From: Stephen Hemminger <shemminger@vyatta•com>
To: "David S. Miller" <davem@davemloft•net>
Cc: netdev@vger•kernel.org
Subject: [PATCH 2/7] tcp_cubic: fix comparison of jiffies
Date: Mon, 14 Mar 2011 10:52:13 -0700 [thread overview]
Message-ID: <20110314175439.377973202@vyatta.com> (raw)
In-Reply-To: 20110314175211.788224699@vyatta.com
[-- Attachment #1: tcp-cubic-jiffies-wrap.patch --]
[-- Type: text/plain, Size: 1021 bytes --]
Jiffies wraps around therefore the correct way to compare is
to use cast to signed value.
Note: cubic is not using full jiffies value on 64 bit arch
because using full unsigned long makes struct bictcp grow too
large for the available ca_priv area.
Includes correction from Sangtae Ha to improve ack train detection.
Signed-off-by: Stephen Hemminger <shemminger@vyatta•com>
--- a/net/ipv4/tcp_cubic.c 2011-03-11 09:00:06.856664687 -0800
+++ b/net/ipv4/tcp_cubic.c 2011-03-11 09:02:11.685796371 -0800
@@ -342,9 +342,11 @@ static void hystart_update(struct sock *
u32 curr_jiffies = jiffies;
/* first detection parameter - ack-train detection */
- if (curr_jiffies - ca->last_jiffies <= msecs_to_jiffies(2)) {
+ if ((s32)(curr_jiffies - ca->last_jiffies) <=
+ msecs_to_jiffies(2)) {
ca->last_jiffies = curr_jiffies;
- if (curr_jiffies - ca->round_start >= ca->delay_min>>4)
+ if ((s32) (curr_jiffies - ca->round_start) >
+ ca->delay_min >> 4)
ca->found |= HYSTART_ACK_TRAIN;
}
next prev parent reply other threads:[~2011-03-14 18:02 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-03-14 17:52 [PATCH 0/7] TCP CUBIC Hystart fixes Stephen Hemminger
2011-03-14 17:52 ` [PATCH 1/7] tcp: fix RTT for quick packets in congestion control Stephen Hemminger
2011-03-14 17:52 ` Stephen Hemminger [this message]
2011-03-14 17:52 ` [PATCH 3/7] tcp_cubic: make ack train delta value a parameter Stephen Hemminger
2011-03-14 17:52 ` [PATCH 4/7] tcp_cubic: fix clock dependency Stephen Hemminger
2011-03-14 18:51 ` Eric Dumazet
2011-03-14 21:21 ` Stephen Hemminger
2011-03-14 21:37 ` Eric Dumazet
2011-03-14 17:52 ` [PATCH 5/7] tcp_cubic: enable high resolution ack time if needed Stephen Hemminger
2011-03-14 17:52 ` [PATCH 6/7] tcp_cubic: make the delay threshold of HyStart less sensitive Stephen Hemminger
2011-03-14 17:52 ` [PATCH 7/7] tcp_cubic: fix low utilization of CUBIC with HyStart Stephen Hemminger
2011-03-14 22:58 ` [PATCH 0/7] TCP CUBIC Hystart fixes David Miller
2011-03-22 11:34 ` Lucas Nussbaum
2011-03-22 11:35 ` Lucas Nussbaum
2011-03-22 12:05 ` David Miller
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