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Some freq counters will have to work on periods different from 1 second. The original freq counters rely on the period to be exactly one second. The new ones (freq_ctr_period) let the user define the period in ticks, and all computations are operated over that period. When reading a value, it indicates the amount of events over that period too.
126 lines
4.3 KiB
C
126 lines
4.3 KiB
C
/*
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include/proto/freq_ctr.h
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This file contains macros and inline functions for frequency counters.
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Copyright (C) 2000-2009 Willy Tarreau - w@1wt.eu
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This library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation, version 2.1
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exclusively.
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This library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with this library; if not, write to the Free Software
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Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#ifndef _PROTO_FREQ_CTR_H
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#define _PROTO_FREQ_CTR_H
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#include <common/config.h>
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#include <common/time.h>
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#include <types/freq_ctr.h>
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/* Rotate a frequency counter when current period is over. Must not be called
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* during a valid period. It is important that it correctly initializes a null
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* area.
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*/
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static inline void rotate_freq_ctr(struct freq_ctr *ctr)
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{
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ctr->prev_ctr = ctr->curr_ctr;
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if (likely(now.tv_sec - ctr->curr_sec != 1)) {
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/* we missed more than one second */
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ctr->prev_ctr = 0;
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}
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ctr->curr_sec = now.tv_sec;
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ctr->curr_ctr = 0; /* leave it at the end to help gcc optimize it away */
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}
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/* Update a frequency counter by <inc> incremental units. It is automatically
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* rotated if the period is over. It is important that it correctly initializes
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* a null area.
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*/
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static inline void update_freq_ctr(struct freq_ctr *ctr, unsigned int inc)
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{
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if (likely(ctr->curr_sec == now.tv_sec)) {
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ctr->curr_ctr += inc;
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return;
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}
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rotate_freq_ctr(ctr);
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ctr->curr_ctr = inc;
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/* Note: later we may want to propagate the update to other counters */
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}
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/* Rotate a frequency counter when current period is over. Must not be called
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* during a valid period. It is important that it correctly initializes a null
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* area. This one works on frequency counters which have a period different
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* from one second.
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*/
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static inline void rotate_freq_ctr_period(struct freq_ctr_period *ctr,
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unsigned int period)
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{
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ctr->prev_ctr = ctr->curr_ctr;
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ctr->curr_tick += period;
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if (likely(now_ms - ctr->curr_tick >= period)) {
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/* we missed at least two periods */
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ctr->prev_ctr = 0;
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ctr->curr_tick = now_ms;
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}
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ctr->curr_ctr = 0; /* leave it at the end to help gcc optimize it away */
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}
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/* Update a frequency counter by <inc> incremental units. It is automatically
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* rotated if the period is over. It is important that it correctly initializes
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* a null area. This one works on frequency counters which have a period
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* different from one second.
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*/
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static inline void update_freq_ctr_period(struct freq_ctr_period *ctr,
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unsigned int period, unsigned int inc)
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{
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if (likely(now_ms - ctr->curr_tick < period)) {
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ctr->curr_ctr += inc;
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return;
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}
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rotate_freq_ctr_period(ctr, period);
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ctr->curr_ctr = inc;
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/* Note: later we may want to propagate the update to other counters */
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}
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/* Read a frequency counter taking history into account for missing time in
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* current period.
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*/
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unsigned int read_freq_ctr(struct freq_ctr *ctr);
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/* returns the number of remaining events that can occur on this freq counter
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* while respecting <freq> and taking into account that <pend> events are
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* already known to be pending. Returns 0 if limit was reached.
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*/
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unsigned int freq_ctr_remain(struct freq_ctr *ctr, unsigned int freq, unsigned int pend);
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/* return the expected wait time in ms before the next event may occur,
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* respecting frequency <freq>, and assuming there may already be some pending
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* events. It returns zero if we can proceed immediately, otherwise the wait
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* time, which will be rounded down 1ms for better accuracy, with a minimum
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* of one ms.
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*/
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unsigned int next_event_delay(struct freq_ctr *ctr, unsigned int freq, unsigned int pend);
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/* process freq counters over configurable periods */
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unsigned int read_freq_ctr_period(struct freq_ctr_period *ctr, unsigned int period);
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unsigned int freq_ctr_remain_period(struct freq_ctr_period *ctr, unsigned int period,
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unsigned int freq, unsigned int pend);
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#endif /* _PROTO_FREQ_CTR_H */
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/*
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* Local variables:
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* c-indent-level: 8
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* c-basic-offset: 8
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* End:
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*/
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