From 2b0a8c9eee81882fc0001ccf6d9af62cdc682f9e Mon Sep 17 00:00:00 2001 From: Kenneth Klette Jonassen Date: Wed, 10 Jun 2015 19:08:17 +0200 Subject: tcp: add CDG congestion control CAIA Delay-Gradient (CDG) is a TCP congestion control that modifies the TCP sender in order to [1]: o Use the delay gradient as a congestion signal. o Back off with an average probability that is independent of the RTT. o Coexist with flows that use loss-based congestion control, i.e., flows that are unresponsive to the delay signal. o Tolerate packet loss unrelated to congestion. (Disabled by default.) Its FreeBSD implementation was presented for the ICCRG in July 2012; slides are available at http://www.ietf.org/proceedings/84/iccrg.html Running the experiment scenarios in [1] suggests that our implementation achieves more goodput compared with FreeBSD 10.0 senders, although it also causes more queueing delay for a given backoff factor. The loss tolerance heuristic is disabled by default due to safety concerns for its use in the Internet [2, p. 45-46]. We use a variant of the Hybrid Slow start algorithm in tcp_cubic to reduce the probability of slow start overshoot. [1] D.A. Hayes and G. Armitage. "Revisiting TCP congestion control using delay gradients." In Networking 2011, pages 328-341. Springer, 2011. [2] K.K. Jonassen. "Implementing CAIA Delay-Gradient in Linux." MSc thesis. Department of Informatics, University of Oslo, 2015. Cc: Eric Dumazet Cc: Yuchung Cheng Cc: Stephen Hemminger Cc: Neal Cardwell Cc: David Hayes Cc: Andreas Petlund Cc: Dave Taht Cc: Nicolas Kuhn Signed-off-by: Kenneth Klette Jonassen Acked-by: Yuchung Cheng Signed-off-by: David S. Miller --- net/ipv4/Kconfig | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) (limited to 'net/ipv4/Kconfig') diff --git a/net/ipv4/Kconfig b/net/ipv4/Kconfig index d83071dccd74..6fb3c90ad726 100644 --- a/net/ipv4/Kconfig +++ b/net/ipv4/Kconfig @@ -615,6 +615,22 @@ config TCP_CONG_DCTCP For further details see: http://simula.stanford.edu/~alizade/Site/DCTCP_files/dctcp-final.pdf +config TCP_CONG_CDG + tristate "CAIA Delay-Gradient (CDG)" + default n + ---help--- + CAIA Delay-Gradient (CDG) is a TCP congestion control that modifies + the TCP sender in order to: + + o Use the delay gradient as a congestion signal. + o Back off with an average probability that is independent of the RTT. + o Coexist with flows that use loss-based congestion control. + o Tolerate packet loss unrelated to congestion. + + For further details see: + D.A. Hayes and G. Armitage. "Revisiting TCP congestion control using + delay gradients." In Networking 2011. Preprint: http://goo.gl/No3vdg + choice prompt "Default TCP congestion control" default DEFAULT_CUBIC @@ -646,6 +662,9 @@ choice config DEFAULT_DCTCP bool "DCTCP" if TCP_CONG_DCTCP=y + config DEFAULT_CDG + bool "CDG" if TCP_CONG_CDG=y + config DEFAULT_RENO bool "Reno" endchoice @@ -668,6 +687,7 @@ config DEFAULT_TCP_CONG default "veno" if DEFAULT_VENO default "reno" if DEFAULT_RENO default "dctcp" if DEFAULT_DCTCP + default "cdg" if DEFAULT_CDG default "cubic" config TCP_MD5SIG -- cgit