Function tf_cwnd

freebsd/netinet/cc/cc_cubic.h:237–247

* Compute an approximation of the "TCP friendly" cwnd some number of ticks * after a congestion event that is designed to yield the same average cwnd as * NewReno while using CUBIC's beta of 0.7. RTT should be the average RTT * estimate for the path measured over the previous congestion epoch and wmax is * the value of cwnd at the last congestion event. */

 * the value of cwnd at the last congestion event.
 */
static __inline unsigned long
tf_cwnd(int ticks_since_cong, int rtt_ticks, unsigned long wmax,
    uint32_t smss)
{

	/* Equation 4 of I-D. */
	return (((wmax * CUBIC_BETA) +
	    (((THREE_X_PT3 * (unsigned long)ticks_since_cong *
	    (unsigned long)smss) << CUBIC_SHIFT) / (TWO_SUB_PT3 * rtt_ticks)))
	    >> CUBIC_SHIFT);
}

#endif /* _NETINET_CC_CUBIC_H_ */