langspielplatte/tcp-roccet-kernel-module
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Adjusts sruct size and refactor of code.

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This commit is contained in:
Lukas Prause
2026-07-20 14:57:20 +02:00
parent a6356c3297
commit b651be77b3
3 changed files with 341 additions and 321 deletions
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README.md
+1 -1
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@@ -7,7 +7,7 @@ A peer-reviewed [paper on TCP ROCCET](https://opendl.ifip-tc6.org/db/conf/wons/w
### Versions ### Versions
- latest on master branch - latest on master branch (requires kernel version 6.15 or higher)
- Improved min RTT probing - Improved min RTT probing
- Packet pacing - Packet pacing
- Code refactor - Code refactor
tcp_roccet.c
+101 -77
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@@ -45,14 +45,13 @@
* this behaves the same as the original Reno. * this behaves the same as the original Reno.
*/ */
#include "tcp_roccet.h" #include "linux/limits.h"
#include <linux/btf.h>
#include <linux/btf_ids.h>
#include <linux/math64.h> #include <linux/math64.h>
#include <linux/mm.h> #include <linux/mm.h>
#include <linux/module.h> #include <linux/module.h>
#include <linux/moduleparam.h> #include <linux/moduleparam.h>
#include <net/tcp.h> #include <net/tcp.h>
#include "tcp_roccet.h"
/* Scale factor beta calculation (max_cwnd = snd_cwnd * beta) */ /* Scale factor beta calculation (max_cwnd = snd_cwnd * beta) */
#define BICTCP_BETA_SCALE 1024 #define BICTCP_BETA_SCALE 1024
@@ -109,11 +108,13 @@ static __always_inline void roccettcp_reset(struct roccettcp *ca)
ca->ece_received = false; ca->ece_received = false;
ca->roccet_last_event_time_us = 0; ca->roccet_last_event_time_us = 0;
ca->ack_rate.last_rate = 0; ca->ack_rate_last_rate = 0;
/* Initialize to current time to avoid overflow in ack rate calculation */ /* Initialize to current time to avoid an
ca->ack_rate.last_rate_time = jiffies_to_usecs(tcp_jiffies32); * overflow in the ack rate calculation
ca->ack_rate.curr_rate = 0; */
ca->ack_rate.cnt = 0; ca->ack_rate_last_rate_time = jiffies_to_usecs(tcp_jiffies32);
ca->ack_rate_curr_rate = 0;
ca->ack_rate_cnt = 0;
/* Start state is LAUNCH */ /* Start state is LAUNCH */
ca->state = LAUNCH; ca->state = LAUNCH;
@@ -138,7 +139,8 @@ static __always_inline void update_min_rtt(struct sock *sk)
/* Probe for the min RTT in ROCCET_NEXT_MIN_RTT_PROBE seconds /* Probe for the min RTT in ROCCET_NEXT_MIN_RTT_PROBE seconds
* if no other update occurs. * if no other update occurs.
*/ */
ca->next_min_rtt_probe = jiffies_to_usecs(tcp_jiffies32) + ca->next_min_rtt_probe =
jiffies_to_usecs(tcp_jiffies32) +
ROCCET_NEXT_MIN_RTT_PROBE * USEC_PER_MSEC; ROCCET_NEXT_MIN_RTT_PROBE * USEC_PER_MSEC;
} }
} }
@@ -147,9 +149,9 @@ static __always_inline void update_min_rtt(struct sock *sk)
*/ */
static __always_inline s32 get_ack_rate_diff(struct roccettcp *ca) static __always_inline s32 get_ack_rate_diff(struct roccettcp *ca)
{ {
if (ca->ack_rate.curr_rate < ca->ack_rate.last_rate) if (ca->ack_rate_curr_rate < ca->ack_rate_last_rate)
return 0; return 0;
return (s32)(ca->ack_rate.curr_rate - ca->ack_rate.last_rate); return (s32)(ca->ack_rate_curr_rate - ca->ack_rate_last_rate);
} }
/* Update ack rate sampled by 100ms. /* Update ack rate sampled by 100ms.
@@ -159,26 +161,34 @@ static __always_inline void update_ack_rate(struct sock *sk, u32 acked, u32 now)
struct roccettcp *ca = inet_csk_ca(sk); struct roccettcp *ca = inet_csk_ca(sk);
s32 interval = USEC_PER_MSEC * 100; s32 interval = USEC_PER_MSEC * 100;
s32 time_delta = (s32)(ca->ack_rate.last_rate_time - now); s32 time_delta = (s32)(ca->ack_rate_last_rate_time - now);
const s32 idle_threshold = USEC_PER_SEC * 2; const s32 idle_threshold = USEC_PER_SEC * 2;
// Check if the time has arrived in the new interval // Check if the time has arrived in the new interval
if (time_delta < -interval) { if (time_delta < -interval) {
// Check if the connection was idle for X seconds (e.g. no ACK for X seconds) /* Check if the connection was idle for X seconds
* (e.g. no ACK for X seconds)
*/
if (time_delta < -idle_threshold) { if (time_delta < -idle_threshold) {
// Reset ack counting as if a new connection was created /* Reset ack counting as if a new
ca->ack_rate.last_rate = 0; * connection was created
ca->ack_rate.last_rate_time = jiffies_to_usecs(tcp_jiffies32); */
ca->ack_rate.curr_rate = 0; ca->ack_rate_last_rate = 0;
ca->ack_rate.cnt = 0; ca->ack_rate_last_rate_time =
jiffies_to_usecs(tcp_jiffies32);
ca->ack_rate_curr_rate = 0;
ca->ack_rate_cnt = 0;
} else { } else {
ca->ack_rate.last_rate_time = now; ca->ack_rate_last_rate_time = now;
ca->ack_rate.last_rate = ca->ack_rate.curr_rate; ca->ack_rate_last_rate = ca->ack_rate_curr_rate;
ca->ack_rate.curr_rate = ca->ack_rate.cnt; ca->ack_rate_curr_rate = ca->ack_rate_cnt;
ca->ack_rate.cnt = acked; // start counting for the new interval ca->ack_rate_cnt =
acked; // start counting for the new interval
} }
} else { } else {
ca->ack_rate.cnt += acked; // Cap the ack count to avoid overflow
ca->ack_rate_cnt = min_t(u32, ca->ack_rate_cnt + acked,
U16_MAX);
} }
} }
@@ -217,7 +227,8 @@ static __always_inline void update_srrtt(struct sock *sk)
// (1 - alpha) * srRTT + alpha * rRTT // (1 - alpha) * srRTT + alpha * rRTT
ca->curr_srrtt = ((100 - ROCCET_ALPHA_TIMES_100) * ca->curr_srrtt + ca->curr_srrtt = ((100 - ROCCET_ALPHA_TIMES_100) * ca->curr_srrtt +
ROCCET_ALPHA_TIMES_100 * rrtt) / 100; ROCCET_ALPHA_TIMES_100 * rrtt) /
100;
} }
/* Do a ROCCET congestion event. /* Do a ROCCET congestion event.
@@ -233,11 +244,11 @@ static __always_inline void roccet_congestion_event(struct sock *sk, u32 now)
/*Set W_max only if the current cwnd is larger */ /*Set W_max only if the current cwnd is larger */
if (tcp_snd_cwnd(tp) > ca->last_max_cwnd) if (tcp_snd_cwnd(tp) > ca->last_max_cwnd)
ca->last_max_cwnd = tcp_snd_cwnd(tp); ca->last_max_cwnd = tcp_snd_cwnd(tp);
tcp_snd_cwnd_set(tp, min(tp->snd_cwnd_clamp, tcp_snd_cwnd_set(tp,
max((tcp_snd_cwnd(tp) * beta) / min(tp->snd_cwnd_clamp,
BICTCP_BETA_SCALE, 2U))); max((tcp_snd_cwnd(tp) * beta)
/ BICTCP_BETA_SCALE, 2U)));
tp->snd_ssthresh = tcp_snd_cwnd(tp); tp->snd_ssthresh = tcp_snd_cwnd(tp);
} }
/* Do minimum RTT probing. /* Do minimum RTT probing.
@@ -253,12 +264,12 @@ static __always_inline void roccet_min_rtt_probe(struct sock *sk, u32 now)
return; return;
/* Start of min RTT probing*/ /* Start of min RTT probing*/
if(ca->probe_min_rtt_until == 0){ if (ca->probe_min_rtt_until == 0) {
/* Probe 1*RTT or at least 200ms */ /* Probe 1*RTT or at least 200ms */
interval = max(200 * USEC_PER_MSEC, ca->curr_rtt); interval = max(200 * USEC_PER_MSEC, ca->curr_rtt);
/* This is to handle deep shared buffers with loss-based /* This is to handle deep shared buffers with loss-based
* congestion control like CUBIC. If the the cwnd is not limited * congestion control like CUBIC. If the cwnd is not limited
* by the application but falsely detected (see ROCCET paper), * by the application but falsely detected (see ROCCET paper),
* we have to empty the pipe more. * we have to empty the pipe more.
* If the limit detection is correct this will cause no harm * If the limit detection is correct this will cause no harm
@@ -285,18 +296,18 @@ static __always_inline void roccet_min_rtt_probe(struct sock *sk, u32 now)
ca->curr_min_rtt = ~0U; ca->curr_min_rtt = ~0U;
/* Refill the pipe after probing. /* Refill the pipe after probing.
* To this end we need the previous cwnd over the * To this end we need the previous cwnd over
* the probing interval. * the probing interval.
*/ */
ca->refill_until = ca->probe_min_rtt_until + interval; ca->refill_until = ca->probe_min_rtt_until + interval;
}else if(before(now, ca->refill_until)){ } else if (before(now, ca->refill_until)) {
/* Reset cwnd and refill the pipe. */ /* Reset cwnd and refill the pipe. */
if(ca->state != RTT_PROBE_REFILL){ if (ca->state != RTT_PROBE_REFILL) {
tcp_snd_cwnd_set(tp, ca->cwnd_before_min_rtt_probe); tcp_snd_cwnd_set(tp, ca->cwnd_before_min_rtt_probe);
tcp_sk(sk)->snd_ssthresh = tcp_snd_cwnd(tp); tcp_sk(sk)->snd_ssthresh = tcp_snd_cwnd(tp);
ca->state = RTT_PROBE_REFILL; ca->state = RTT_PROBE_REFILL;
} }
}else{ } else {
/* End min RTT probing phase. */ /* End min RTT probing phase. */
ca->probe_min_rtt_until = 0; ca->probe_min_rtt_until = 0;
ca->state = ORBITER; ca->state = ORBITER;
@@ -492,8 +503,7 @@ tcp_friendliness:
ca->cnt = max(ca->cnt, 2U); ca->cnt = max(ca->cnt, 2U);
} }
static void roccettcp_cong_avoid(struct sock *sk, u32 ack, static void roccettcp_cong_avoid(struct sock *sk, u32 ack, u32 acked)
u32 acked)
{ {
struct tcp_sock *tp = tcp_sk(sk); struct tcp_sock *tp = tcp_sk(sk);
struct roccettcp *ca = inet_csk_ca(sk); struct roccettcp *ca = inet_csk_ca(sk);
@@ -505,7 +515,7 @@ static void roccettcp_cong_avoid(struct sock *sk, u32 ack,
u32 jitter; u32 jitter;
u32 send, received; u32 send, received;
if(ca->state == LAUNCH){ if (ca->state == LAUNCH) {
/* LAUNCH: Detect an exit point for tcp slow start /* LAUNCH: Detect an exit point for tcp slow start
* in networks with large buffers of multiple BDP * in networks with large buffers of multiple BDP
* Like in cellular networks (5G, ...). * Like in cellular networks (5G, ...).
@@ -517,9 +527,12 @@ static void roccettcp_cong_avoid(struct sock *sk, u32 ack,
!tcp_is_cwnd_limited(sk)) { !tcp_is_cwnd_limited(sk)) {
ca->epoch_start = 0; ca->epoch_start = 0;
/* Handle initial slow start. Here occur most bufferbloat */ /* Handle initial slow start.
* Most bufferbloat occurs here
*/
if (tp->snd_ssthresh == TCP_INFINITE_SSTHRESH) { if (tp->snd_ssthresh == TCP_INFINITE_SSTHRESH) {
tcp_sk(sk)->snd_ssthresh = tcp_snd_cwnd(tp) / 2; tcp_sk(sk)->snd_ssthresh = tcp_snd_cwnd(tp)
/ 2;
/* since this is the initial slow start, /* since this is the initial slow start,
* the min cwnd won't be 1, so the window * the min cwnd won't be 1, so the window
* can't be set to 0 by accident. * can't be set to 0 by accident.
@@ -531,7 +544,8 @@ static void roccettcp_cong_avoid(struct sock *sk, u32 ack,
TCP_INIT_CWND)); TCP_INIT_CWND));
} else { } else {
tcp_sk(sk)->snd_ssthresh = tcp_sk(sk)->snd_ssthresh =
tcp_snd_cwnd(tp) - (tcp_snd_cwnd(tp) / 3); tcp_snd_cwnd(tp) -
(tcp_snd_cwnd(tp) / 3);
tcp_snd_cwnd_set(tp, tcp_snd_cwnd(tp) - tcp_snd_cwnd_set(tp, tcp_snd_cwnd(tp) -
(tcp_snd_cwnd(tp) / 3)); (tcp_snd_cwnd(tp) / 3));
} }
@@ -543,7 +557,7 @@ static void roccettcp_cong_avoid(struct sock *sk, u32 ack,
if (!acked) if (!acked)
return; return;
}else if(ca->state == ORBITER){ } else if (ca->state == ORBITER) {
/* ORBITER: Increase the cwnd by using the CUBIC /* ORBITER: Increase the cwnd by using the CUBIC
* cwnd growth function, if no roccet congestion * cwnd growth function, if no roccet congestion
* event is detechted. * event is detechted.
@@ -558,19 +572,20 @@ static void roccettcp_cong_avoid(struct sock *sk, u32 ack,
if (ca->next_srrtt_check == 0) if (ca->next_srrtt_check == 0)
ca->next_srrtt_check = now + 5 * ca->curr_rtt; ca->next_srrtt_check = now + 5 * ca->curr_rtt;
/* Calculate if more bytes was send than reveived /* Calculate if more bytes was send than received
* in the time interval. * in the time interval.
*/ */
if (tp->snd_nxt < ca->interval_snd_seq_start){ if (before(tp->snd_nxt, ca->interval_snd_seq_start)) {
/* We had a wrap around in seq no counter */ /* We had a wrap around in seq no counter */
send = (~0U - ca->interval_snd_seq_start + tp->snd_nxt); send = (~0U - ca->interval_snd_seq_start + tp->snd_nxt);
}else{ } else {
send = (tp->snd_nxt - ca->interval_snd_seq_start); send = (tp->snd_nxt - ca->interval_snd_seq_start);
} }
if (tp->snd_una < ca->interval_una_seq_start){ if (before(tp->snd_una, ca->interval_una_seq_start)) {
/* We had a wrap around in seq no counter */ /* We had a wrap around in seq no counter */
received = (~0U - ca->interval_una_seq_start + tp->snd_una); received = (~0U - ca->interval_una_seq_start +
}else{ tp->snd_una);
} else {
received = (tp->snd_una - ca->interval_una_seq_start); received = (tp->snd_una - ca->interval_una_seq_start);
} }
@@ -578,7 +593,9 @@ static void roccettcp_cong_avoid(struct sock *sk, u32 ack,
* We do this to avoid a false positive evaluation due * We do this to avoid a false positive evaluation due
* to delays caused by jitter or scheduling. * to delays caused by jitter or scheduling.
*/ */
send_more_than_acked = send > received + ((tcp_snd_cwnd(tp) * tp->mss_cache) / 100 ); send_more_than_acked =
send >
received + ((tcp_snd_cwnd(tp) * tp->mss_cache) / 100);
/* Check if it's time to evaluate the srRTT */ /* Check if it's time to evaluate the srRTT */
if ((s32)(ca->next_srrtt_check - now) < 0) { if ((s32)(ca->next_srrtt_check - now) < 0) {
@@ -603,17 +620,19 @@ static void roccettcp_cong_avoid(struct sock *sk, u32 ack,
/* The srRTT exceeds the upper bound if bufferbloat happens. /* The srRTT exceeds the upper bound if bufferbloat happens.
* Here, we want to reduce the cwnd and drain the buffer. * Here, we want to reduce the cwnd and drain the buffer.
*/ */
if (ca->curr_srrtt > roccet_xj && evaluate_srrtt && send_more_than_acked) { if (ca->curr_srrtt > roccet_xj && evaluate_srrtt &&
send_more_than_acked) {
roccet_congestion_event(sk, now); roccet_congestion_event(sk, now);
return; return;
} }
/* Terminates this function if cwnd is not fully utilized. /* Terminates this function if cwnd is not fully utilized.
* In mobile networks like 5G, this termination causes the cwnd to be * In mobile networks like 5G, this termination causes the
* frozen at an excessively high value. This is because slow start or * cwnd to be frozen at an excessively high value. This is
* HyStart massively exceed the available bandwidth and leave the cwnd * because slow start or HyStart massively exceed the available
* at an excessively high value. The cwnd cannot therefore be fully * bandwidth and leave the cwnd at an excessively high value.
* utilized because it is limited by the connection capacity. * The cwnd cannot therefore be fully utilized because it is
* limited by the connection capacity.
*/ */
if (!tcp_is_cwnd_limited(sk) || send_more_than_acked) if (!tcp_is_cwnd_limited(sk) || send_more_than_acked)
return; return;
@@ -627,9 +646,9 @@ static u32 roccettcp_recalc_ssthresh(struct sock *sk)
{ {
const struct tcp_sock *tp = tcp_sk(sk); const struct tcp_sock *tp = tcp_sk(sk);
struct roccettcp *ca = inet_csk_ca(sk); struct roccettcp *ca = inet_csk_ca(sk);
u32 cwnd; u32 cwnd = tcp_snd_cwnd(tp);
/* If a loss/ECN occurs in the refill pahse of min RTT probing /* If a loss/ECN occurs in the refill phase of min RTT probing
* we reduce the cwnd and abort the refill. * we reduce the cwnd and abort the refill.
*/ */
if (ca->state == RTT_PROBE_REFILL) if (ca->state == RTT_PROBE_REFILL)
@@ -643,7 +662,7 @@ static u32 roccettcp_recalc_ssthresh(struct sock *sk)
* congestion was caused by the cwnd value before min * congestion was caused by the cwnd value before min
* RTT probing. * RTT probing.
*/ */
if (ca->state == RTT_PROBE){ if (ca->state == RTT_PROBE) {
/* Handle ECN as cubic congestion event in min /* Handle ECN as cubic congestion event in min
* RTT probe. * RTT probe.
*/ */
@@ -660,7 +679,9 @@ static u32 roccettcp_recalc_ssthresh(struct sock *sk)
ca->last_max_cwnd = cwnd; ca->last_max_cwnd = cwnd;
cwnd = ca->cwnd_before_min_rtt_probe; cwnd = ca->cwnd_before_min_rtt_probe;
ca->cwnd_before_min_rtt_probe = max((cwnd * beta) / BICTCP_BETA_SCALE, 2U); ca->cwnd_before_min_rtt_probe =
max((cwnd * beta) / BICTCP_BETA_SCALE, 2U);
return cwnd; return cwnd;
} }
@@ -698,17 +719,15 @@ static void roccettcp_state(struct sock *sk, u8 new_state)
struct roccettcp *ca = inet_csk_ca(sk); struct roccettcp *ca = inet_csk_ca(sk);
struct tcp_sock *tp = tcp_sk(sk); struct tcp_sock *tp = tcp_sk(sk);
if (new_state == TCP_CA_Loss){ if (new_state == TCP_CA_Loss) {
roccettcp_reset(ca); roccettcp_reset(ca);
} } else if (new_state == TCP_CA_Recovery) {
else if(new_state == TCP_CA_Recovery){
tcp_sk(sk)->snd_ssthresh = roccettcp_recalc_ssthresh(sk); tcp_sk(sk)->snd_ssthresh = roccettcp_recalc_ssthresh(sk);
tcp_snd_cwnd_set(tp, tcp_sk(sk)->snd_ssthresh); tcp_snd_cwnd_set(tp, tcp_sk(sk)->snd_ssthresh);
} }
} }
static void roccettcp_acked(struct sock *sk, static void roccettcp_acked(struct sock *sk, const struct ack_sample *sample)
const struct ack_sample *sample)
{ {
struct roccettcp *ca = inet_csk_ca(sk); struct roccettcp *ca = inet_csk_ca(sk);
@@ -747,7 +766,9 @@ static void roccet_in_ack_event(struct sock *sk, u32 flags)
ca->ece_received = true; ca->ece_received = true;
} }
__bpf_kfunc static void roccet_control(struct sock *sk, u32 ack, int flag, const struct rate_sample *rs) { static void roccet_control(struct sock *sk, u32 ack, int flag,
const struct rate_sample *rs)
{
struct tcp_sock *tp = tcp_sk(sk); struct tcp_sock *tp = tcp_sk(sk);
struct roccettcp *ca = inet_csk_ca(sk); struct roccettcp *ca = inet_csk_ca(sk);
@@ -760,23 +781,23 @@ __bpf_kfunc static void roccet_control(struct sock *sk, u32 ack, int flag, const
update_srrtt(sk); update_srrtt(sk);
/* Set values for send and receive rate */ /* Set values for send and receive rate */
if (ca->interval_snd_seq_start == 0){ if (ca->interval_snd_seq_start == 0) {
ca->interval_snd_seq_start = tp->snd_nxt; ca->interval_snd_seq_start = tp->snd_nxt;
ca->interval_una_seq_start = tp->snd_una; ca->interval_una_seq_start = tp->snd_una;
} }
/* Update roccet state */ /* Update roccet state */
if(tcp_in_slow_start(tp)){ if (tcp_in_slow_start(tp)) {
ca->state = LAUNCH; ca->state = LAUNCH;
}else if((s32) now - ca->roccet_last_event_time_us <= 100 * USEC_PER_MSEC){ } else if ((s32)now - ca->roccet_last_event_time_us <=
100 * USEC_PER_MSEC) {
ca->state = DRAIN; ca->state = DRAIN;
} } else if (after(now, ca->next_min_rtt_probe) ||
else if(after(now, ca->next_min_rtt_probe) || ca->state == RTT_PROBE || ca->state == RTT_PROBE_REFILL){ ca->state == RTT_PROBE || ca->state == RTT_PROBE_REFILL) {
if(ca->state != RTT_PROBE_REFILL) if (ca->state != RTT_PROBE_REFILL)
ca->state = RTT_PROBE; ca->state = RTT_PROBE;
roccet_min_rtt_probe(sk, now); roccet_min_rtt_probe(sk, now);
} } else {
else{
ca->state = ORBITER; ca->state = ORBITER;
} }
@@ -790,7 +811,7 @@ __bpf_kfunc static void roccet_control(struct sock *sk, u32 ack, int flag, const
roccettcp_cong_avoid(sk, ack, rs->acked_sacked); roccettcp_cong_avoid(sk, ack, rs->acked_sacked);
/* Adjust pacing rate. The code here is similar to the /* Adjust pacing rate. The code here is similar to the
* pacing rate adjustemnts in tcp_input.c tcp_cong_control(). * pacing rate adjustments in tcp_input.c tcp_cong_control().
* In LAUNCH (slow start) we want a pacing of 200% and * In LAUNCH (slow start) we want a pacing of 200% and
* in ORBITER (congestion avoidance) we adjust the pacing * in ORBITER (congestion avoidance) we adjust the pacing
* to 100% and do not use the sysctl_tcp_pacing_ca_ratio. * to 100% and do not use the sysctl_tcp_pacing_ca_ratio.
@@ -803,14 +824,17 @@ __bpf_kfunc static void roccet_control(struct sock *sk, u32 ack, int flag, const
* In Slow Start [1], set sk_pacing_rate to 200 % the current rate. * In Slow Start [1], set sk_pacing_rate to 200 % the current rate.
* In Congestion Avoidance phase, set it to 120 % the current rate. * In Congestion Avoidance phase, set it to 120 % the current rate.
* *
* [1] : Normal Slow Start condition is (tp->snd_cwnd < tp->snd_ssthresh) * [1]: Normal Slow Start cond is (tp->snd_cwnd < tp->snd_ssthresh)
* If snd_cwnd >= (tp->snd_ssthresh / 2), we are approaching * If snd_cwnd >= (tp->snd_ssthresh / 2), we are approaching
* end of slow start and should slow down. * end of slow start and should slow down.
*/ */
if (tcp_snd_cwnd(tp) < tp->snd_ssthresh / 2) if (tcp_snd_cwnd(tp) < tp->snd_ssthresh / 2)
rate *= READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_pacing_ss_ratio); rate *= READ_ONCE
(sock_net(sk)->ipv4.sysctl_tcp_pacing_ss_ratio);
else else
/* Pacing rate of 100% (instead of ipv4.sysctl_tcp_pacing_ca_ratio) */ /* Pacing rate of 100%
* (instead of ipv4.sysctl_tcp_pacing_ca_ratio)
*/
rate *= 100; rate *= 100;
rate *= max(tcp_snd_cwnd(tp), tp->packets_out); rate *= max(tcp_snd_cwnd(tp), tp->packets_out);
@@ -819,7 +843,7 @@ __bpf_kfunc static void roccet_control(struct sock *sk, u32 ack, int flag, const
do_div(rate, tp->srtt_us); do_div(rate, tp->srtt_us);
/* WRITE_ONCE() is needed because sch_fq fetches sk_pacing_rate /* WRITE_ONCE() is needed because sch_fq fetches sk_pacing_rate
* without any lock. We want to make sure compiler wont store * without any lock. We want to make sure compiler won't store
* intermediate values in this location. * intermediate values in this location.
*/ */
WRITE_ONCE(sk->sk_pacing_rate, WRITE_ONCE(sk->sk_pacing_rate,
tcp_roccet.h
+11 -15
View File
@@ -7,7 +7,7 @@
#include <linux/math64.h> #include <linux/math64.h>
/* State in which roccet currently opperates */ /* State in which roccet currently operates */
enum roccet_state { enum roccet_state {
LAUNCH, LAUNCH,
ORBITER, ORBITER,
@@ -16,14 +16,6 @@ enum roccet_state {
DRAIN DRAIN
}; };
/* TCP ROCCET helper type, storing data related to ack counting */
struct ack_rate {
u32 last_rate; /* Last ACK-rate */
u32 last_rate_time; /* Timestamp of the last ACK-rate */
u32 curr_rate; /* Current ACK-rate */
u32 cnt; /* Used for counting acks */
};
/* TCP ROCCET struct based on the original BICTCP struct with /* TCP ROCCET struct based on the original BICTCP struct with
* additions specific to the ROCCET-Algorithm. * additions specific to the ROCCET-Algorithm.
*/ */
@@ -42,10 +34,7 @@ struct roccettcp {
u32 tcp_cwnd; /* estimated tcp cwnd */ u32 tcp_cwnd; /* estimated tcp cwnd */
u32 curr_rtt; /* last sample rtt of current round */ u32 curr_rtt; /* last sample rtt of current round */
u32 roccet_last_event_time_us; /* The last time ROCCET was u32 roccet_last_event_time_us; /* The last time ROCCET was triggered */
* triggered
*/
bool ece_received; /* Set to true if an ECE bit was received */
u32 curr_min_rtt; /* The current observed minRTT */ u32 curr_min_rtt; /* The current observed minRTT */
u32 next_min_rtt_probe; /* Next time to probe the minRTT */ u32 next_min_rtt_probe; /* Next time to probe the minRTT */
u32 probe_min_rtt_until; /* End of minRTT probing period */ u32 probe_min_rtt_until; /* End of minRTT probing period */
@@ -53,13 +42,20 @@ struct roccettcp {
u32 cwnd_before_min_rtt_probe; /* cwnd before min RTT probeing */ u32 cwnd_before_min_rtt_probe; /* cwnd before min RTT probeing */
u32 curr_srrtt; /* srRTT calculated based on the latest ACK */ u32 curr_srrtt; /* srRTT calculated based on the latest ACK */
u32 next_srrtt_check; /* Next check for srRTT */ u32 next_srrtt_check; /* Next check for srRTT */
struct ack_rate ack_rate; /* The last and the current ACK rate */
u32 last_rtt; /* sample rtt of previous round. u32 last_rtt; /* sample rtt of previous round.
* Used for jitter calculation * Used for jitter calculation
*/ */
enum roccet_state state; /* State in which roccet currently opperates */
u32 interval_snd_seq_start; u32 interval_snd_seq_start;
u32 interval_una_seq_start; u32 interval_una_seq_start;
u32 ack_rate_last_rate_time; /* Timestamp of the last ACK-rate */
u16 ack_rate_last_rate; /* Last ACK-rate */
u16 ack_rate_curr_rate; /* Current ACK-rate */
u16 ack_rate_cnt; /* Used for counting acks */
bool ece_received; /* Set to true if an ECE bit was received */
enum roccet_state state; /* State in which roccet currently operates */
}; };
#endif /* __TCP_ROCCET_H */ #endif /* __TCP_ROCCET_H */