From ddebc973c56b51b4e5d84d606f0430d81b895d67 Mon Sep 17 00:00:00 2001 From: Gerrit Renker Date: Sun, 4 Jan 2009 21:42:53 -0800 Subject: dccp: Lockless integration of CCID congestion-control plugins Based on Arnaldo's earlier patch, this patch integrates the standardised CCID congestion control plugins (CCID-2 and CCID-3) of DCCP with dccp.ko: * enables a faster connection path by eliminating the need to always go through the CCID registration lock; * updates the implementation to use only a single array whose size equals the number of configured CCIDs instead of the maximum (256); * since the CCIDs are now fixed array elements, synchronization is no longer needed, simplifying use and implementation. CCID-2 is suggested as minimum for a basic DCCP implementation (RFC 4340, 10); CCID-3 is a standards-track CCID supported by RFC 4342 and RFC 5348. Signed-off-by: Gerrit Renker Signed-off-by: David S. Miller --- net/dccp/ccids/Kconfig | 70 +++++++++++++++----------------------------------- 1 file changed, 21 insertions(+), 49 deletions(-) (limited to 'net/dccp/ccids/Kconfig') diff --git a/net/dccp/ccids/Kconfig b/net/dccp/ccids/Kconfig index 12275943eab8..b30f049cf1d3 100644 --- a/net/dccp/ccids/Kconfig +++ b/net/dccp/ccids/Kconfig @@ -1,80 +1,52 @@ menu "DCCP CCIDs Configuration (EXPERIMENTAL)" depends on EXPERIMENTAL -config IP_DCCP_CCID2 - tristate "CCID2 (TCP-Like) (EXPERIMENTAL)" - def_tristate IP_DCCP - select IP_DCCP_ACKVEC - ---help--- - CCID 2, TCP-like Congestion Control, denotes Additive Increase, - Multiplicative Decrease (AIMD) congestion control with behavior - modelled directly on TCP, including congestion window, slow start, - timeouts, and so forth [RFC 2581]. CCID 2 achieves maximum - bandwidth over the long term, consistent with the use of end-to-end - congestion control, but halves its congestion window in response to - each congestion event. This leads to the abrupt rate changes - typical of TCP. Applications should use CCID 2 if they prefer - maximum bandwidth utilization to steadiness of rate. This is often - the case for applications that are not playing their data directly - to the user. For example, a hypothetical application that - transferred files over DCCP, using application-level retransmissions - for lost packets, would prefer CCID 2 to CCID 3. On-line games may - also prefer CCID 2. See RFC 4341 for further details. - - CCID2 is the default CCID used by DCCP. - config IP_DCCP_CCID2_DEBUG - bool "CCID2 debugging messages" - depends on IP_DCCP_CCID2 - ---help--- - Enable CCID2-specific debugging messages. + bool "CCID-2 debugging messages" + ---help--- + Enable CCID-2 specific debugging messages. - When compiling CCID2 as a module, this debugging output can - additionally be toggled by setting the ccid2_debug module - parameter to 0 or 1. + The debugging output can additionally be toggled by setting the + ccid2_debug parameter to 0 or 1. - If in doubt, say N. + If in doubt, say N. config IP_DCCP_CCID3 - tristate "CCID3 (TCP-Friendly) (EXPERIMENTAL)" - def_tristate IP_DCCP + bool "CCID-3 (TCP-Friendly) (EXPERIMENTAL)" + def_bool y if (IP_DCCP = y || IP_DCCP = m) select IP_DCCP_TFRC_LIB ---help--- - CCID 3 denotes TCP-Friendly Rate Control (TFRC), an equation-based + CCID-3 denotes TCP-Friendly Rate Control (TFRC), an equation-based rate-controlled congestion control mechanism. TFRC is designed to be reasonably fair when competing for bandwidth with TCP-like flows, where a flow is "reasonably fair" if its sending rate is generally within a factor of two of the sending rate of a TCP flow under the same conditions. However, TFRC has a much lower variation of - throughput over time compared with TCP, which makes CCID 3 more - suitable than CCID 2 for applications such streaming media where a + throughput over time compared with TCP, which makes CCID-3 more + suitable than CCID-2 for applications such streaming media where a relatively smooth sending rate is of importance. - CCID 3 is further described in RFC 4342, + CCID-3 is further described in RFC 4342, http://www.ietf.org/rfc/rfc4342.txt The TFRC congestion control algorithms were initially described in - RFC 3448. + RFC 5448. This text was extracted from RFC 4340 (sec. 10.2), http://www.ietf.org/rfc/rfc4340.txt - - To compile this CCID as a module, choose M here: the module will be - called dccp_ccid3. - If in doubt, say M. + If in doubt, say N. config IP_DCCP_CCID3_DEBUG - bool "CCID3 debugging messages" - depends on IP_DCCP_CCID3 - ---help--- - Enable CCID3-specific debugging messages. + bool "CCID-3 debugging messages" + depends on IP_DCCP_CCID3 + ---help--- + Enable CCID-3 specific debugging messages. - When compiling CCID3 as a module, this debugging output can - additionally be toggled by setting the ccid3_debug module - parameter to 0 or 1. + The debugging output can additionally be toggled by setting the + ccid3_debug parameter to 0 or 1. - If in doubt, say N. + If in doubt, say N. config IP_DCCP_CCID3_RTO int "Use higher bound for nofeedback timer" -- cgit v1.2.3