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https://git.kernel.org/pub/scm/network/iproute2/iproute2.git
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f0bda7e5a5
[IPROUTE]: Introduce TIME_UNITS_PER_SEC to represent internal clock resolution Introduce TIME_UNITS_PER_SEC and conversion functions between internal resolution and resolution expected by the kernel (currently implemented as NOPs, only needed by HFSC, which currently always uses microseconds). Signed-off-by: Patrick McHardy <kaber@trash.net> Signed-off-by: Stephen Hemminger <shemminger@linux-foundation.org>
45 lines
1.1 KiB
C
45 lines
1.1 KiB
C
/*
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* tc_core.c TC core library.
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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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* Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
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*
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <syslog.h>
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#include <fcntl.h>
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#include <math.h>
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#include <sys/socket.h>
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#include <netinet/in.h>
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#include <arpa/inet.h>
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#include <string.h>
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#include "tc_core.h"
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int tc_setup_estimator(unsigned A, unsigned time_const, struct tc_estimator *est)
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{
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for (est->interval=0; est->interval<=5; est->interval++) {
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if (A <= (1<<est->interval)*(TIME_UNITS_PER_SEC/4))
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break;
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}
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if (est->interval > 5)
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return -1;
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est->interval -= 2;
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for (est->ewma_log=1; est->ewma_log<32; est->ewma_log++) {
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double w = 1.0 - 1.0/(1<<est->ewma_log);
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if (A/(-log(w)) > time_const)
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break;
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}
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est->ewma_log--;
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if (est->ewma_log==0 || est->ewma_log >= 31)
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return -1;
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return 0;
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}
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