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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 <shemminger@linux-foundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Stephen Hemminger
2007-04-23 22:28:23 -07:00
committed by David S. Miller
parent 164891aadf
commit 7752237e9f
4 changed files with 61 additions and 178 deletions
Download Patch File Download Diff File Expand all files Collapse all files

53
net/ipv4/tcp_yeah.c
View File

@ -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
@ -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;
@ -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;
@ -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.
*
@ -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
@ -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;
@ -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 ,
@ -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;
}
}