blob: 0abcc9da2d49e319de2611877765e6c75f657f2e [file] [log] [blame]
/*
* tc_cbq.c CBQ maintanance routines.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*
* Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
*
*/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <syslog.h>
#include <fcntl.h>
#include <math.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <string.h>
#include "tc_core.h"
#include "tc_cbq.h"
unsigned tc_cbq_calc_maxidle(unsigned bndw, unsigned rate, unsigned avpkt,
int ewma_log, unsigned maxburst)
{
double maxidle;
double g = 1.0 - 1.0/(1<<ewma_log);
double xmt = (double)avpkt/bndw;
maxidle = xmt*(1-g);
if (bndw != rate && maxburst) {
double vxmt = (double)avpkt/rate - xmt;
vxmt *= (pow(g, -(double)maxburst) - 1);
if (vxmt > maxidle)
maxidle = vxmt;
}
return tc_core_usec2tick(maxidle*(1<<ewma_log)*1000000);
}
unsigned tc_cbq_calc_offtime(unsigned bndw, unsigned rate, unsigned avpkt,
int ewma_log, unsigned minburst)
{
double g = 1.0 - 1.0/(1<<ewma_log);
double offtime = (double)avpkt/rate - (double)avpkt/bndw;
if (minburst == 0)
return 0;
if (minburst == 1)
offtime *= pow(g, -(double)minburst) - 1;
else
offtime *= 1 + (pow(g, -(double)(minburst-1)) - 1)/(1-g);
return tc_core_usec2tick(offtime*1000000);
}