/* * librdkafka - Apache Kafka C library * * Copyright (c) 2018-2022, Magnus Edenhill * 2023 Confluent Inc. * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions are met: * * 1. Redistributions of source code must retain the above copyright notice, * this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright notice, * this list of conditions and the following disclaimer in the documentation * and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE * POSSIBILITY OF SUCH DAMAGE. */ #ifndef _RDINTERVAL_H_ #define _RDINTERVAL_H_ #include "rd.h" #include "rdrand.h" typedef struct rd_interval_s { rd_ts_t ri_ts_last; /* last interval timestamp */ rd_ts_t ri_fixed; /* fixed interval if provided interval is 0 */ int ri_backoff; /* back off the next interval by this much */ } rd_interval_t; static RD_INLINE RD_UNUSED void rd_interval_init(rd_interval_t *ri) { memset(ri, 0, sizeof(*ri)); } /** * Returns the number of microseconds the interval has been over-shot. * If the return value is >0 (i.e., time for next intervalled something) then * the time interval is updated to the current time. * * The current time can be provided in 'now', or if this is set to 0 the time * will be gathered automatically. * * If 'interval_us' is set to 0 the fixed interval will be used, see * 'rd_interval_fixed()'. * * If this is the first time rd_interval() is called after an _init() or * _reset() or the \p immediate parameter is true, then a positive value * will be returned immediately even though the initial interval has not * passed. */ #define rd_interval(ri, interval_us, now) rd_interval0(ri, interval_us, now, 0) #define rd_interval_immediate(ri, interval_us, now) \ rd_interval0(ri, interval_us, now, 1) static RD_INLINE RD_UNUSED rd_ts_t rd_interval0(rd_interval_t *ri, rd_ts_t interval_us, rd_ts_t now, int immediate) { rd_ts_t diff; if (!now) now = rd_clock(); if (!interval_us) interval_us = ri->ri_fixed; if (ri->ri_ts_last || !immediate) { diff = now - (ri->ri_ts_last + interval_us + ri->ri_backoff); } else diff = 1; if (unlikely(diff > 0)) { ri->ri_ts_last = now; ri->ri_backoff = 0; } return diff; } /** * Reset the interval to zero, i.e., the next call to rd_interval() * will be immediate. */ static RD_INLINE RD_UNUSED void rd_interval_reset(rd_interval_t *ri) { ri->ri_ts_last = 0; ri->ri_backoff = 0; } /** * Reset the interval to 'now'. If now is 0, the time will be gathered * automatically. */ static RD_INLINE RD_UNUSED void rd_interval_reset_to_now(rd_interval_t *ri, rd_ts_t now) { if (!now) now = rd_clock(); ri->ri_ts_last = now; ri->ri_backoff = 0; } /** * Reset the interval to 'now' with the given backoff ms and max_jitter as * percentage. The backoff is given just for absolute jitter calculation. If now * is 0, the time will be gathered automatically. */ static RD_INLINE RD_UNUSED void rd_interval_reset_to_now_with_jitter(rd_interval_t *ri, rd_ts_t now, int64_t backoff_ms, int max_jitter) { rd_interval_reset_to_now(ri, now); /* We are multiplying by 10 as (backoff_ms * percent * 1000)/100 -> * backoff_ms * jitter * 10 */ ri->ri_backoff = backoff_ms * rd_jitter(-max_jitter, max_jitter) * 10; } /** * Back off the next interval by `backoff_us` microseconds. */ static RD_INLINE RD_UNUSED void rd_interval_backoff(rd_interval_t *ri, int backoff_us) { ri->ri_backoff = backoff_us; } /** * Expedite (speed up) the next interval by `expedite_us` microseconds. * If `expedite_us` is 0 the interval will be set to trigger * immedately on the next rd_interval() call. */ static RD_INLINE RD_UNUSED void rd_interval_expedite(rd_interval_t *ri, int expedite_us) { if (!expedite_us) ri->ri_ts_last = 0; else ri->ri_backoff = -expedite_us; } /** * Specifies a fixed interval to use if rd_interval() is called with * `interval_us` set to 0. */ static RD_INLINE RD_UNUSED void rd_interval_fixed(rd_interval_t *ri, rd_ts_t fixed_us) { ri->ri_fixed = fixed_us; } /** * Disables the interval (until rd_interval_init()/reset() is called). * A disabled interval will never return a positive value from * rd_interval(). */ static RD_INLINE RD_UNUSED void rd_interval_disable(rd_interval_t *ri) { /* Set last beat to a large value a long time in the future. */ ri->ri_ts_last = 6000000000000000000LL; /* in about 190000 years */ } /** * Returns true if the interval is disabled. */ static RD_INLINE RD_UNUSED int rd_interval_disabled(const rd_interval_t *ri) { return ri->ri_ts_last == 6000000000000000000LL; } #endif /* _RDINTERVAL_H_ */