bpf/progs/bpf_cubic.c

13  *    "while (ca->ack_cnt > delta)" loop is changed to the equivalent
14  *    "ca->ack_cnt / delta" operation.
94 static inline void bictcp_reset(struct bictcp *ca)
96 	ca->cnt = 0;
97 	ca->last_max_cwnd = 0;
98 	ca->last_cwnd = 0;
99 	ca->last_time = 0;
100 	ca->bic_origin_point = 0;
101 	ca->bic_K = 0;
102 	ca->delay_min = 0;
103 	ca->epoch_start = 0;
104 	ca->ack_cnt = 0;
105 	ca->tcp_cwnd = 0;
106 	ca->found = 0;
164 	struct bictcp *ca = inet_csk_ca(sk);
166 	ca->round_start = ca->last_ack = bictcp_clock_us(sk);
167 	ca->end_seq = tp->snd_nxt;
168 	ca->curr_rtt = ~0U;
169 	ca->sample_cnt = 0;
176 	struct bictcp *ca = inet_csk_ca(sk);
178 	bictcp_reset(ca);
192 		struct bictcp *ca = inet_csk_ca(sk);
201 		if (ca->epoch_start && delta > 0) {
202 			ca->epoch_start += delta;
203 			if (after(ca->epoch_start, now))
204 				ca->epoch_start = now;
266 static __always_inline void bictcp_update(struct bictcp *ca, __u32 cwnd,
272 	ca->ack_cnt += acked;	/* count the number of ACKed packets */
274 	if (ca->last_cwnd == cwnd &&
275 	    (__s32)(tcp_jiffies32 - ca->last_time) <= HZ / 32)
278 	/* The CUBIC function can update ca->cnt at most once per jiffy.
279 	 * On all cwnd reduction events, ca->epoch_start is set to 0,
280 	 * which will force a recalculation of ca->cnt.
282 	if (ca->epoch_start && tcp_jiffies32 == ca->last_time)
285 	ca->last_cwnd = cwnd;
286 	ca->last_time = tcp_jiffies32;
288 	if (ca->epoch_start == 0) {
289 		ca->epoch_start = tcp_jiffies32;	/* record beginning */
290 		ca->ack_cnt = acked;			/* start counting */
291 		ca->tcp_cwnd = cwnd;			/* syn with cubic */
293 		if (ca->last_max_cwnd <= cwnd) {
294 			ca->bic_K = 0;
295 			ca->bic_origin_point = cwnd;
300 			ca->bic_K = cubic_root(cube_factor
301 					       * (ca->last_max_cwnd - cwnd));
302 			ca->bic_origin_point = ca->last_max_cwnd;
320 	t = (__s32)(tcp_jiffies32 - ca->epoch_start) * USEC_PER_JIFFY;
321 	t += ca->delay_min;
326 	if (t < ca->bic_K)		/* t - K */
327 		offs = ca->bic_K - t;
329 		offs = t - ca->bic_K;
333 	if (t < ca->bic_K)                            /* below origin*/
334 		bic_target = ca->bic_origin_point - delta;
336 		bic_target = ca->bic_origin_point + delta;
340 		ca->cnt = cwnd / (bic_target - cwnd);
342 		ca->cnt = 100 * cwnd;              /* very small increment*/
349 	if (ca->last_max_cwnd == 0 && ca->cnt > 20)
350 		ca->cnt = 20;	/* increase cwnd 5% per RTT */
360 		if (ca->ack_cnt > delta && delta) {
361 			n = ca->ack_cnt / delta;
362 			ca->ack_cnt -= n * delta;
363 			ca->tcp_cwnd += n;
366 		if (ca->tcp_cwnd > cwnd) {	/* if bic is slower than tcp */
367 			delta = ca->tcp_cwnd - cwnd;
369 			if (ca->cnt > max_cnt)
370 				ca->cnt = max_cnt;
377 	ca->cnt = max(ca->cnt, 2U);
384 	struct bictcp *ca = inet_csk_ca(sk);
390 		if (hystart && after(ack, ca->end_seq))
396 	bictcp_update(ca, tp->snd_cwnd, acked);
397 	tcp_cong_avoid_ai(tp, ca->cnt, acked);
403 	struct bictcp *ca = inet_csk_ca(sk);
405 	ca->epoch_start = 0;	/* end of epoch */
408 	if (tp->snd_cwnd < ca->last_max_cwnd && fast_convergence)
409 		ca->last_max_cwnd = (tp->snd_cwnd * (BICTCP_BETA_SCALE + beta))
412 		ca->last_max_cwnd = tp->snd_cwnd;
429  * slow start we begin with small TSO packets and ca->delay_min would
450 	struct bictcp *ca = inet_csk_ca(sk);
457 		if ((__s32)(now - ca->last_ack) <= hystart_ack_delta_us) {
458 			ca->last_ack = now;
460 			threshold = ca->delay_min + hystart_ack_delay(sk);
463 			 * ca->delay_min/2.
470 			if ((__s32)(now - ca->round_start) > threshold) {
471 				ca->found = 1;
479 		if (ca->curr_rtt > delay)
480 			ca->curr_rtt = delay;
481 		if (ca->sample_cnt < HYSTART_MIN_SAMPLES) {
482 			ca->sample_cnt++;
484 			if (ca->curr_rtt > ca->delay_min +
485 			    HYSTART_DELAY_THRESH(ca->delay_min >> 3)) {
486 				ca->found = 1;
499 	struct bictcp *ca = inet_csk_ca(sk);
508 	if (ca->epoch_start && (__s32)(tcp_jiffies32 - ca->epoch_start) < HZ)
516 	if (ca->delay_min == 0 || ca->delay_min > delay)
517 		ca->delay_min = delay;
520 	if (!ca->found && tcp_in_slow_start(tp) && hystart &&