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sys/netinet/cc/cc_cubic.h
| Show First 20 Lines • Show All 155 Lines • ▼ Show 20 Lines | cubic_k(unsigned long wmax_pkts) | ||||
| /* Multiply by 2^p to undo the rebasing of s from above. */ | /* Multiply by 2^p to undo the rebasing of s from above. */ | ||||
| return (K <<= p); | return (K <<= p); | ||||
| } | } | ||||
| /* | /* | ||||
| * Compute the new cwnd value using an implementation of eqn 1 from the I-D. | * Compute the new cwnd value using an implementation of eqn 1 from the I-D. | ||||
| * Thanks to Kip Macy for help debugging this function. | * Thanks to Kip Macy for help debugging this function. | ||||
| * | * | ||||
| * XXXLAS: Characterise bounds for overflow. | * XXXLAS: Characterise bounds for overflow. | ||||
jtl: It sounds like you may be doing the action item @lstewart left for himself. :-) | |||||
lstewartUnsubmitted Not Done Inline ActionsIndeed and mea culpa! :/ lstewart: Indeed and mea culpa! :/ | |||||
| */ | */ | ||||
| static __inline unsigned long | static __inline unsigned long | ||||
| cubic_cwnd(int ticks_since_cong, unsigned long wmax, uint32_t smss, int64_t K) | cubic_cwnd(int ticks_since_cong, unsigned long wmax, uint32_t smss, int64_t K) | ||||
| { | { | ||||
| int64_t cwnd; | int64_t cwnd; | ||||
| /* K is in fixed point form with CUBIC_SHIFT worth of precision. */ | /* K is in fixed point form with CUBIC_SHIFT worth of precision. */ | ||||
| /* t - K, with CUBIC_SHIFT worth of precision. */ | /* t - K, with CUBIC_SHIFT worth of precision. */ | ||||
| cwnd = ((int64_t)(ticks_since_cong << CUBIC_SHIFT) - (K * hz)) / hz; | cwnd = ((int64_t)(ticks_since_cong << CUBIC_SHIFT) - (K * hz)) / hz; | ||||
| /* (t - K)^3, with CUBIC_SHIFT^3 worth of precision. */ | /* (t - K)^3, with CUBIC_SHIFT^3 worth of precision. */ | ||||
| cwnd *= (cwnd * cwnd); | cwnd *= (cwnd * cwnd); | ||||
| /* | /* | ||||
| * C(t - K)^3 + wmax | * C(t - K)^3 + wmax | ||||
| * The down shift by CUBIC_SHIFT_4 is because cwnd has 4 lots of | * The down shift by CUBIC_SHIFT_4 is because cwnd has 4 lots of | ||||
| * CUBIC_SHIFT included in the value. 3 from the cubing of cwnd above, | * CUBIC_SHIFT included in the value. 3 from the cubing of cwnd above, | ||||
| * and an extra from multiplying through by CUBIC_C_FACTOR. | * and an extra from multiplying through by CUBIC_C_FACTOR. | ||||
| */ | */ | ||||
| cwnd = ((cwnd * CUBIC_C_FACTOR * smss) >> CUBIC_SHIFT_4) + wmax; | cwnd = ((cwnd * CUBIC_C_FACTOR * smss) >> CUBIC_SHIFT_4) + wmax; | ||||
| if (cwnd < (int64_t)smss) | |||||
| return (unsigned long)smss; | |||||
| return ((unsigned long)cwnd); | return ((unsigned long)cwnd); | ||||
| } | } | ||||
| /* | /* | ||||
| * Compute an approximation of the NewReno cwnd some number of ticks after a | * Compute an approximation of the NewReno cwnd some number of ticks after a | ||||
| * congestion event. RTT should be the average RTT estimate for the path | * congestion event. RTT should be the average RTT estimate for the path | ||||
| * measured over the previous congestion epoch and wmax is the value of cwnd at | * measured over the previous congestion epoch and wmax is the value of cwnd at | ||||
| * the last congestion event. The "TCP friendly" concept in the CUBIC I-D is | * the last congestion event. The "TCP friendly" concept in the CUBIC I-D is | ||||
| Show All 35 Lines | |||||
It sounds like you may be doing the action item @lstewart left for himself. :-)