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authorStephen Hemminger <shemminger@linux-foundation.org>2007-03-06 20:21:20 -0800
committerDavid S. Miller <davem@sunset.davemloft.net>2007-04-25 22:23:48 -0700
commit43e683926f808cec9802466c27cee7499eda3d11 (patch)
tree869b0138282a4f4391906f805fbf272e51f296f7
parent[TCP] tcp_cubic: faster cube root (diff)
downloadlinux-dev-43e683926f808cec9802466c27cee7499eda3d11.tar.xz
linux-dev-43e683926f808cec9802466c27cee7499eda3d11.zip
[TCP] TCP Yeah: cleanup
Eliminate need for full 6/4/64 divide to compute queue. Variable maxqueue was really a constant. Fix indentation. Signed-off-by: Stephen Hemminger <shemminger@linux-foundation.org> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--net/ipv4/tcp_yeah.c42
1 files changed, 23 insertions, 19 deletions
diff --git a/net/ipv4/tcp_yeah.c b/net/ipv4/tcp_yeah.c
index 18355a2608e1..46dd1bee583a 100644
--- a/net/ipv4/tcp_yeah.c
+++ b/net/ipv4/tcp_yeah.c
@@ -74,7 +74,7 @@ static void tcp_yeah_pkts_acked(struct sock *sk, u32 pkts_acked)
}
static void tcp_yeah_cong_avoid(struct sock *sk, u32 ack,
- u32 seq_rtt, u32 in_flight, int flag)
+ u32 seq_rtt, u32 in_flight, int flag)
{
struct tcp_sock *tp = tcp_sk(sk);
struct yeah *yeah = inet_csk_ca(sk);
@@ -142,8 +142,8 @@ static void tcp_yeah_cong_avoid(struct sock *sk, u32 ack,
*/
if (yeah->cntRTT > 2) {
- u32 rtt;
- u32 queue, maxqueue;
+ u32 rtt, queue;
+ u64 bw;
/* We have enough RTT samples, so, using the Vegas
* algorithm, we determine if we should increase or
@@ -158,32 +158,36 @@ static void tcp_yeah_cong_avoid(struct sock *sk, u32 ack,
*/
rtt = yeah->minRTT;
- queue = (u32)div64_64((u64)tp->snd_cwnd * (rtt - yeah->baseRTT), rtt);
-
- maxqueue = TCP_YEAH_ALPHA;
-
- if (queue > maxqueue ||
- rtt - yeah->baseRTT > (yeah->baseRTT / TCP_YEAH_PHY)) {
-
- if (queue > maxqueue && tp->snd_cwnd > yeah->reno_count) {
- u32 reduction = min( queue / TCP_YEAH_GAMMA ,
- tp->snd_cwnd >> TCP_YEAH_EPSILON );
+ /* Compute excess number of packets above bandwidth
+ * Avoid doing full 64 bit divide.
+ */
+ bw = tp->snd_cwnd;
+ bw *= rtt - yeah->baseRTT;
+ do_div(bw, rtt);
+ queue = bw;
+
+ if (queue > TCP_YEAH_ALPHA ||
+ rtt - yeah->baseRTT > (yeah->baseRTT / TCP_YEAH_PHY)) {
+ if (queue > TCP_YEAH_ALPHA
+ && tp->snd_cwnd > yeah->reno_count) {
+ u32 reduction = min(queue / TCP_YEAH_GAMMA ,
+ tp->snd_cwnd >> TCP_YEAH_EPSILON);
tp->snd_cwnd -= reduction;
- tp->snd_cwnd = max( tp->snd_cwnd, yeah->reno_count);
+ tp->snd_cwnd = max(tp->snd_cwnd,
+ yeah->reno_count);
tp->snd_ssthresh = tp->snd_cwnd;
- }
+ }
if (yeah->reno_count <= 2)
- yeah->reno_count = max( tp->snd_cwnd>>1, 2U);
+ yeah->reno_count = max(tp->snd_cwnd>>1, 2U);
else
yeah->reno_count++;
- yeah->doing_reno_now =
- min_t( u32, yeah->doing_reno_now + 1 , 0xffffff);
-
+ yeah->doing_reno_now = min(yeah->doing_reno_now + 1,
+ 0xffffffU);
} else {
yeah->fast_count++;