage_set_threshold( |
| 139 | struct lttng_condition *condition, |
| 140 | uint64_t threshold_bytes); |
| 141 | |
| 142 | /* |
| 143 | * Get the session name property of a buffer usage condition. |
| 144 | * |
| 145 | * The caller does not assume the ownership of the returned session name. The |
| 146 | * session name shall only only be used for the duration of the condition's |
| 147 | * lifetime, or before a different session name is set. |
| 148 | * |
| 149 | * Returns LTTNG_CONDITION_STATUS_OK and a pointer to the condition's session |
| 150 | * name on success, LTTNG_CONDITION_STATUS_INVALID if an invalid |
| 151 | * parameter is passed, or LTTNG_CONDITION_STATUS_UNSET if a session name |
| 152 | * was not set prior to this call. |
| 153 | */ |
| 154 | LTTNG_EXPORT extern enum lttng_condition_status |
| 155 | lttng_condition_buffer_usage_get_session_name( |
| 156 | const struct lttng_condition *condition, |
| 157 | const char **session_name); |
| 158 | |
| 159 | /* |
| 160 | * Set the session name property of a buffer usage condition. |
| 161 | * |
| 162 | * The passed session name parameter will be copied to the condition. |
| 163 | * |
| 164 | * Returns LTTNG_CONDITION_STATUS_OK on success, LTTNG_CONDITION_STATUS_INVALID |
| 165 | * if invalid paramenters are passed. |
| 166 | */ |
| 167 | LTTNG_EXPORT extern enum lttng_condition_status |
| 168 | lttng_condition_buffer_usage_set_session_name( |
| 169 | struct lttng_condition *condition, |
| 170 | const char *session_name); |
| 171 | |
| 172 | /* |
| 173 | * Get the channel name property of a buffer usage condition. |
| 174 | * |
| 175 | * The caller does not assume the ownership of the returned channel name. The |
| 176 | * channel name shall only only be used for the duration of the condition's |
| 177 | * lifetime, or before a different channel name is set. |
| 178 | * |
| 179 | * Returns LTTNG_CONDITION_STATUS_OK and a pointer to the condition's channel |
| 180 | * name on success, LTTNG_CONDITION_STATUS_INVALID if an invalid |
| 181 | * parameter is passed, or LTTNG_CONDITION_STATUS_UNSET if a channel name |
| 182 | * was not set prior to this call. |
| 183 | */ |
| 184 | LTTNG_EXPORT extern enum lttng_condition_status |
| 185 | lttng_condition_buffer_usage_get_channel_name( |
| 186 | const struct lttng_condition *condition, |
| 187 | const char **channel_name); |
| 188 | |
| 189 | /* |
| 190 | * Set the channel name property of a buffer usage condition. |
| 191 | * |
| 192 | * The passed channel name parameter will be copied to the condition. |
| 193 | * |
| 194 | * Returns LTTNG_CONDITION_STATUS_OK on success, LTTNG_CONDITION_STATUS_INVALID |
| 195 | * if invalid paramenters are passed. |
| 196 | */ |
| 197 | LTTNG_EXPORT extern enum lttng_condition_status |
| 198 | lttng_condition_buffer_usage_set_channel_name( |
| 199 | struct lttng_condition *condition, |
| 200 | const char *channel_name); |
| 201 | |
| 202 | /* |
| 203 | * Get the domain type property of a buffer usage condition. |
| 204 | * |
| 205 | * Returns LTTNG_CONDITION_STATUS_OK and sets the domain type output parameter |
| 206 | * on success, LTTNG_CONDITION_STATUS_INVALID if an invalid parameter is passed, |
| 207 | * or LTTNG_CONDITION_STATUS_UNSET if a domain type was not set prior to this |
| 208 | * call. |
| 209 | */ |
| 210 | LTTNG_EXPORT extern enum lttng_condition_status |
| 211 | lttng_condition_buffer_usage_get_domain_type( |
| 212 | const struct lttng_condition *condition, |
| 213 | enum lttng_domain_type *type); |
| 214 | |
| 215 | /* |
| 216 | * Set the domain type property of a buffer usage condition. |
| 217 | * |
| 218 | * Returns LTTNG_CONDITION_STATUS_OK on success, LTTNG_CONDITION_STATUS_INVALID |
| 219 | * if invalid paramenters are passed. |
| 220 | */ |
| 221 | LTTNG_EXPORT extern enum lttng_condition_status |
| 222 | lttng_condition_buffer_usage_set_domain_type( |
| 223 | struct lttng_condition *condition, |
| 224 | enum lttng_domain_type type); |
| 225 | |
| 226 | |
| 227 | /** |
| 228 | * lttng_evaluation_buffer_usage are specialised lttng_evaluations which |
| 229 | * allow users to query a number of properties resulting from the evaluation |
| 230 | * of a condition which evaluated to true. |
| 231 | * |
| 232 | * The evaluation of a buffer usage condition yields two different results: |
| 233 | * - the usage ratio of the channel buffers at the time of the evaluation, |
| 234 | * - the usage, in bytes, of the channel buffers at the time of evaluation. |
| 235 | */ |
| 236 | |
| 237 | /* |
| 238 | * Get the buffer usage ratio property of a buffer usage evaluation. |
| 239 | * |
| 240 | * Returns LTTNG_EVALUATION_STATUS_OK on success and a threshold expressed as |
| 241 | * as a ratio of the buffer's capacity, or LTTNG_EVALUATION_STATUS_INVALID if |
| 242 | * an invalid parameter is passed. |
| 243 | */ |
| 244 | LTTNG_EXPORT extern enum lttng_evaluation_status |
| 245 | lttng_evaluation_buffer_usage_get_usage_ratio( |
| 246 | const struct lttng_evaluation *evaluation, |
| 247 | double *usage_ratio); |
| 248 | |
| 249 | /* |
| 250 | * Get the buffer usage property of a buffer usage evaluation. |
| 251 | * |
| 252 | * Returns LTTNG_EVALUATION_STATUS_OK on success and a threshold expressed in |
| 253 | * bytes, or LTTNG_EVALUATION_STATUS_INVALID if an invalid parameter is passed. |
| 254 | */ |
| 255 | LTTNG_EXPORT extern enum lttng_evaluation_status |
| 256 | lttng_evaluation_buffer_usage_get_usage( |
| 257 | const struct lttng_evaluation *evaluation, |
| 258 | uint64_t *usage_bytes); |
| 259 | |
| 260 | #ifdef __cplusplus |
| 261 | } |
| 262 | #endif |
| 263 | |
| 264 | #endif /* LTTNG_CONDITION_BUFFER_USAGE_H */ |