13  *    "while (ca->ack_cnt > delta)" loop is changed to the equivalent
14  *    "ca->ack_cnt / delta" operation.
102 static void bictcp_reset(struct bpf_bictcp *ca)  in bictcp_reset()  argument
104 	ca->cnt = 0;  in bictcp_reset()
105 	ca->last_max_cwnd = 0;  in bictcp_reset()
106 	ca->last_cwnd = 0;  in bictcp_reset()
107 	ca->last_time = 0;  in bictcp_reset()
108 	ca->bic_origin_point = 0;  in bictcp_reset()
109 	ca->bic_K = 0;  in bictcp_reset()
110 	ca->delay_min = 0;  in bictcp_reset()
111 	ca->epoch_start = 0;  in bictcp_reset()
112 	ca->ack_cnt = 0;  in bictcp_reset()
113 	ca->tcp_cwnd = 0;  in bictcp_reset()
114 	ca->found = 0;  in bictcp_reset()
172 	struct bpf_bictcp *ca = inet_csk_ca(sk);  in bictcp_hystart_reset()  local
174 	ca->round_start = ca->last_ack = bictcp_clock_us(sk);  in bictcp_hystart_reset()
175 	ca->end_seq = tp->snd_nxt;  in bictcp_hystart_reset()
176 	ca->curr_rtt = ~0U;  in bictcp_hystart_reset()
177 	ca->sample_cnt = 0;  in bictcp_hystart_reset()
183 	struct bpf_bictcp *ca = inet_csk_ca(sk);  in BPF_PROG()  local
185 	bictcp_reset(ca);  in BPF_PROG()
198 		struct bpf_bictcp *ca = inet_csk_ca(sk);  in BPF_PROG()  local
207 		if (ca->epoch_start && delta > 0) {  in BPF_PROG()
208 			ca->epoch_start += delta;  in BPF_PROG()
209 			if (after(ca->epoch_start, now))  in BPF_PROG()
210 				ca->epoch_start = now;  in BPF_PROG()
272 static void bictcp_update(struct bpf_bictcp *ca, __u32 cwnd, __u32 acked)  in bictcp_update()  argument
277 	ca->ack_cnt += acked;	/* count the number of ACKed packets */  in bictcp_update()
279 	if (ca->last_cwnd == cwnd &&  in bictcp_update()
280 	    (__s32)(tcp_jiffies32 - ca->last_time) <= HZ / 32)  in bictcp_update()
283 	/* The CUBIC function can update ca->cnt at most once per jiffy.  in bictcp_update()
284 	 * On all cwnd reduction events, ca->epoch_start is set to 0,  in bictcp_update()
285 	 * which will force a recalculation of ca->cnt.  in bictcp_update()
287 	if (ca->epoch_start && tcp_jiffies32 == ca->last_time)  in bictcp_update()
290 	ca->last_cwnd = cwnd;  in bictcp_update()
291 	ca->last_time = tcp_jiffies32;  in bictcp_update()
293 	if (ca->epoch_start == 0) {  in bictcp_update()
294 		ca->epoch_start = tcp_jiffies32;	/* record beginning */  in bictcp_update()
295 		ca->ack_cnt = acked;			/* start counting */  in bictcp_update()
296 		ca->tcp_cwnd = cwnd;			/* syn with cubic */  in bictcp_update()
298 		if (ca->last_max_cwnd <= cwnd) {  in bictcp_update()
299 			ca->bic_K = 0;  in bictcp_update()
300 			ca->bic_origin_point = cwnd;  in bictcp_update()
305 			ca->bic_K = cubic_root(cube_factor  in bictcp_update()
306 					       * (ca->last_max_cwnd - cwnd));  in bictcp_update()
307 			ca->bic_origin_point = ca->last_max_cwnd;  in bictcp_update()
325 	t = (__s32)(tcp_jiffies32 - ca->epoch_start) * USEC_PER_JIFFY;  in bictcp_update()
326 	t += ca->delay_min;  in bictcp_update()
331 	if (t < ca->bic_K)		/* t - K */  in bictcp_update()
332 		offs = ca->bic_K - t;  in bictcp_update()
334 		offs = t - ca->bic_K;  in bictcp_update()
338 	if (t < ca->bic_K)                            /* below origin*/  in bictcp_update()
339 		bic_target = ca->bic_origin_point - delta;  in bictcp_update()
341 		bic_target = ca->bic_origin_point + delta;  in bictcp_update()
345 		ca->cnt = cwnd / (bic_target - cwnd);  in bictcp_update()
347 		ca->cnt = 100 * cwnd;              /* very small increment*/  in bictcp_update()
354 	if (ca->last_max_cwnd == 0 && ca->cnt > 20)  in bictcp_update()
355 		ca->cnt = 20;	/* increase cwnd 5% per RTT */  in bictcp_update()
365 		if (ca->ack_cnt > delta && delta) {  in bictcp_update()
366 			n = ca->ack_cnt / delta;  in bictcp_update()
367 			ca->ack_cnt -= n * delta;  in bictcp_update()
368 			ca->tcp_cwnd += n;  in bictcp_update()
371 		if (ca->tcp_cwnd > cwnd) {	/* if bic is slower than tcp */  in bictcp_update()
372 			delta = ca->tcp_cwnd - cwnd;  in bictcp_update()
374 			if (ca->cnt > max_cnt)  in bictcp_update()
375 				ca->cnt = max_cnt;  in bictcp_update()
382 	ca->cnt = max(ca->cnt, 2U);  in bictcp_update()
389 	struct bpf_bictcp *ca = inet_csk_ca(sk);  in BPF_PROG()  local
395 		if (hystart && after(ack, ca->end_seq))  in BPF_PROG()
401 	bictcp_update(ca, tp->snd_cwnd, acked);  in BPF_PROG()
402 	tcp_cong_avoid_ai(tp, ca->cnt, acked);  in BPF_PROG()
409 	struct bpf_bictcp *ca = inet_csk_ca(sk);  in BPF_PROG()  local
411 	ca->epoch_start = 0;	/* end of epoch */  in BPF_PROG()
414 	if (tp->snd_cwnd < ca->last_max_cwnd && fast_convergence)  in BPF_PROG()
415 		ca->last_max_cwnd = (tp->snd_cwnd * (BICTCP_BETA_SCALE + beta))  in BPF_PROG()
418 		ca->last_max_cwnd = tp->snd_cwnd;  in BPF_PROG()
436  * slow start we begin with small TSO packets and ca->delay_min would
457 	struct bpf_bictcp *ca = inet_csk_ca(sk);  in hystart_update()  local
464 		if ((__s32)(now - ca->last_ack) <= hystart_ack_delta_us) {  in hystart_update()
465 			ca->last_ack = now;  in hystart_update()
467 			threshold = ca->delay_min + hystart_ack_delay(sk);  in hystart_update()
470 			 * ca->delay_min/2.  in hystart_update()
477 			if ((__s32)(now - ca->round_start) > threshold) {  in hystart_update()
478 				ca->found = 1;  in hystart_update()
486 		if (ca->curr_rtt > delay)  in hystart_update()
487 			ca->curr_rtt = delay;  in hystart_update()
488 		if (ca->sample_cnt < HYSTART_MIN_SAMPLES) {  in hystart_update()
489 			ca->sample_cnt++;  in hystart_update()
491 			if (ca->curr_rtt > ca->delay_min +  in hystart_update()
492 			    HYSTART_DELAY_THRESH(ca->delay_min >> 3)) {  in hystart_update()
493 				ca->found = 1;  in hystart_update()
506 	struct bpf_bictcp *ca = inet_csk_ca(sk);  in BPF_PROG()  local
515 	if (ca->epoch_start && (__s32)(tcp_jiffies32 - ca->epoch_start) < HZ)  in BPF_PROG()
523 	if (ca->delay_min == 0 || ca->delay_min > delay)  in BPF_PROG()
524 		ca->delay_min = delay;  in BPF_PROG()
527 	if (!ca->found && tcp_in_slow_start(tp) && hystart &&  in BPF_PROG()