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[TCP] TCP YEAH: Use vegas dont copy it.
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Rather than using a copy of vegas code, the YEAH code should just have
it exported so there is common code.

Signed-off-by: Stephen Hemminger <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
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Stephen Hemminger authored and David S. Miller committed Apr 26, 2007
1 parent 164891a commit 7752237
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Showing 4 changed files with 61 additions and 178 deletions.
31 changes: 13 additions & 18 deletions net/ipv4/tcp_vegas.c
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Original file line number Diff line number Diff line change
Expand Up @@ -38,6 +38,8 @@

#include <net/tcp.h>

#include "tcp_vegas.h"

/* Default values of the Vegas variables, in fixed-point representation
* with V_PARAM_SHIFT bits to the right of the binary point.
*/
Expand All @@ -54,17 +56,6 @@ module_param(gamma, int, 0644);
MODULE_PARM_DESC(gamma, "limit on increase (scale by 2)");


/* Vegas variables */
struct vegas {
u32 beg_snd_nxt; /* right edge during last RTT */
u32 beg_snd_una; /* left edge during last RTT */
u32 beg_snd_cwnd; /* saves the size of the cwnd */
u8 doing_vegas_now;/* if true, do vegas for this RTT */
u16 cntRTT; /* # of RTTs measured within last RTT */
u32 minRTT; /* min of RTTs measured within last RTT (in usec) */
u32 baseRTT; /* the min of all Vegas RTT measurements seen (in usec) */
};

/* There are several situations when we must "re-start" Vegas:
*
* o when a connection is established
Expand All @@ -81,7 +72,7 @@ struct vegas {
* Instead we must wait until the completion of an RTT during
* which we actually receive ACKs.
*/
static inline void vegas_enable(struct sock *sk)
static void vegas_enable(struct sock *sk)
{
const struct tcp_sock *tp = tcp_sk(sk);
struct vegas *vegas = inet_csk_ca(sk);
Expand All @@ -104,13 +95,14 @@ static inline void vegas_disable(struct sock *sk)
vegas->doing_vegas_now = 0;
}

static void tcp_vegas_init(struct sock *sk)
void tcp_vegas_init(struct sock *sk)
{
struct vegas *vegas = inet_csk_ca(sk);

vegas->baseRTT = 0x7fffffff;
vegas_enable(sk);
}
EXPORT_SYMBOL_GPL(tcp_vegas_init);

/* Do RTT sampling needed for Vegas.
* Basically we:
Expand All @@ -120,7 +112,7 @@ static void tcp_vegas_init(struct sock *sk)
* o min-filter RTT samples from a much longer window (forever for now)
* to find the propagation delay (baseRTT)
*/
static void tcp_vegas_pkts_acked(struct sock *sk, u32 cnt, ktime_t last)
void tcp_vegas_pkts_acked(struct sock *sk, u32 cnt, ktime_t last)
{
struct vegas *vegas = inet_csk_ca(sk);
u32 vrtt;
Expand All @@ -138,15 +130,17 @@ static void tcp_vegas_pkts_acked(struct sock *sk, u32 cnt, ktime_t last)
vegas->minRTT = min(vegas->minRTT, vrtt);
vegas->cntRTT++;
}
EXPORT_SYMBOL_GPL(tcp_vegas_pkts_acked);

static void tcp_vegas_state(struct sock *sk, u8 ca_state)
void tcp_vegas_state(struct sock *sk, u8 ca_state)
{

if (ca_state == TCP_CA_Open)
vegas_enable(sk);
else
vegas_disable(sk);
}
EXPORT_SYMBOL_GPL(tcp_vegas_state);

/*
* If the connection is idle and we are restarting,
Expand All @@ -157,12 +151,13 @@ static void tcp_vegas_state(struct sock *sk, u8 ca_state)
* packets, _then_ we can make Vegas calculations
* again.
*/
static void tcp_vegas_cwnd_event(struct sock *sk, enum tcp_ca_event event)
void tcp_vegas_cwnd_event(struct sock *sk, enum tcp_ca_event event)
{
if (event == CA_EVENT_CWND_RESTART ||
event == CA_EVENT_TX_START)
tcp_vegas_init(sk);
}
EXPORT_SYMBOL_GPL(tcp_vegas_cwnd_event);

static void tcp_vegas_cong_avoid(struct sock *sk, u32 ack,
u32 seq_rtt, u32 in_flight, int flag)
Expand Down Expand Up @@ -339,8 +334,7 @@ static void tcp_vegas_cong_avoid(struct sock *sk, u32 ack,
}

/* Extract info for Tcp socket info provided via netlink. */
static void tcp_vegas_get_info(struct sock *sk, u32 ext,
struct sk_buff *skb)
void tcp_vegas_get_info(struct sock *sk, u32 ext, struct sk_buff *skb)
{
const struct vegas *ca = inet_csk_ca(sk);
if (ext & (1 << (INET_DIAG_VEGASINFO - 1))) {
Expand All @@ -354,6 +348,7 @@ static void tcp_vegas_get_info(struct sock *sk, u32 ext,
nla_put(skb, INET_DIAG_VEGASINFO, sizeof(info), &info);
}
}
EXPORT_SYMBOL_GPL(tcp_vegas_get_info);

static struct tcp_congestion_ops tcp_vegas = {
.flags = TCP_CONG_RTT_STAMP,
Expand Down
24 changes: 24 additions & 0 deletions net/ipv4/tcp_vegas.h
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Original file line number Diff line number Diff line change
@@ -0,0 +1,24 @@
/*
* TCP Vegas congestion control interface
*/
#ifndef __TCP_VEGAS_H
#define __TCP_VEGAS_H 1

/* Vegas variables */
struct vegas {
u32 beg_snd_nxt; /* right edge during last RTT */
u32 beg_snd_una; /* left edge during last RTT */
u32 beg_snd_cwnd; /* saves the size of the cwnd */
u8 doing_vegas_now;/* if true, do vegas for this RTT */
u16 cntRTT; /* # of RTTs measured within last RTT */
u32 minRTT; /* min of RTTs measured within last RTT (in usec) */
u32 baseRTT; /* the min of all Vegas RTT measurements seen (in usec) */
};

extern void tcp_vegas_init(struct sock *sk);
extern void tcp_vegas_state(struct sock *sk, u8 ca_state);
extern void tcp_vegas_pkts_acked(struct sock *sk, u32 cnt, ktime_t last);
extern void tcp_vegas_cwnd_event(struct sock *sk, enum tcp_ca_event event);
extern void tcp_vegas_get_info(struct sock *sk, u32 ext, struct sk_buff *skb);

#endif /* __TCP_VEGAS_H */
53 changes: 24 additions & 29 deletions net/ipv4/tcp_yeah.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -6,13 +6,14 @@
* http://wil.cs.caltech.edu/pfldnet2007/paper/YeAH_TCP.pdf
*
*/
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/inet_diag.h>

#include "tcp_yeah.h"
#include <net/tcp.h>

/* Default values of the Vegas variables, in fixed-point representation
* with V_PARAM_SHIFT bits to the right of the binary point.
*/
#define V_PARAM_SHIFT 1
#include "tcp_vegas.h"

#define TCP_YEAH_ALPHA 80 //lin number of packets queued at the bottleneck
#define TCP_YEAH_GAMMA 1 //lin fraction of queue to be removed per rtt
Expand All @@ -26,14 +27,7 @@

/* YeAH variables */
struct yeah {
/* Vegas */
u32 beg_snd_nxt; /* right edge during last RTT */
u32 beg_snd_una; /* left edge during last RTT */
u32 beg_snd_cwnd; /* saves the size of the cwnd */
u8 doing_vegas_now;/* if true, do vegas for this RTT */
u16 cntRTT; /* # of RTTs measured within last RTT */
u32 minRTT; /* min of RTTs measured within last RTT (in usec) */
u32 baseRTT; /* the min of all Vegas RTT measurements seen (in usec) */
struct vegas vegas; /* must be first */

/* YeAH */
u32 lastQ;
Expand Down Expand Up @@ -84,9 +78,10 @@ static void tcp_yeah_cong_avoid(struct sock *sk, u32 ack,
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 if (!yeah->doing_reno_now) {

else if (!yeah->doing_reno_now) {
/* Scalable */

tp->snd_cwnd_cnt+=yeah->pkts_acked;
Expand All @@ -110,19 +105,19 @@ static void tcp_yeah_cong_avoid(struct sock *sk, u32 ack,
}
}

/* The key players are v_beg_snd_una and v_beg_snd_nxt.
/* The key players are v_vegas.beg_snd_una and v_beg_snd_nxt.
*
* These are so named because they represent the approximate values
* of snd_una and snd_nxt at the beginning of the current RTT. More
* precisely, they represent the amount of data sent during the RTT.
* At the end of the RTT, when we receive an ACK for v_beg_snd_nxt,
* we will calculate that (v_beg_snd_nxt - v_beg_snd_una) outstanding
* we will calculate that (v_beg_snd_nxt - v_vegas.beg_snd_una) outstanding
* bytes of data have been ACKed during the course of the RTT, giving
* an "actual" rate of:
*
* (v_beg_snd_nxt - v_beg_snd_una) / (rtt duration)
* (v_beg_snd_nxt - v_vegas.beg_snd_una) / (rtt duration)
*
* Unfortunately, v_beg_snd_una is not exactly equal to snd_una,
* Unfortunately, v_vegas.beg_snd_una is not exactly equal to snd_una,
* because delayed ACKs can cover more than one segment, so they
* don't line up yeahly with the boundaries of RTTs.
*
Expand All @@ -132,7 +127,7 @@ static void tcp_yeah_cong_avoid(struct sock *sk, u32 ack,
* So we keep track of our cwnd separately, in v_beg_snd_cwnd.
*/

if (after(ack, yeah->beg_snd_nxt)) {
if (after(ack, yeah->vegas.beg_snd_nxt)) {

/* We do the Vegas calculations only if we got enough RTT
* samples that we can be reasonably sure that we got
Expand All @@ -143,7 +138,7 @@ static void tcp_yeah_cong_avoid(struct sock *sk, u32 ack,
* If we have 3 samples, we should be OK.
*/

if (yeah->cntRTT > 2) {
if (yeah->vegas.cntRTT > 2) {
u32 rtt, queue;
u64 bw;

Expand All @@ -158,18 +153,18 @@ static void tcp_yeah_cong_avoid(struct sock *sk, u32 ack,
* of delayed ACKs, at the cost of noticing congestion
* a bit later.
*/
rtt = yeah->minRTT;
rtt = yeah->vegas.minRTT;

/* Compute excess number of packets above bandwidth
* Avoid doing full 64 bit divide.
*/
bw = tp->snd_cwnd;
bw *= rtt - yeah->baseRTT;
bw *= rtt - yeah->vegas.baseRTT;
do_div(bw, rtt);
queue = bw;

if (queue > TCP_YEAH_ALPHA ||
rtt - yeah->baseRTT > (yeah->baseRTT / TCP_YEAH_PHY)) {
rtt - yeah->vegas.baseRTT > (yeah->vegas.baseRTT / TCP_YEAH_PHY)) {
if (queue > TCP_YEAH_ALPHA
&& tp->snd_cwnd > yeah->reno_count) {
u32 reduction = min(queue / TCP_YEAH_GAMMA ,
Expand Down Expand Up @@ -208,13 +203,13 @@ static void tcp_yeah_cong_avoid(struct sock *sk, u32 ack,
/* Save the extent of the current window so we can use this
* at the end of the next RTT.
*/
yeah->beg_snd_una = yeah->beg_snd_nxt;
yeah->beg_snd_nxt = tp->snd_nxt;
yeah->beg_snd_cwnd = tp->snd_cwnd;
yeah->vegas.beg_snd_una = yeah->vegas.beg_snd_nxt;
yeah->vegas.beg_snd_nxt = tp->snd_nxt;
yeah->vegas.beg_snd_cwnd = tp->snd_cwnd;

/* Wipe the slate clean for the next RTT. */
yeah->cntRTT = 0;
yeah->minRTT = 0x7fffffff;
yeah->vegas.cntRTT = 0;
yeah->vegas.minRTT = 0x7fffffff;
}
}

Expand Down
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