From: Stephen Hemminger <shemminger@vyatta•com>
To: "David S. Miller" <davem@davemloft•net>
Cc: netdev@vger•kernel.org
Subject: [PATCH 5/7] tcp_cubic: enable high resolution ack time if needed
Date: Mon, 14 Mar 2011 10:52:16 -0700 [thread overview]
Message-ID: <20110314175439.657008198@vyatta.com> (raw)
In-Reply-To: 20110314175211.788224699@vyatta.com
[-- Attachment #1: tcp-cubic-rtt-cong.patch --]
[-- Type: text/plain, Size: 726 bytes --]
This is a refined version of an earlier patch by Lucas Nussbaum.
Cubic needs RTT values in milliseconds. If HZ < 1000 then
the values will be too coarse.
Signed-off-by: Stephen Hemminger <shemminger@vyatta•com>
Reported-by: Lucas Nussbaum <lucas.nussbaum@loria•fr>
--- a/net/ipv4/tcp_cubic.c 2011-03-14 08:22:42.486690594 -0700
+++ b/net/ipv4/tcp_cubic.c 2011-03-14 08:27:24.435852847 -0700
@@ -459,6 +459,10 @@ static int __init cubictcp_register(void
/* divide by bic_scale and by constant Srtt (100ms) */
do_div(cube_factor, bic_scale * 10);
+ /* hystart needs ms clock resolution */
+ if (hystart && HZ < 1000)
+ cubictcp.flags |= TCP_CONG_RTT_STAMP;
+
return tcp_register_congestion_control(&cubictcp);
}
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 ` [PATCH 2/7] tcp_cubic: fix comparison of jiffies Stephen Hemminger
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 ` Stephen Hemminger [this message]
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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