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fc6323ad82
It remains cumbersome to preserve two versions of the freq counters and two different internal clocks just for this. In addition, the savings from using two different mechanisms are not that important as the only saving is a divide that is replaced by a multiply, but now thanks to the freq_ctr_total() unificaiton the code could also be simplified to optimize it in case of constants. This patch turns all non-period freq_ctr functions to static inlines which call the period-based ones with a period of 1 second. A direct benefit is that a single internal clock is now needed for any counter and that they now all rely on ticks. These 1-second counters are essentially used to report request rates and to enforce a connection rate limitation in listeners. It was verified that these continue to work like before.
86 lines
2.2 KiB
C
86 lines
2.2 KiB
C
/*
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* Event rate calculation functions.
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*
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* Copyright 2000-2010 Willy Tarreau <w@1wt.eu>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*
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*/
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#include <haproxy/api.h>
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#include <haproxy/freq_ctr.h>
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#include <haproxy/time.h>
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#include <haproxy/tools.h>
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/* Returns the total number of events over the current + last period, including
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* a number of already pending events <pend>. The average frequency will be
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* obtained by dividing the output by <period>. This is essentially made to
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* ease implementation of higher-level read functions.
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*
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* As a special case, if pend < 0, it's assumed there are no pending
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* events and a flapping correction must be applied at the end. This is used by
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* read_freq_ctr_period() to avoid reporting ups and downs on low-frequency
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* events when the past value is <= 1.
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*/
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ullong freq_ctr_total(struct freq_ctr *ctr, uint period, int pend)
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{
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ullong curr, past;
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uint curr_tick;
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int remain;
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for (;; __ha_cpu_relax()) {
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curr = ctr->curr_ctr;
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past = ctr->prev_ctr;
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curr_tick = ctr->curr_tick;
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/* now let's make sure the second loads retrieve the most
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* up-to-date values. If no value changed after a load barrier,
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* we're certain the values we got were stable.
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*/
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__ha_barrier_load();
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if (curr_tick & 0x1)
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continue;
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if (curr != ctr->curr_ctr)
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continue;
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if (past != ctr->prev_ctr)
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continue;
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if (curr_tick != ctr->curr_tick)
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continue;
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break;
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};
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remain = curr_tick + period - global_now_ms;
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if (unlikely(remain < 0)) {
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/* We're past the first period, check if we can still report a
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* part of last period or if we're too far away.
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*/
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remain += period;
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past = (remain >= 0) ? curr : 0;
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curr = 0;
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}
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if (pend < 0) {
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/* enable flapping correction at very low rates */
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pend = 0;
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if (!curr && past <= 1)
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return past * period;
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}
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/* compute the total number of confirmed events over the period */
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return past * remain + (curr + pend) * period;
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}
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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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