diff options
Diffstat (limited to 'net/ipv4/tcp_htcp.c')
-rw-r--r-- | net/ipv4/tcp_htcp.c | 67 |
1 files changed, 38 insertions, 29 deletions
diff --git a/net/ipv4/tcp_htcp.c b/net/ipv4/tcp_htcp.c index 753987a..1020eb4 100644 --- a/net/ipv4/tcp_htcp.c +++ b/net/ipv4/tcp_htcp.c @@ -10,22 +10,23 @@ #include <linux/module.h> #include <net/tcp.h> -#define ALPHA_BASE (1<<7) /* 1.0 with shift << 7 */ -#define BETA_MIN (1<<6) /* 0.5 with shift << 7 */ +#define ALPHA_BASE (1<<7) /* 1.0 with shift << 7 */ +#define BETA_MIN (1<<6) /* 0.5 with shift << 7 */ #define BETA_MAX 102 /* 0.8 with shift << 7 */ -static int use_rtt_scaling = 1; +static int use_rtt_scaling __read_mostly = 1; module_param(use_rtt_scaling, int, 0644); MODULE_PARM_DESC(use_rtt_scaling, "turn on/off RTT scaling"); -static int use_bandwidth_switch = 1; +static int use_bandwidth_switch __read_mostly = 1; module_param(use_bandwidth_switch, int, 0644); MODULE_PARM_DESC(use_bandwidth_switch, "turn on/off bandwidth switcher"); struct htcp { u32 alpha; /* Fixed point arith, << 7 */ u8 beta; /* Fixed point arith, << 7 */ - u8 modeswitch; /* Delay modeswitch until we had at least one congestion event */ + u8 modeswitch; /* Delay modeswitch + until we had at least one congestion event */ u16 pkts_acked; u32 packetcount; u32 minRTT; @@ -44,14 +45,14 @@ struct htcp { u32 lasttime; }; -static inline u32 htcp_cong_time(struct htcp *ca) +static inline u32 htcp_cong_time(const struct htcp *ca) { return jiffies - ca->last_cong; } -static inline u32 htcp_ccount(struct htcp *ca) +static inline u32 htcp_ccount(const struct htcp *ca) { - return htcp_cong_time(ca)/ca->minRTT; + return htcp_cong_time(ca) / ca->minRTT; } static inline void htcp_reset(struct htcp *ca) @@ -67,10 +68,12 @@ static u32 htcp_cwnd_undo(struct sock *sk) { const struct tcp_sock *tp = tcp_sk(sk); struct htcp *ca = inet_csk_ca(sk); + ca->last_cong = ca->undo_last_cong; ca->maxRTT = ca->undo_maxRTT; ca->old_maxB = ca->undo_old_maxB; - return max(tp->snd_cwnd, (tp->snd_ssthresh<<7)/ca->beta); + + return max(tp->snd_cwnd, (tp->snd_ssthresh << 7) / ca->beta); } static inline void measure_rtt(struct sock *sk) @@ -78,17 +81,19 @@ static inline void measure_rtt(struct sock *sk) const struct inet_connection_sock *icsk = inet_csk(sk); const struct tcp_sock *tp = tcp_sk(sk); struct htcp *ca = inet_csk_ca(sk); - u32 srtt = tp->srtt>>3; + u32 srtt = tp->srtt >> 3; /* keep track of minimum RTT seen so far, minRTT is zero at first */ if (ca->minRTT > srtt || !ca->minRTT) ca->minRTT = srtt; /* max RTT */ - if (icsk->icsk_ca_state == TCP_CA_Open && tp->snd_ssthresh < 0xFFFF && htcp_ccount(ca) > 3) { + if (icsk->icsk_ca_state == TCP_CA_Open + && tp->snd_ssthresh < 0xFFFF && htcp_ccount(ca) > 3) { if (ca->maxRTT < ca->minRTT) ca->maxRTT = ca->minRTT; - if (ca->maxRTT < srtt && srtt <= ca->maxRTT+msecs_to_jiffies(20)) + if (ca->maxRTT < srtt + && srtt <= ca->maxRTT + msecs_to_jiffies(20)) ca->maxRTT = srtt; } } @@ -116,15 +121,16 @@ static void measure_achieved_throughput(struct sock *sk, u32 pkts_acked) ca->packetcount += pkts_acked; - if (ca->packetcount >= tp->snd_cwnd - (ca->alpha>>7? : 1) - && now - ca->lasttime >= ca->minRTT - && ca->minRTT > 0) { - __u32 cur_Bi = ca->packetcount*HZ/(now - ca->lasttime); + if (ca->packetcount >= tp->snd_cwnd - (ca->alpha >> 7 ? : 1) + && now - ca->lasttime >= ca->minRTT + && ca->minRTT > 0) { + __u32 cur_Bi = ca->packetcount * HZ / (now - ca->lasttime); + if (htcp_ccount(ca) <= 3) { /* just after backoff */ ca->minB = ca->maxB = ca->Bi = cur_Bi; } else { - ca->Bi = (3*ca->Bi + cur_Bi)/4; + ca->Bi = (3 * ca->Bi + cur_Bi) / 4; if (ca->Bi > ca->maxB) ca->maxB = ca->Bi; if (ca->minB > ca->maxB) @@ -142,7 +148,7 @@ static inline void htcp_beta_update(struct htcp *ca, u32 minRTT, u32 maxRTT) u32 old_maxB = ca->old_maxB; ca->old_maxB = ca->maxB; - if (!between(5*maxB, 4*old_maxB, 6*old_maxB)) { + if (!between(5 * maxB, 4 * old_maxB, 6 * old_maxB)) { ca->beta = BETA_MIN; ca->modeswitch = 0; return; @@ -150,7 +156,7 @@ static inline void htcp_beta_update(struct htcp *ca, u32 minRTT, u32 maxRTT) } if (ca->modeswitch && minRTT > msecs_to_jiffies(10) && maxRTT) { - ca->beta = (minRTT<<7)/maxRTT; + ca->beta = (minRTT << 7) / maxRTT; if (ca->beta < BETA_MIN) ca->beta = BETA_MIN; else if (ca->beta > BETA_MAX) @@ -169,23 +175,26 @@ static inline void htcp_alpha_update(struct htcp *ca) if (diff > HZ) { diff -= HZ; - factor = 1+ ( 10*diff + ((diff/2)*(diff/2)/HZ) )/HZ; + factor = 1 + (10 * diff + ((diff / 2) * (diff / 2) / HZ)) / HZ; } if (use_rtt_scaling && minRTT) { - u32 scale = (HZ<<3)/(10*minRTT); - scale = min(max(scale, 1U<<2), 10U<<3); /* clamping ratio to interval [0.5,10]<<3 */ - factor = (factor<<3)/scale; + u32 scale = (HZ << 3) / (10 * minRTT); + + /* clamping ratio to interval [0.5,10]<<3 */ + scale = min(max(scale, 1U << 2), 10U << 3); + factor = (factor << 3) / scale; if (!factor) factor = 1; } - ca->alpha = 2*factor*((1<<7)-ca->beta); + ca->alpha = 2 * factor * ((1 << 7) - ca->beta); if (!ca->alpha) ca->alpha = ALPHA_BASE; } -/* After we have the rtt data to calculate beta, we'd still prefer to wait one +/* + * After we have the rtt data to calculate beta, we'd still prefer to wait one * rtt before we adjust our beta to ensure we are working from a consistent * data. * @@ -202,15 +211,16 @@ static void htcp_param_update(struct sock *sk) htcp_beta_update(ca, minRTT, maxRTT); htcp_alpha_update(ca); - /* add slowly fading memory for maxRTT to accommodate routing changes etc */ + /* add slowly fading memory for maxRTT to accommodate routing changes */ if (minRTT > 0 && maxRTT > minRTT) - ca->maxRTT = minRTT + ((maxRTT-minRTT)*95)/100; + ca->maxRTT = minRTT + ((maxRTT - minRTT) * 95) / 100; } static u32 htcp_recalc_ssthresh(struct sock *sk) { const struct tcp_sock *tp = tcp_sk(sk); const struct htcp *ca = inet_csk_ca(sk); + htcp_param_update(sk); return max((tp->snd_cwnd * ca->beta) >> 7, 2U); } @@ -224,10 +234,9 @@ static void htcp_cong_avoid(struct sock *sk, u32 ack, u32 rtt, if (!tcp_is_cwnd_limited(sk, in_flight)) return; - if (tp->snd_cwnd <= tp->snd_ssthresh) + if (tp->snd_cwnd <= tp->snd_ssthresh) tcp_slow_start(tp); else { - measure_rtt(sk); /* In dangerous area, increase slowly. |