1 /* 2 * tc_cbq.c CBQ maintanance routines. 3 * 4 * This program is free software; you can redistribute it and/or 5 * modify it under the terms of the GNU General Public License 6 * as published by the Free Software Foundation; either version 7 * 2 of the License, or (at your option) any later version. 8 * 9 * Authors: Alexey Kuznetsov, <kuznet (at) ms2.inr.ac.ru> 10 * 11 */ 12 13 #include <stdio.h> 14 #include <stdlib.h> 15 #include <unistd.h> 16 #include <syslog.h> 17 #include <fcntl.h> 18 #include <math.h> 19 #include <sys/socket.h> 20 #include <netinet/in.h> 21 #include <arpa/inet.h> 22 #include <string.h> 23 24 #include "tc_core.h" 25 #include "tc_cbq.h" 26 27 unsigned int tc_cbq_calc_maxidle(unsigned int bndw, unsigned int rate, unsigned int avpkt, 28 int ewma_log, unsigned int maxburst) 29 { 30 double maxidle; 31 double g = 1.0 - 1.0/(1<<ewma_log); 32 double xmt = (double)avpkt/bndw; 33 34 maxidle = xmt*(1-g); 35 if (bndw != rate && maxburst) { 36 double vxmt = (double)avpkt/rate - xmt; 37 38 vxmt *= (pow(g, -(double)maxburst) - 1); 39 if (vxmt > maxidle) 40 maxidle = vxmt; 41 } 42 return tc_core_time2tick(maxidle*(1<<ewma_log)*TIME_UNITS_PER_SEC); 43 } 44 45 unsigned int tc_cbq_calc_offtime(unsigned int bndw, unsigned int rate, unsigned int avpkt, 46 int ewma_log, unsigned int minburst) 47 { 48 double g = 1.0 - 1.0/(1<<ewma_log); 49 double offtime = (double)avpkt/rate - (double)avpkt/bndw; 50 51 if (minburst == 0) 52 return 0; 53 if (minburst == 1) 54 offtime *= pow(g, -(double)minburst) - 1; 55 else 56 offtime *= 1 + (pow(g, -(double)(minburst-1)) - 1)/(1-g); 57 return tc_core_time2tick(offtime*TIME_UNITS_PER_SEC); 58 } 59
